1
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Fujii Y, Ioka H, Minamoto C, Kurisaki I, Tanaka S, Ohta K, Tominaga K. Vibrational frequency fluctuations of poly(N,N-diethylacrylamide) in the vicinity of coil-to-globule transition studied by two-dimensional infrared spectroscopy and molecular dynamics simulations. J Chem Phys 2024; 161:064903. [PMID: 39120037 DOI: 10.1063/5.0218180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Accepted: 07/24/2024] [Indexed: 08/10/2024] Open
Abstract
Poly(N,N-diethylacrylamide) (PdEA), one of the thermoresponsive polymers, in aqueous solutions has attracted much attention because of its characteristic properties, such as coil-to-globule (CG) transition. We performed two-dimensional infrared spectroscopy and molecular dynamics (MD) simulations to understand the hydration dynamics in the vicinity of the CG transition at the molecular level via vibrational frequency fluctuations of the carbonyl stretching modes in the side chains of PdEA. Furthermore, N,N-diethylpropionamide, a repeating monomer unit of PdEA, is also investigated for comparison. From decays of the frequency-frequency time correlation functions (FFTCFs) of the carbonyl stretching modes, we consider that inhomogeneity of the hydration environments originates from various backbone configurations of PdEA. The degree of the inhomogeneity depends on temperature. Hydration water molecules near the carbonyl groups are influenced by the confinements of the polymers. The restricted reorientation of the embedded water, the local torsions of the backbone, and the rearrangement of the whole structure contribute to the slow spectral diffusion. By performing MD simulations, we calculated the FFTCFs and dynamical quantities, such as fluctuations of the dihedral angles of the backbone and the orientation of the hydration water molecules. The simulated FFTCFs match well with the experimental results, indicating that the retarded water reorientations via the excluded volume effect play an important role in the vibrational frequency fluctuations of the carbonyl stretching mode. It is also found the embedded water molecules are influenced by the local torsions of the backbone structure within the time scales of the spectral diffusion.
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Affiliation(s)
- Yuki Fujii
- Department of Chemistry, Graduate School of Science, Kobe University, Rokkodai-cho 1-1, Nada, Kobe 657-8501, Japan
| | - Hikaru Ioka
- Department of Chemistry, Graduate School of Science, Kobe University, Rokkodai-cho 1-1, Nada, Kobe 657-8501, Japan
| | - Chihiro Minamoto
- Department of Applied Chemistry and Biotechnology, Niihama National College of Technology, Yakumo-cho 7-1, Niihama, Ehime 792-8580, Japan
| | - Ikuo Kurisaki
- Waseda Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Shigenori Tanaka
- Department of Computational Science, Graduate School of System Informatics, Kobe University, Rokkodai-cho 1-1, Nada, Kobe 657-8501, Japan
| | - Kaoru Ohta
- Molecular Photoscience Research Center, Kobe University, Rokkodai-cho 1-1, Nada, Kobe 657-8501, Japan
| | - Keisuke Tominaga
- Department of Chemistry, Graduate School of Science, Kobe University, Rokkodai-cho 1-1, Nada, Kobe 657-8501, Japan
- Molecular Photoscience Research Center, Kobe University, Rokkodai-cho 1-1, Nada, Kobe 657-8501, Japan
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2
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Amini N, Fan B, Hsia T, Moon EM, Hapgood K, Thang SH. RAFT Polymer-Based Surfactants for Minerals Recovery. ACS OMEGA 2023; 8:40532-40546. [PMID: 37929102 PMCID: PMC10620920 DOI: 10.1021/acsomega.3c05270] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 09/29/2023] [Indexed: 11/07/2023]
Abstract
Reagent consumption is an ongoing sustainability challenge for the mineral processing industry. There is a need to recover, regenerate, and reuse as many of the chemical inputs as possible. This study investigated the design and synthesis via reversible addition-fragmentation chain transfer (RAFT) polymerization of a novel polymer for use as a surfactant in a water-in-oil (w/o) emulsion system for ultrafine minerals recovery. The polymers were designed to hold a thermoresponsive moiety to allow for future recovery. The performance of the novel emulsion was tested for agglomeration of ultrafine talc mineral particles. A traditional emulsion containing sorbitan monooleate as the surfactant was used as a research benchmark to compare against the novel emulsion's stability and performance in minerals recovery. The novel RAFT polymer-based emulsions formed large and stable water droplets surrounded by a halo of smaller water droplets. Over time, the smaller droplets coalesced and a more uniform size distribution of droplets was formed, keeping the emulsion stable. Rheological testing of freshly made and aged emulsions showed both traditional and novel emulsions to have a high viscosity at a low shear rate. RAFT polymer B with a hydrophilic-lipophilic block ratio of 5:10 performed adequately as a surfactant replacement to stabilize w/o emulsions. The mineral recovery using the novel emulsion was on par with the traditional emulsions. The novel RAFT emulsion containing 2.5 wt % polymer B achieved 90% minerals recovery, a similar yield to the traditional emulsions. This study demonstrates that surfactants containing stimuli-responsive moieties can be synthesized via RAFT polymerization and successfully used in mineral processing applications to recover ultrafine particles. Work is ongoing to exploit the stimuli responsiveness to recover the polymer surfactant for reuse.
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Affiliation(s)
- Negin Amini
- School
of Engineering, Deakin University, Waurn Ponds, VIC 3216, Australia
- ARC
Centre of Excellence for Enabling Eco-efficient Beneficiation of Minerals
| | - Bo Fan
- School
of Chemistry, Monash University, Clayton Campus, VIC 3800, Australia
- ARC
Centre of Excellence for Enabling Eco-efficient Beneficiation of Minerals
| | - Tina Hsia
- School
of Chemistry, Monash University, Clayton Campus, VIC 3800, Australia
- ARC
Centre of Excellence for Enabling Eco-efficient Beneficiation of Minerals
| | - Ellen M. Moon
- School
of Engineering, Deakin University, Waurn Ponds, VIC 3216, Australia
- ARC
Centre of Excellence for Enabling Eco-efficient Beneficiation of Minerals
| | - Karen Hapgood
- Swinburne
University, Hawthorn, VIC 3122, Australia
- ARC
Centre of Excellence for Enabling Eco-efficient Beneficiation of Minerals
| | - San H. Thang
- School
of Chemistry, Monash University, Clayton Campus, VIC 3800, Australia
- ARC
Centre of Excellence for Enabling Eco-efficient Beneficiation of Minerals
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3
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Shi Y, He X. Effect of Tacticity Sequence of the Poly( N-isopropylacrylamide) Oligomer on Phase Transition Behavior in Aqueous Solution. J Phys Chem B 2023; 127:8660-8668. [PMID: 37756642 DOI: 10.1021/acs.jpcb.3c03765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
The tacticity of poly(N-isopropylacrylamide) (PNIPAM) has a strong impact on the lower critical solution temperature (LCST) in aqueous solution. The sequence of meso diads (m) and racemo diads (r) further contributes to such an effect. In this work, the phase transition behaviors of poly(N-isopropylacrylamide) pentamers with four kinds of sequences, i.e., rrmm, rmmr, mrrm, and rmrm, in water were studied applying replica exchange molecular dynamics with a modified OPLS/AA force field. The difference in local component concentration in the system was used as an order parameter to quantitatively describe the phase separation extent. It was found that the phase separation degree of rrmm and rmmr is higher than that of mrrm and rmrm at the same temperature. The LCSTs of rrmm and rmmr are lower than those of mrrm and rmrm. The radial distribution function and hydrogen bond analysis revealed that the average values of hydrogen bonds between pentamers for rrmm and rmmr are greater than those of mrrm and rmrm, whereas the average values of hydrogen bonds between pentamers and water for rrmm and rmmr are less than those of mrrm and rmrm. It was demonstrated that the isotactic triad (mm) plays an important role in the thermosensitive behaviors of the PNIPAM pentamer. The increase of isotactic triad (mm) content in the PNIPAM chain promotes the formation of intermolecular hydrogen bonds between amide and amide and leads to a higher aggregation of the pentamer with the sequence of rrmm or rmmr. Finally, the effect of the isotactic triad was qualitatively explained with the mean-field theory.
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Affiliation(s)
- Yi Shi
- Department of Chemistry, School of Science, Tianjin University, 300072 Tianjin, China
| | - Xuehao He
- Department of Chemistry, School of Science, Tianjin University, 300072 Tianjin, China
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4
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Zhang Y, Tang H, Zhou J, Zhang L, Wang R. Designing Multimodal ON-OFF Nanoswitches of DNA-Functionalized Nanoparticles by Stimuli-Responsive Polymers. J Phys Chem B 2023; 127:8049-8056. [PMID: 37699428 DOI: 10.1021/acs.jpcb.3c04409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/14/2023]
Abstract
It is a challenging task to realize highly reversible ON-OFF nanoswitches over a wide range of temperatures, which emerge as a versatile toolbox for use in nanobiotechnology. Herein, nanoparticles (NPs) bifunctionalized by DNA strands and stimuli-responsive polymers are proposed to construct multimodal ON-OFF nanoswitches by the coarse-grained model. The successful achievement of multimodal ON-OFF nanoswitches for bifunctionalized NPs at lower temperatures is attributed to the synergistic effects of the contraction and expansion configurations of stimuli-responsive polymers, combined with the hybridization-dehybridization event of DNA strands. Importantly, our simulations isolate the conditions of programmable self-assembly of bifunctionalized NPs to realize the multimodal ON-OFF nanoswitches by the changes of temperature and chain rigidity. In addition, it is found that the bifunctionalized NPs in the ON state display anisotropic and patchy features due to an introduction of stimuli-responsive polymers. Our simulation results provide fundamental insights on qualitative predictions of ON/OFF states of DNA-based NPs, which can aid in realizing a set of ON-OFF nanoswitches by the rational design of functionalization molecules.
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Affiliation(s)
- Yixin Zhang
- Department of Polymer Science and Engineering, State Key Laboratory of Coordination Chemistry, Key Laboratory of High Performance Polymer Materials and Technology of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Hao Tang
- Department of Polymer Science and Engineering, State Key Laboratory of Coordination Chemistry, Key Laboratory of High Performance Polymer Materials and Technology of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Junwei Zhou
- Department of Polymer Science and Engineering, State Key Laboratory of Coordination Chemistry, Key Laboratory of High Performance Polymer Materials and Technology of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Liangshun Zhang
- Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Rong Wang
- Department of Polymer Science and Engineering, State Key Laboratory of Coordination Chemistry, Key Laboratory of High Performance Polymer Materials and Technology of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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5
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Zbonikowski R, Iwan M, Paczesny J. Stimuli-Responsive Langmuir Films Composed of Nanoparticles Decorated with Poly( N-isopropyl acrylamide) (PNIPAM) at the Air/Water Interface. ACS OMEGA 2023; 8:23706-23719. [PMID: 37426285 PMCID: PMC10323952 DOI: 10.1021/acsomega.3c01862] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 05/16/2023] [Indexed: 07/11/2023]
Abstract
The nanotechnology shift from static toward stimuli-responsive systems is gaining momentum. We study adaptive and responsive Langmuir films at the air/water interface to facilitate the creation of two-dimensional (2D) complex systems. We verify the possibility of controlling the assembly of relatively large entities, i.e., nanoparticles with diameter around 90 nm, by inducing conformational changes within an about 5 nm poly(N-isopropyl acrylamide) (PNIPAM) capping layer. The system performs reversible switching between uniform and nonuniform states. The densely packed and uniform state is observed at a higher temperature, i.e., opposite to most phase transitions, where more ordered phases appear at lower temperatures. The induced nanoparticles' conformational changes result in different properties of the interfacial monolayer, including various types of aggregation. The analysis of surface pressure at different temperatures and upon temperature changes, surface potential measurements, surface rheology experiments, Brewster angle microscopy (BAM), and scanning electron microscopy (SEM) observations are accompanied by calculations to discuss the principles of the nanoparticles' self-assembly. Those findings provide guidelines for designing other adaptive 2D systems, such as programable membranes or optical interfacial devices.
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6
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Potential Applications of Thermoresponsive Poly( N-Isoproplacrylamide)-Grafted Nylon Membranes: Effect of Grafting Yield and Architecture on Gating Performance. Polymers (Basel) 2023; 15:polym15030497. [PMID: 36771798 PMCID: PMC9920928 DOI: 10.3390/polym15030497] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/11/2023] [Accepted: 01/12/2023] [Indexed: 01/20/2023] Open
Abstract
This study illustrated the potential applications of thermoresponsive poly(N-isopropylacrylamide) (PNIPAm) grafted nylon membranes with different grafting yields and grafting architecture. The thermoresponsive gating performance at temperatures below and above the lower critical solution temperature (LCST) of PNIPAm (32 °C) were demonstrated. The linear PNIPAm-grafted nylon membrane exhibited a sharp response over the temperature range 20-40 °C. The grafting yield of 25.5% and 21.9%, for linear and crosslinked PNIPAm respectively, exhibited highest thermoresponsive gating function for water flux and had a stable and repeatable "open-closed" switching function over 5 cycle operations. An excellent oil/water separation was obtained at T < 32 °C, at which the hydrophilic behavior was observed. The linear PNIPAm-grafted nylon membrane with 35% grafting yield had the highest separation efficiency of 99.7%, while PNIPAm structures were found to be independent of the separation efficiency. In addition, the membranes with thermoresponsive gas permeability were successfully achieved. The O2 and CO2 transmission rates through the PNIPAm-grafted nylon membranes decreased when the grafting yield increased, showing the better gas barrier property. The permeability ratio of CO2 to O2 transmission rates of both PNIPAm architectures at 25 °C and 35 °C were around 0.85 for low grafting yields, and approximately 1 for high grafting yields. Ultimately, this study demonstrated the possibility of using these thermoresponsive smart membranes in various applications.
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7
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Nagumo R, Nishikawa K, Sato A, Ogita A, Iwata S. Molecular dynamics simulations of the folding structure of a thermoresponsive 2-dimethylaminoethyl methacrylate oligomer in the globule state. Polym J 2022. [DOI: 10.1038/s41428-022-00705-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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8
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Pasban S, Raissi H. PNIPAM/Hexakis as a thermosensitive drug delivery system for biomedical and pharmaceutical applications. Sci Rep 2022; 12:14363. [PMID: 35999242 PMCID: PMC9399122 DOI: 10.1038/s41598-022-18459-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 08/11/2022] [Indexed: 11/29/2022] Open
Abstract
Many technologies ranging from drug delivery approaches to tissue engineering purposes are beginning to benefit from the unique ability of "smart polymers." As a special case, thermo-sensitive hydrogels have great potential, e.g. in actuators, microfluidics, sensors, or drug delivery systems. Here, the loading of Doxorubicin (DOX) with novel thermo-sensitive polymer N-isopropyl acrylamide (PNIPAM) and its copolymers are investigated in order to increase the Doxorubicin's drug efficacy on the targeted tumor site. Therefore, a rational design accurate based on the use of classical molecular dynamics (MD) and well-tempered metadynamics simulations allows for predicting and understanding the behavior of thermo-responsive polymers in the loading of DOX on Hexakis nano-channel at 298 and 320 K. Furthermore, this work investigates the efficacy of this drug carrier for the release of DOX in response to stimuli like variations in temperature and changes in the physiological pH. The study concludes that the Hexakis-polymer composite is capable of adsorbing the DOX at neutral pH and by increasing the temperature of the simulated systems from 298 to 320 K, the strength of intermolecular attraction decreases. In addition, the obtained results of MD simulation revealed that the dominant interaction between DOX and Hexakis in the DOX/polymer/Hexakis systems is the Lennard-Jones (LJ) term due to the formation of strong π-π interaction between the adsorbate and substrate surface. Obtained results show that a higher aggregation of DMA chains around the Hexakis and the formation of stronger bonds with DOX. The results of the well-tempered metadynamics simulations revealed that the order of insertion of drug and polymer into the system is a determining factor on the fate of the adsorption/desorption process. Overall, our results explain the temperature-dependent behavior of the PNIPAM polymers and the suitability of the polymer-Hexakis carrier for Doxorubicin delivery.
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Affiliation(s)
- Samaneh Pasban
- Department of Chemistry, University of Birjand, Birjand, Iran
| | - Heidar Raissi
- Department of Chemistry, University of Birjand, Birjand, Iran.
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9
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Tavagnacco L, Zaccarelli E, Chiessi E. Modeling Solution Behavior of Poly( N-isopropylacrylamide): A Comparison between Water Models. J Phys Chem B 2022; 126:3778-3788. [PMID: 35491838 PMCID: PMC9150113 DOI: 10.1021/acs.jpcb.2c00637] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
![]()
Water is known to
play a fundamental role in determining the structure
and functionality of macromolecules. The same crucial contribution
is also found in the in silico description of polymer aqueous solutions.
In this work, we exploit the widely investigated synthetic polymer
poly(N-isopropylacrylamide) (PNIPAM) to understand
the effect of the adopted water model on its solution behavior and
to refine the computational setup. By means of atomistic molecular
dynamics simulations, we perform a comparative study of PNIPAM aqueous
solution using two advanced water models: TIP4P/2005 and TIP4P/Ice.
The conformation and hydration features of an atactic 30-mer at infinite
dilution are probed at a range of temperature and pressure suitable
to detect the coil-to-globule transition and to map the P–T
phase diagram. Although both water models can reproduce the temperature-induced
coil-to-globule transition at atmospheric pressure and the polymer
hydration enhancement that occurs with increasing pressure, the PNIPAM–TIP4P/Ice
solution shows better agreement with experimental findings. This result
can be attributed to a stronger interaction of TIP4P/Ice water with
both hydrophilic and hydrophobic groups of PNIPAM, as well as to a
less favorable contribution of the solvent entropy to the coil-to-globule
transition.
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Affiliation(s)
- Letizia Tavagnacco
- CNR-ISC and Department of Physics, Sapienza University of Rome, Piazzale A, Moro 2, Rome 00185, Italy
| | - Emanuela Zaccarelli
- CNR-ISC and Department of Physics, Sapienza University of Rome, Piazzale A, Moro 2, Rome 00185, Italy
| | - Ester Chiessi
- Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica I, Rome 00133, Italy
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10
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Velychkivska N, Sedláček O, Shatan AB, Spasovová M, Filippov SK, Chahal MK, Janisova L, Brus J, Hanyková L, Hill JP, Winnik FM, Labuta J. Phase Separation and pH-Dependent Behavior of Four-Arm Star-Shaped Porphyrin-PNIPAM 4 Conjugates. Macromolecules 2022. [DOI: 10.1021/acs.macromol.1c02188] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Nadiia Velychkivska
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
- Institute of Macromolecular Chemistry, AS CR, Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic
| | - Ondřej Sedláček
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 40 Prague 2, Czech Republic
| | - Anastasiia B. Shatan
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
- Institute of Macromolecular Chemistry, AS CR, Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 40 Prague 2, Czech Republic
| | - Monika Spasovová
- Department of Macromolecular Physics, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, 180 00 Prague 8, Czech Republic
| | - Sergey K. Filippov
- Pharmaceutical Sciences Laboratory and Turku Bioscience Center of ÅboAkademi University, Tykistökatu 6A, 20520 Turku, Finland
| | - Mandeep K. Chahal
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Larisa Janisova
- Institute of Macromolecular Chemistry, AS CR, Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic
| | - Jiří Brus
- Institute of Macromolecular Chemistry, AS CR, Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic
| | - Lenka Hanyková
- Department of Macromolecular Physics, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, 180 00 Prague 8, Czech Republic
| | - Jonathan P. Hill
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Francoise M. Winnik
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
- Department of Chemistry, University of Helsinki, P.O. Box 55, Helsinki Fl-00014, Finland
| | - Jan Labuta
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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11
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Zhou D, Wan LS, Xu ZK, Mochizuki K. Less-Ordered Hydration Shell around Poly( N, N-diethylacrylamide) Is Insensitive to the Clouding Transition. J Phys Chem B 2021; 125:12104-12109. [PMID: 34668702 DOI: 10.1021/acs.jpcb.1c07966] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Raman multivariate curve resolution (Raman-MCR) is applied to examine how the hydration shell around poly(N,N-diethylacrylamide) (PDEAM) changes upon heating, in comparison with poly(N-isopropylacrylamide) (PNIPAM), both of which undergo a clouding transition near room temperature. We report that PDEAM possesses a less-ordered and smaller hydration shell than PNIPAM. Furthermore, the PDEAM hydration-shell structure is insensitive to the occurrence of clouding, indicating the coil-globule transition and aggregation of multiple chains can be achieved without the hydration-shell structural transformation.
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Affiliation(s)
- Di Zhou
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, MOE Engineering Research Center of Membrane and Water Treatment Technology, and Key Laboratory of Adsorption and Separation Materials & Technologies of Zhejiang Province, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Ling-Shu Wan
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, MOE Engineering Research Center of Membrane and Water Treatment Technology, and Key Laboratory of Adsorption and Separation Materials & Technologies of Zhejiang Province, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Zhi-Kang Xu
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, MOE Engineering Research Center of Membrane and Water Treatment Technology, and Key Laboratory of Adsorption and Separation Materials & Technologies of Zhejiang Province, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Kenji Mochizuki
- Department of Chemistry, Zhejiang University, Hangzhou 310028, China
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12
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Quoika PK, Fernández-Quintero ML, Podewitz M, Hofer F, Liedl KR. Implementation of the Freely Jointed Chain Model to Assess Kinetics and Thermodynamics of Thermosensitive Coil-Globule Transition by Markov States. J Phys Chem B 2021; 125:4898-4909. [PMID: 33942614 PMCID: PMC8154620 DOI: 10.1021/acs.jpcb.1c01946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
![]()
We revived and implemented
a method developed by Kuhn in 1934,
originally only published in German, that is, the so-called “freely
jointed chain” model. This approach turned out to be surprisingly
useful for analyzing state-of-the-art computer simulations of the
thermosensitive coil–globule transition of N-Isopropylacrylamide 20-mer. Our atomistic computer simulations are
orders of magnitude longer than those of previous studies and lead
to a reliable description of thermodynamics and kinetics at many different
temperatures. The freely jointed chain model provides a coordinate
system, which allows us to construct a Markov state model of the conformational
transitions. Furthermore, this guarantees a reliable reconstruction
of the kinetics in back-and-forth directions. In addition, we obtain
a description of the high diversity and variability of both conformational
states. Thus, we gain a detailed understanding of the coil–globule
transition. Surprisingly, conformational entropy turns out to play
only a minor role in the thermodynamic balance of the process. Moreover,
we show that the radius of gyration is an unexpectedly unsuitable
coordinate to comprehend the transition kinetics because it does not
capture the high conformational diversity within the different states.
Consequently, the approach presented here allows for an exhaustive
description and resolution of the conformational ensembles of arbitrary
linear polymer chains.
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Affiliation(s)
- Patrick K Quoika
- Institute of General, Inorganic and Theoretical Chemistry, and Centre of Molecular Biosciences University of Innsbruck, A-6020 Innsbruck, Austria
| | - Monica L Fernández-Quintero
- Institute of General, Inorganic and Theoretical Chemistry, and Centre of Molecular Biosciences University of Innsbruck, A-6020 Innsbruck, Austria
| | - Maren Podewitz
- Institute of General, Inorganic and Theoretical Chemistry, and Centre of Molecular Biosciences University of Innsbruck, A-6020 Innsbruck, Austria
| | - Florian Hofer
- Institute of General, Inorganic and Theoretical Chemistry, and Centre of Molecular Biosciences University of Innsbruck, A-6020 Innsbruck, Austria
| | - Klaus R Liedl
- Institute of General, Inorganic and Theoretical Chemistry, and Centre of Molecular Biosciences University of Innsbruck, A-6020 Innsbruck, Austria
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13
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Yang XD, Chen W, Ren Y, Chu LY. Exploring the structural transition mechanisms of a pair of poly( N-isopropylacrylamide) chains in aqueous solution through coarse-grained molecular simulations coupled with metadynamics. MOLECULAR SIMULATION 2021. [DOI: 10.1080/08927022.2021.1881086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Xue-Dan Yang
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan, People's Republic of China
- State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, Sichuan, People's Republic of China
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Wei Chen
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, People's Republic of China
- Dalian National Laboratory for Clean Energy, Chinese Academy of Sciences, Dalian, Liaoning, People's Republic of China
| | - Ying Ren
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, People's Republic of China
- Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Liang-Yin Chu
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan, People's Republic of China
- State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, Sichuan, People's Republic of China
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14
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Lee C, Kang S, Seo J, Lee J. Temperature-Responsive On-Off Control over Water Evaporation Achieved via Sweat-Gland-Mimetic Composites. ACS APPLIED MATERIALS & INTERFACES 2021; 13:4442-4449. [PMID: 33428372 DOI: 10.1021/acsami.0c16292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Responsive cooling materials that mimic sweat glands have gained popularity because they are efficient and do not require artificial energy sources. Temperature-responsive hydrogels sweat above their volume transition temperature through the release of water and exhibit excellent cooling ability. However, thus far, practical applications have not been possible because the water in these materials cannot be preserved in cool environments. To address this issue, this paper presents a simple composite of poly(N-isopropylacrylamide) and polydimethylsiloxane that offers excellent on-off control over water evaporation and can be used repeatedly; the proposed composite features an evaporation rate of 2.97 g/h above the lower critical solution temperature (LCST) and 0.08 g/h below the LCST. This 35.7-fold change in the water evaporation rate is comparable to that in mammalian sweat glands. The responsive on-off control relies on the structures of the composite and the dry layers formed on the surface of the composite in cool environments. The proposed material effectively regulates water evaporation and offers a novel, low-cost cooling strategy suitable for numerous applications.
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Affiliation(s)
- CheongCheon Lee
- Department of Chemical Engineering and Material Science, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Seulki Kang
- Department of Chemical Engineering and Material Science, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Jiwon Seo
- Department of Chemical Engineering and Material Science, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Jonghwi Lee
- Department of Chemical Engineering and Material Science, Chung-Ang University, Seoul 06974, Republic of Korea
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15
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Gosecki M, Ziemczonek P, Maczugowska P, Czaderna-Lekka A, Kozanecki M, Gosecka M. The influence of 2-acrylamidephenylboronic acid on the phase behaviour of its copolymers with N-isopropylacrylamide in aqueous solution. Polym Chem 2021. [DOI: 10.1039/d1py00397f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In this study, we report the synthesis and phase behaviour of statistical p(N-isopropylacrylamide-co-2-acrylamidephenylboronic acid), P(NIPAM-co-2-AAPBA) copolymers.
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Affiliation(s)
- Mateusz Gosecki
- Polymer Division
- Centre of Molecular and Macromolecular Studies
- Polish Academy of Science
- Poland
- 90-363 Lodz
| | - Piotr Ziemczonek
- Polymer Division
- Centre of Molecular and Macromolecular Studies
- Polish Academy of Science
- Poland
- 90-363 Lodz
| | - Paulina Maczugowska
- Department of Molecular Physics
- Faculty of Chemistry
- Lodz University of Technology
- 90-924 Lodz
- Poland
| | - Anna Czaderna-Lekka
- Department of Molecular Physics
- Faculty of Chemistry
- Lodz University of Technology
- 90-924 Lodz
- Poland
| | - Marcin Kozanecki
- Department of Molecular Physics
- Faculty of Chemistry
- Lodz University of Technology
- 90-924 Lodz
- Poland
| | - Monika Gosecka
- Polymer Division
- Centre of Molecular and Macromolecular Studies
- Polish Academy of Science
- Poland
- 90-363 Lodz
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16
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Gobeze HB, Ma J, Leonik FM, Kuroda DG. Bottom-Up Approach to Assess the Molecular Structure of Aqueous Poly( N-Isopropylacrylamide) at Room Temperature via Infrared Spectroscopy. J Phys Chem B 2020; 124:11699-11710. [PMID: 33306373 PMCID: PMC7872429 DOI: 10.1021/acs.jpcb.0c08424] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The structure of poly(N-isopropylacrylamide) (PNIPAM) in solution is still an unresolved topic. Here, the PNIPAM structure in water was investigated using a bottom-up approach, involving the monomer, dimer, and trimer, and a combination of infrared (IR) spectroscopies as well as molecular dynamics simulations. The experiments show that the monomer and oligomers exhibit a broad and asymmetric amide I band with two underlying transitions, while PNIPAM presents the same major transitions and a minor one. Analysis of the 2D IR spectra and theoretical modeling of the amide I band indicates that the two transitions of the monomer do not have the same molecular origin as the oligomers and the polymer. In the monomer, the two bands originate from the ultrafast rotation of its ethyl group, which leads to different solvation structures for the various rotational conformers. In the case of the oligomers, the asymmetry and splitting of the amide I band is caused by the vibrational coupling among adjacent amide side chains. Moreover, it is deduced from the simulations that the oligomers have three distinct backbone conformations for neighboring amides. In particular, two of the backbone conformations have a closed and compact structure, while in the third, the backbone is open and elongated. The bottom-up approach allowed us to infer that such backbone conformations exist in PNIPAM as well. Consequently, the two major amide I transitions of the polymer are also assigned to split amide I transitions resulting from the vibrationally coupled nearest-neighboring amides. In contrast, the additional minor transition observed in PNIPAM is assigned to unsolvated amide units of the polymer. The proposed molecular model successfully describes that PNIPAM amide I band changes with temperature in terms of its molecular structure. This new model strongly suggests that PNIPAM does not have a completely random backbone structure, but has distinct backbone conformers between neighboring amides.
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Affiliation(s)
- Habtom B Gobeze
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Jianbo Ma
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Fedra M Leonik
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Daniel G Kuroda
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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17
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Raccio S, Pollard J, Djuhadi A, Balog S, Pellizzoni MM, Rodriguez KJ, Rifaie-Graham O, Bruns N. Rapid quantification of the malaria biomarker hemozoin by improved biocatalytically initiated precipitation atom transfer radical polymerizations. Analyst 2020; 145:7741-7751. [PMID: 33000767 DOI: 10.1039/d0an00976h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The fight against tropical diseases such as malaria requires the development of innovative biosensing techniques. Diagnostics must be rapid and robust to ensure prompt case management and to avoid further transmission. The malaria biomarker hemozoin can catalyze atom transfer radical polymerizations (ATRP), which we exploit in a polymerization-amplified biosensing assay for hemozoin based on the precipitation polymerization of N-isopropyl acrylamide (NIPAAm). The reaction conditions are systematically investigated using synthetic hemozoin to gain fundamental understanding of the involved reactions and to greatly reduce the amplification time, while maintaining the sensitivity of the assay. The use of excess ascorbate allows oxygen to be consumed in situ but leads to the formation of reactive oxygen species and to the decomposition of the initiator 2-hydroxyethyl 2-bromoisobutyrate (HEBIB). Addition of sodium dodecyl sulfate (SDS) and pyruvate results in better differentiation between the blank and hemozoin-containing samples. Optimized reaction conditions (including reagents, pH, and temperature) reduce the amplification time from 37 ± 5 min to 3 ± 0.5 min while maintaining a low limit of detection of 1.06 ng mL-1. The short amplification time brings the precipitation polymerization assay a step closer to a point-of-care diagnostic device for malaria. Future efforts will be dedicated to the isolation of hemozoin from clinical samples.
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Affiliation(s)
- Samuel Raccio
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
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18
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Comparison based on statistical thermodynamics between globule-to-coil transition of poly(N-isopropylacrylamide) and cold denaturation of a protein. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.114129] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Entropy Rules: Molecular Dynamics Simulations of Model Oligomers for Thermoresponsive Polymers. ENTROPY 2020; 22:e22101187. [PMID: 33286955 PMCID: PMC7597358 DOI: 10.3390/e22101187] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/02/2020] [Accepted: 10/09/2020] [Indexed: 11/17/2022]
Abstract
We attempted to attain atomic-scale insights into the mechanism of the heat-induced phase transition of two thermoresponsive polymers containing amide groups, poly(N-isopropylacrylamide) (PNIPAM) and poly(2-isopropyl-2-oxazoline) (PIPOZ), and we succeeded in reproducing the existence of lower critical solution temperature (LCST). The simulation data are in accord with experimental findings. We found out that the entropy has an important contribution to the thermodynamics of the phase separation transition. Moreover, after decomposing further the entropy change to contributions from the solutes and from the solvent, it appeared out that the entropy of the solvent has the decisive share for the lowering of the free energy of the system when increasing the temperature above the LCST. Our conclusion is that the thermoresponsive behavior is driven by the entropy of the solvent. The water molecules structured around the functional groups of the polymer that are exposed to contact with the solvent in the extended conformation lower the enthalpy of the system, but at certain temperature the extended conformation of the polymer collapses as a result of dominating entropy gain from “released” water molecules. We stress also on the importance of using more than one reference molecule in the simulation box at the setup of the simulation.
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20
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Quoika PK, Podewitz M, Wang Y, Kamenik AS, Loeffler JR, Liedl KR. Thermosensitive Hydration of Four Acrylamide-Based Polymers in Coil and Globule Conformations. J Phys Chem B 2020; 124:9745-9756. [PMID: 33054215 PMCID: PMC7604866 DOI: 10.1021/acs.jpcb.0c07232] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
![]()
To
characterize the thermosensitive coil–globule transition in
atomistic detail, the conformational dynamics of linear polymer chains
of acrylamide-based polymers have been investigated at multiple temperatures.
Therefore, molecular dynamic simulations of 30mers of polyacrylamide
(AAm), poly-N-methylacrylamide (NMAAm), poly-N-ethylacrylamide (NEAAm), and poly-N-isopropylacrylamide
(NIPAAm) have been performed at temperatures ranging from 250 to 360
K for 2 μs. While two of the polymers are known to exhibit thermosensitivity
(NEAAm, NIPAAm), no thermosensitivity is observed for AAm and NMAAm
in aqueous solution. Our computer simulations consistently reproduce
these properties. To understand the thermosensitivity of the respective
polymers, the conformational ensembles at different temperatures have
been separated according to the coil–globule transition. The
coil and globule conformational ensembles were exhaustively analyzed
in terms of hydrogen bonding with the solvent, the change of the solvent
accessible surface, and enthalpic contributions. Surprisingly, independent
of different thermosensitive properties of the four polymers, the
surface affinity to water of coil conformations is higher than for
globule conformations. Therefore, polymer–solvent interactions
stabilize coil conformations at all temperatures. Nevertheless, the
enthalpic contributions alone cannot explain the differences in thermosensitivity.
This clearly implies that entropy is the distinctive factor for thermosensitivity.
With increasing side chain length, the lifetime of the hydrogen bonds
between the polymer surface and water is extended. Thus, we surmise
that a longer side chain induces a larger entropic penalty due to
immobilization of water molecules.
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Affiliation(s)
- Patrick K Quoika
- Institute of General, Inorganic and Theoretical Chemistry, and Centre of Molecular Biosciences University of Innsbruck, Innsbruck, A-6020 Austria
| | - Maren Podewitz
- Institute of General, Inorganic and Theoretical Chemistry, and Centre of Molecular Biosciences University of Innsbruck, Innsbruck, A-6020 Austria
| | - Yin Wang
- Institute of General, Inorganic and Theoretical Chemistry, and Centre of Molecular Biosciences University of Innsbruck, Innsbruck, A-6020 Austria
| | - Anna S Kamenik
- Institute of General, Inorganic and Theoretical Chemistry, and Centre of Molecular Biosciences University of Innsbruck, Innsbruck, A-6020 Austria
| | - Johannes R Loeffler
- Institute of General, Inorganic and Theoretical Chemistry, and Centre of Molecular Biosciences University of Innsbruck, Innsbruck, A-6020 Austria
| | - Klaus R Liedl
- Institute of General, Inorganic and Theoretical Chemistry, and Centre of Molecular Biosciences University of Innsbruck, Innsbruck, A-6020 Austria
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21
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Zhang X, Zong J, Meng D. A unified understanding of the cononsolvency of polymers in binary solvent mixtures. SOFT MATTER 2020; 16:7789-7796. [PMID: 32744548 DOI: 10.1039/d0sm00811g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The standard random phase approximation (RPA) model is applied to investigate the cononsolvency of polymers in mixtures of two good solvents. It is shown that in the RPA framework, the two types of cononsolvency behaviors reported in previous theoretical studies can be unified under the same concept of mean-field density correlations. The two types of cononsolvency are distinguished by the solvent composition at which maximum immiscibility is predicted to occur. The maximum immiscibility occurs with the cosolvent being the minor solvent if the driving mechanism is the preferential solvation of polymers. For the cononsolvency driven by the preferential mixing of solvents, the maximum immiscibility is predicted at a symmetric solvent composition. An interplay of the two driving forces gives rise to a reentrant behavior in which the cononsolvency of the two types switches from one to the other, through a "conventional" region where the overall solvent quality varies monotonically with the solvent composition. The RPA model developed in this work provides a unified analytical framework for understanding the conformational and solubility transition of polymers in multi-solvent mixtures. Such findings highlight the complex role played by the solvents in polymer solutions, a problem of fundamental and practical interest in diverse applications of materials science.
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Affiliation(s)
- Xiangyu Zhang
- The Swalm School of Chemical Engineering, Mississippi State University, Mississippi State, MS 39762, USA.
| | - Jing Zong
- The Swalm School of Chemical Engineering, Mississippi State University, Mississippi State, MS 39762, USA.
| | - Dong Meng
- The Swalm School of Chemical Engineering, Mississippi State University, Mississippi State, MS 39762, USA.
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22
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Narang P, de Oliveira TE, Venkatesu P, Netz PA. The role of osmolytes in the temperature-triggered conformational transition of poly(N-vinylcaprolactam): an experimental and computational study. Phys Chem Chem Phys 2020; 22:5301-5313. [PMID: 32096507 DOI: 10.1039/c9cp06683g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Biomedical industries are widely exploring the use of thermo-responsive polymers (TRPs) in the advanced development of drug delivery and in many other pharmaceutical applications. There is a great need to investigate the use of less toxic and more (bio-)compatible TRPs employing several additives, which could modify the conformational transition behavior of TRPs in aqueous solution. To move forward in this aspect, we have chosen the less toxic bio-based polymer poly(N-vinylcaprolactam) (PVCL) and three different methylamine-based osmolytes, trimethylamine N-oxide (TMAO), betaine and sarcosine, in order to investigate their particular interactions with the polymer segments in PVCL and therefore the corresponding changes in the thermo-responsive conformational behavior. Several biophysical techniques, UV-visible spectroscopy, fluorescence spectroscopy, dynamic light scattering (DLS) and laser Raman spectroscopy, as well as classical computer simulation methods such as molecular dynamics are employed in the current work. All the studied methylamines are found to favor the hydrophobic collapse of the polymer thus stabilizing the globular state of PVCL. Sarcosine is observed to cause the maximum decrease in lower critical solution temperature (LCST) of PVCL followed by TMAO and then betaine. The differences observed in the LCST values of PVCL in the presence of these molecules can be attributed to the different polymer-osmolyte interactions. The less sterically hindered N atom in the case of sarcosine causes a significant difference in the phase transition temperature values of PVCL compared to betaine and TMAO, where the nitrogen atom is buried by three methyl groups attached to it.
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Affiliation(s)
- Payal Narang
- Department of Chemistry, University of Delhi, Delhi-110007, India.
| | | | | | - Paulo A Netz
- Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
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23
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Characterization of conformational transition of polymers with low molecular weights in solutions by fluorescence resonance energy transfer. POLYMER 2020. [DOI: 10.1016/j.polymer.2020.122217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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24
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Molecular description of the coil-to-globule transition of Poly(N-isopropylacrylamide) in water/ethanol mixture at low alcohol concentration. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2019.111928] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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25
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Koochaki A, Reza Moghbeli M, Javan Nikkhah S. Effect of γ-substituted poly(ɛ-caprolactone) chain length on its coil-to-globule transition temperature in water: A molecular dynamics simulation study. Chem Phys 2019. [DOI: 10.1016/j.chemphys.2019.110506] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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26
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Podewitz M, Wang Y, Quoika PK, Loeffler JR, Schauperl M, Liedl KR. Coil-Globule Transition Thermodynamics of Poly( N-isopropylacrylamide). J Phys Chem B 2019; 123:8838-8847. [PMID: 31545046 DOI: 10.1021/acs.jpcb.9b06125] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Thermosensitive polymers such as poly(N-isopropylacrylamide) (PNIPAM) undergo a phase transition in aqueous solution from a random-coil structural ensemble to a globule structural ensemble at the lower critical solution temperature (LCST). Above this temperature, PNIPAM agglomerates and becomes insoluble, whereas it is soluble below the temperature. Thus, thermosensitive polymers represent essential targets for several applications, e.g., in drug delivery. Although their ability to change structure in response to a temperature alteration is highly relevant for industrial processes, their thermodynamic properties are mostly qualitatively understood, and the quantitative thermodynamic picture is still elusive. In this study, we used a combined atomistic molecular dynamics and well-tempered metadynamics simulation approach to estimate coil-globule transition thermodynamics. An isotactic 30-mer of PNIPAM was investigated over a broad temperature range between 200 and 360 K. The transition from the globule to the random-coil structure was observed with well-tempered metadynamics. For the first time, the free energy surface of PNIPAM was estimated and it is shown that the simulation results are in line with the experimentally observed thermosensitive behavior. Below the LCST, the random-coil ensemble represents the global energy minimum and is thermodynamically favored by 21 ± 9 kJ/mol compared to the globule ensemble; both are separated by a barrier of 49 ± 14 kJ/mol. In contrast, above the LCST, the globule ensemble is thermodynamically favored by 21 ± 8 kJ/mol over the random-coil ensemble. The barrier from random-coil to globule is 17 ± 10 kJ/mol.
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Affiliation(s)
- Maren Podewitz
- Institute of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences Innsbruck (CMBI) , University of Innsbruck , Innrain 80-82 , A-6020 Innsbruck , Austria
| | - Yin Wang
- Institute of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences Innsbruck (CMBI) , University of Innsbruck , Innrain 80-82 , A-6020 Innsbruck , Austria
| | - Patrick K Quoika
- Institute of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences Innsbruck (CMBI) , University of Innsbruck , Innrain 80-82 , A-6020 Innsbruck , Austria
| | - Johannes R Loeffler
- Institute of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences Innsbruck (CMBI) , University of Innsbruck , Innrain 80-82 , A-6020 Innsbruck , Austria
| | - Michael Schauperl
- Institute of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences Innsbruck (CMBI) , University of Innsbruck , Innrain 80-82 , A-6020 Innsbruck , Austria
| | - Klaus R Liedl
- Institute of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences Innsbruck (CMBI) , University of Innsbruck , Innrain 80-82 , A-6020 Innsbruck , Austria
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27
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Inoue M, Hayashi T, Hikiri S, Ikeguchi M, Kinoshita M. Mechanism of globule-to-coil transition of poly(N-isopropylacrylamide) in water: Relevance to cold denaturation of a protein. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111374] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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28
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Costanzo S, Scherz L, Floudas G, Pasquino R, Kröger M, Schlüter AD, Vlassopoulos D. Hybrid Dendronized Polymers as Molecular Objects: Viscoelastic Properties in the Melt. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01412] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Salvatore Costanzo
- Institute of Electronic Structure and Laser, Foundation for Research and Technology—Hellas, Heraklion 70013, Crete, Greece
- Department of Materials Science and Technology, University of Crete, Heraklion 71003, Crete, Greece
- DICMAPI, University of Naples, P.le Tecchio 80, Naples 80125, Italy
| | - Leon Scherz
- Polymer Chemistry and Polymer Physics, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - George Floudas
- Department of Physics, University of Ioannina, 45110 Ioannina, Greece
- Max Planck Institute for Polymer Research, 55128 Mainz, Germany
| | - Rossana Pasquino
- DICMAPI, University of Naples, P.le Tecchio 80, Naples 80125, Italy
| | - Martin Kröger
- Polymer Chemistry and Polymer Physics, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - A. Dieter Schlüter
- Polymer Chemistry and Polymer Physics, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Dimitris Vlassopoulos
- Institute of Electronic Structure and Laser, Foundation for Research and Technology—Hellas, Heraklion 70013, Crete, Greece
- Department of Materials Science and Technology, University of Crete, Heraklion 71003, Crete, Greece
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29
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Camara M, Liao H, Xu J, Zhang J, Swai R. Molecular dynamics study of the intercalation and conformational transition of poly (N-vinyl caprolactam), a thermosensitive polymer in hydrated Na-montmorillonite. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.121718] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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30
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Dalgicdir C, van der Vegt NFA. Improved Temperature Behavior of PNIPAM in Water with a Modified OPLS Model. J Phys Chem B 2019; 123:3875-3883. [PMID: 30990715 DOI: 10.1021/acs.jpcb.9b01644] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We test the OPLS/AA force field for a single PNIPAM 40-mer in aqueous solution using replica exchange molecular dynamics simulations and find that the force field fails to reproduce the experimental temperature behavior. To resolve this issue, we apply a modification on the partial charges previously suggested to reproduce the liquid-liquid phase separation of NIPAM aqueous solutions. The modified force field features stronger amide-water electrostatic interactions than the original OPLS model, predicts a weaker water-mediated monomer-monomer attraction, and reproduces the experimental coil-globule collapse enthalpy of PNIPAM in water. We revisit the cononsolvency problem of PNIPAM in methanol/water mixtures with the modified model and show that the dependence of the coil-globule collapse enthalpy on methanol concentration follows the experimental trend of the lower critical solution temperature. The calculations with the modified force field confirm that polymer dehydration is the determining factor for chain collapse in the cononsolvency regime.
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Affiliation(s)
- Cahit Dalgicdir
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie , Technische Universität Darmstadt , D-64287 Darmstadt , Germany
| | - Nico F A van der Vegt
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie , Technische Universität Darmstadt , D-64287 Darmstadt , Germany
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31
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Hou Y, Guo Y, Qian S, Khan H, Han G, Zhang W. A new thermoresponsive polymer of poly(N-acetoxylethyl acrylamide). POLYMER 2019. [DOI: 10.1016/j.polymer.2019.02.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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32
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Rovigatti L, Gnan N, Tavagnacco L, Moreno AJ, Zaccarelli E. Numerical modelling of non-ionic microgels: an overview. SOFT MATTER 2019; 15:1108-1119. [PMID: 30543246 PMCID: PMC6371763 DOI: 10.1039/c8sm02089b] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 11/26/2018] [Indexed: 05/03/2023]
Abstract
Microgels are complex macromolecules. These colloid-sized polymer networks possess internal degrees of freedom and, depending on the polymer(s) they are made of, can acquire a responsiveness to variations of the environment (temperature, pH, salt concentration, etc.). Besides being valuable for many practical applications, microgels are also extremely important to tackle fundamental physics problems. As a result, these last years have seen a rapid development of protocols for the synthesis of microgels, and more and more research has been devoted to the investigation of their bulk properties. However, from a numerical standpoint the picture is more fragmented, as the inherently multi-scale nature of microgels, whose bulk behaviour crucially depends on the microscopic details, cannot be handled at a single level of coarse-graining. Here we present an overview of the methods and models that have been proposed to describe non-ionic microgels at different length-scales, from the atomistic to the single-particle level. We especially focus on monomer-resolved models, as these have the right level of details to capture the most important properties of microgels, responsiveness and softness. We suggest that these microscopic descriptions, if realistic enough, can be employed as starting points to develop the more coarse-grained representations required to investigate the behaviour of bulk suspensions.
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Affiliation(s)
- Lorenzo Rovigatti
- Dipartimento di Fisica
, Sapienza Università di Roma
,
Piazzale A. Moro 2
, 00185 Roma
, Italy
.
- CNR-ISC
, Uos Sapienza
,
Piazzale A. Moro 2
, 00185 Roma
, Italy
.
| | - Nicoletta Gnan
- Dipartimento di Fisica
, Sapienza Università di Roma
,
Piazzale A. Moro 2
, 00185 Roma
, Italy
.
- CNR-ISC
, Uos Sapienza
,
Piazzale A. Moro 2
, 00185 Roma
, Italy
.
| | - Letizia Tavagnacco
- Dipartimento di Fisica
, Sapienza Università di Roma
,
Piazzale A. Moro 2
, 00185 Roma
, Italy
.
- CNR-ISC
, Uos Sapienza
,
Piazzale A. Moro 2
, 00185 Roma
, Italy
.
| | - Angel J. Moreno
- Centro de Física de Materiales (CSIC, UPV/EHU) and Materials Physics Center MPC
,
Paseo Manuel de Lardizabal 5
, 20018 San Sebastián
, Spain
- Donostia International Physics Center
,
Paseo Manuel de Lardizabal 4
, 20018 San Sebastian
, Spain
| | - Emanuela Zaccarelli
- Dipartimento di Fisica
, Sapienza Università di Roma
,
Piazzale A. Moro 2
, 00185 Roma
, Italy
.
- CNR-ISC
, Uos Sapienza
,
Piazzale A. Moro 2
, 00185 Roma
, Italy
.
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33
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Zhu PW, Chen L. Effects of cosolvent partitioning on conformational transitions and chain flexibility of thermoresponsive microgels. Phys Rev E 2019; 99:022501. [PMID: 30934277 DOI: 10.1103/physreve.99.022501] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Indexed: 06/09/2023]
Abstract
The conformational collapse of polymers in mixtures of two individually good solvents is an intriguing yet puzzling phenomenon termed cononsolvency. In this paper, the concept of the preferential adsorption of the cosolvent is combined with mean-field approaches to elaborate the cononsolvency effect of dimethylformamide (DMF) on the thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) microgels in aqueous solutions. We give a quantitative description concerning the effects of DMF preferential adsorption and partitioning on the reentrant transition of PNIPAM microgels below the lower critical solution temperature (LCST) of PNIPAM. While the DMF cononsolvency incurs the conformational collapse, the affinity of DMF molecules to PNIPAM chains becomes increasingly stronger, which reveals that the conformational collapse is decoupled from the solvent quality of DMF-water mixtures. Considering the chain elasticity, spatial constraints, and surface charge of microgels, we explore the cononsolvency effect on the persistence length quantifying the PNIPAM flexibility. Our analysis elucidates that, depending on chain length and temperature, the DMF cononsolvency-induced collapse of PNIPAM microgels leads to a remarkable increase in the persistent length below LCST, which is comparable to the experimental data regarding suspension mechanical properties of PNIPAM microgels in water above LCST.
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Affiliation(s)
- Peng-Wei Zhu
- Department of Materials Science and Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Luguang Chen
- Department of Chemical Engineering, Monash University, Clayton, VIC 3800, Australia
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34
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Kanduč M, Kim WK, Roa R, Dzubiella J. Transfer Free Energies and Partitioning of Small Molecules in Collapsed PNIPAM Polymers. J Phys Chem B 2019; 123:720-728. [PMID: 30576139 DOI: 10.1021/acs.jpcb.8b10134] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A central quantity in the design of functional hydrogels used as nanocarrier systems, for instance, for drug delivery or adaptive nanocatalysis, is the partition ratio, which quantifies the uptake of a molecular substance by the polymer matrix. By employing all-atom molecular dynamics simulations, we study the solvation and partitioning (with respect to bulk water) of small subnanometer-sized solutes in a dense matrix of collapsed poly( N-isopropylacrylamide) (PNIPAM) polymers above the lower critical solution temperature in aqueous solution. We examine the roles of the solute's polarity and its size on the solubility properties in the thermoresponsive polymer. We show that the transfer free energies of nonpolar solutes from bulk water into the polymer are favorable and scale in a good approximation with the solute's surface area. Even for small solute size variation, partitioning can vary over orders of magnitude. A polar nature of the solute, on the other hand, generally opposes the transfer, at least for alkyl solutes. Finally, we find a strong correlation between the transfer free energies in the gel and the adsorption free energies on a single extended polymer chain, which enables us to relate the partition ratios in the swollen and collapsed state of a PNIPAM gel.
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Affiliation(s)
- Matej Kanduč
- Research Group for Simulations of Energy Materials , Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner-Platz 1 , D-14109 Berlin , Germany.,Jožef Stefan Institute , Jamova 39 , SI-1001 Ljubljana , Slovenia
| | - Won Kyu Kim
- Research Group for Simulations of Energy Materials , Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner-Platz 1 , D-14109 Berlin , Germany
| | - Rafael Roa
- Departamento de Física Aplicada I, Facultad de Ciencias , Universidad de Málaga , Campus de Teatinos s/n , E-29071 Málaga , Spain
| | - Joachim Dzubiella
- Research Group for Simulations of Energy Materials , Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn-Meitner-Platz 1 , D-14109 Berlin , Germany.,Applied Theoretical Physics-Computational Physics, Physikalisches Institut , Albert-Ludwigs-Universität Freiburg , Hermann-Herder Strasse 3 , D-79104 Freiburg , Germany
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35
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Otto DP, Combrinck J, Otto A, Tiedt LR, de Villiers MM. Dissipative Particle Dynamics Investigation of the Transport of Salicylic Acid through a Simulated In Vitro Skin Permeation Model. Pharmaceuticals (Basel) 2018; 11:ph11040134. [PMID: 30563088 PMCID: PMC6316323 DOI: 10.3390/ph11040134] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 11/24/2018] [Accepted: 11/29/2018] [Indexed: 11/16/2022] Open
Abstract
Permeation models are often used to determine diffusion properties of a drug through a membrane as it is released from a delivery system. In order to circumvent problematic in vivo studies, diffusion studies can be performed in vitro, using (semi-)synthetic membranes. In this study salicylic acid permeation was studied, employing a nitrocellulose membrane. Both saturated and unsaturated salicylic acid solutions were studied. Additionally, the transport of salicylic acid through the nitrocellulose membrane was simulated by computational modelling. Experimental observations could be explained by the transport mechanism that was revealed by dissipative particle dynamics (DPD) simulations. The DPD model was developed with the aid of atomistic scale molecular dynamics (AA-MD). The choice of a suitable model membrane can therefore, be predicted by AA-MD and DPD simulations. Additionally, the difference in the magnitude of release from saturated and unsaturated salicylic acid and solutions could also be observed with DPD. Moreover, computational studies can reveal hidden variables such as membrane-permeant interaction that cannot be measured experimentally. A recommendation is made for the development of future model permeation membranes is to incorporate computational modelling to aid the choice of model.
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Affiliation(s)
- Daniel P Otto
- Research Focus Area for Chemical Resource Beneficiation, Laboratory for Analytical Services, North-West University, 11 Hoffman Street, Potchefstroom 2531, South Africa.
| | - Johann Combrinck
- Centre of Excellence for Pharmaceutical Sciences, North-West University, 11 Hoffman Street, Potchefstroom 2531, South Africa.
| | - Anja Otto
- Centre of Excellence for Pharmaceutical Sciences, North-West University, 11 Hoffman Street, Potchefstroom 2531, South Africa.
| | - Louwrens R Tiedt
- Research Focus Area for Chemical Resource Beneficiation, Laboratory for Electron Microscopy, North-West University, 11 Hoffman Street, Potchefstroom 2531, South Africa.
| | - Melgardt M de Villiers
- School of Pharmacy, University of Wisconsin⁻Madison, 777 Highland Avenue, Madison, WI 53705, USA.
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36
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Moshref-Javadi M, Simon GP, Medhekar NV. Atomistic insights into the adsorption and stimuli-responsive behavior of poly(N-isopropylacrylamide)-graphene hybrid systems. Phys Chem Chem Phys 2018; 20:28592-28599. [PMID: 30406254 DOI: 10.1039/c8cp04191a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Non-covalent functionalization of graphene materials with responsive polymers is a promising approach for synthesizing new, hybrid composites with improved dispersibility and functional properties. However, the interplay between various components of the hybrid systems, their structural configurations, and stimuli-responsive behavior are not yet well understood at the atomic level. Here, we investigate the temperature-responsive behavior of physisorbed poly(N-isopropylacrylamide) (PNIPAM) on to graphene (G) and graphene oxide (GO) sheets in aqueous solution using large scale molecular dynamics simulations. It was observed that PNIPAM can be spontaneously anchored to the surfaces of both G and GO at 290 K with a macromolecular coil shape. However, the configuration of PNIPAM on G is markedly different in comparison with that on GO, leading to its distinct thermoresponsive behavior. Specifically, the adsorption on G gives rise to an increase in the temperature of the coil-to-globule transition when compared to the native polymer, the origin of which can be interpreted in terms of the interactions and the solvation behavior. The results obtained here are of significance to the design and manipulation of graphene-based stimuli-responsive hybrid systems with optimal functional properties.
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Affiliation(s)
- Mahdi Moshref-Javadi
- Department of Materials Science and Engineering, Monash University, Clayton, VIC 3800, Australia.
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37
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Szlag VM, Jung S, Rodriguez RS, Bourgeois M, Bryson S, Schatz GC, Reineke TM, Haynes CL. Isothermal Titration Calorimetry for the Screening of Aflatoxin B1 Surface-Enhanced Raman Scattering Sensor Affinity Agents. Anal Chem 2018; 90:13409-13418. [DOI: 10.1021/acs.analchem.8b03221] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Victoria M. Szlag
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Seyoung Jung
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Rebeca S. Rodriguez
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Marc Bourgeois
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Samuel Bryson
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - George C. Schatz
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Theresa M. Reineke
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Christy L. Haynes
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
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38
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A molecular dynamics simulation scenario for studying solvent-mediated interactions of polymers and application to thermoresponse of poly(N-isopropylacrylamide) in water. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.07.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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39
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Kanduč M, Kim WK, Roa R, Dzubiella J. Selective Molecular Transport in Thermoresponsive Polymer Membranes: Role of Nanoscale Hydration and Fluctuations. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00735] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Matej Kanduč
- Research Group for Simulations of Energy Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
| | - Won Kyu Kim
- Research Group for Simulations of Energy Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
| | - Rafael Roa
- Research Group for Simulations of Energy Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
- Departamento de Física Aplicada I, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, E-29071 Málaga, Spain
| | - Joachim Dzubiella
- Research Group for Simulations of Energy Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder Strasse 3, D-79104 Freiburg, Germany
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40
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Korolovych VF, Erwin A, Stryutsky A, Lee H, Heller WT, Shevchenko VV, Bulavin LA, Tsukruk VV. Thermally Responsive Hyperbranched Poly(ionic liquid)s: Assembly and Phase Transformations. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b00845] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Volodymyr F. Korolovych
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Andrew Erwin
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Alexandr Stryutsky
- Institute of Macromolecular Chemistry, National Academy of Sciences of Ukraine, Kharkivske Shosse 48, Kyiv 02160, Ukraine
| | - Hansol Lee
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - William T. Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Valery V. Shevchenko
- Institute of Macromolecular Chemistry, National Academy of Sciences of Ukraine, Kharkivske Shosse 48, Kyiv 02160, Ukraine
| | - Leonid A. Bulavin
- Taras Shevchenko
National University of Kyiv, Volodymyrska Str. 64, 01601 Kyiv, Ukraine
| | - Vladimir V. Tsukruk
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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41
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Adroher-Benítez I, Moncho-Jordá A, Odriozola G. Conformation change of an isotactic poly (N-isopropylacrylamide) membrane: Molecular dynamics. J Chem Phys 2018; 146:194905. [PMID: 28527458 DOI: 10.1063/1.4983525] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this work, isotactic Poly (N-Isopropylacrylamide)-PNIPAM-in neat water and in electrolyte solutions is studied by means of molecular dynamics simulations. This is done for an infinitely diluted oligomer and for an assembly of several PNIPAM chains arranged into a planar membrane configuration with a core-shell morphology. We employed two different force fields, AMBER (assisted model building with energy refinement) and OPLS-AA (all atom - optimized potentials for liquid simulations) in combination with extended simple point charge water. Despite the more water insoluble character of isotactic oligomers, our results support the existence of a coil to globule transition for the isolated 30-mer. This may imply the existence of an oligomer rich phase of coil-like structures in equilibrium with a water rich phase for temperatures close but below the coil to globule transition temperature, TΘ. However, the obtained coil structure is much more compact than that corresponding to the syndiotactic chain. Our estimations of TΘ are (308±5) K and (303±5) K for AMBER and OPLS-AA, respectively. The membrane configuration allows one to include chain-chain interactions, to follow density profiles of water, polymer, and solutes, and accessing the membrane-water interface tension. Results show gradual shrinking and swelling of the membrane by switching temperature above and below TΘ, as well as the increase and decrease of the membrane-water interface tension. Finally, concentration profiles for 1M NaCl and 1M NaI electrolytes are shown, depicting a strong salting-out effect for NaCl and a much lighter effect for NaI, in good qualitative agreement with experiments.
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Affiliation(s)
- Irene Adroher-Benítez
- Departamento de Física Aplicada e Instituto Carlos I de Física Teórica y Computacional, Facultad de Ciencias, Universidad de Granada, Campus Fuentenueva S/N, 18071 Granada, Spain
| | - Arturo Moncho-Jordá
- Departamento de Física Aplicada e Instituto Carlos I de Física Teórica y Computacional, Facultad de Ciencias, Universidad de Granada, Campus Fuentenueva S/N, 18071 Granada, Spain
| | - Gerardo Odriozola
- Área de Física de Procesos Irreversibles, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana, Ave. San Pablo 180 Col., Reynosa-Tamaulipas, 02200 Ciudad de México, Mexico
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42
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De Silva CC, Leophairatana P, Ohkuma T, Koberstein JT, Kremer K, Mukherji D. Sequence transferable coarse-grained model of amphiphilic copolymers. J Chem Phys 2018; 147:064904. [PMID: 28810779 DOI: 10.1063/1.4997638] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Polymer properties are inherently multi-scale in nature, where delicate local interaction details play a key role in describing their global conformational behavior. In this context, deriving coarse-grained (CG) multi-scale models for polymeric liquids is a non-trivial task. Further complexities arise when dealing with copolymer systems with varying microscopic sequences, especially when they are of amphiphilic nature. In this work, we derive a segment-based generic CG model for amphiphilic copolymers consisting of repeat units of hydrophobic (methylene) and hydrophilic (ethylene oxide) monomers. The system is a simulation analogue of polyacetal copolymers [S. Samanta et al., Macromolecules 49, 1858 (2016)]. The CG model is found to be transferable over a wide range of copolymer sequences and also to be consistent with existing experimental data.
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Affiliation(s)
| | | | - Takahiro Ohkuma
- Central Research Division, Bridgestone Corporation, Kodaira, Tokyo 187-8531, Japan
| | - Jeffrey T Koberstein
- Department of Chemical Engineering, Columbia University, Columbia, New York 10027, USA
| | - Kurt Kremer
- Max-Planck Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
| | - Debashish Mukherji
- Max-Planck Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
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43
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Tavagnacco L, Zaccarelli E, Chiessi E. On the molecular origin of the cooperative coil-to-globule transition of poly(N-isopropylacrylamide) in water. Phys Chem Chem Phys 2018; 20:9997-10010. [PMID: 29619464 PMCID: PMC5932979 DOI: 10.1039/c8cp00537k] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The cooperativity of PNIPAM coil-to-globule transition in water arises from the structuring of solvent in proximity to hydrophobic groups.
By means of atomistic molecular dynamics simulations we investigate the behaviour of poly(N-isopropylacrylamide), PNIPAM, in water at temperatures below and above the lower critical solution temperature (LCST), including the undercooled regime. The transition between water soluble and insoluble states at the LCST is described as a cooperative process involving an intramolecular coil-to-globule transition preceding the aggregation of chains and the polymer precipitation. In this work we investigate the molecular origin of such cooperativity and the evolution of the hydration pattern in the undercooled polymer solution. The solution behaviour of an atactic 30-mer at high dilution is studied in the temperature interval from 243 to 323 K with a favourable comparison to available experimental data. In the water soluble states of PNIPAM we detect a correlation between polymer segmental dynamics and diffusion motion of bound water, occurring with the same activation energy. Simulation results show that below the coil-to-globule transition temperature PNIPAM is surrounded by a network of hydrogen bonded water molecules and that the cooperativity arises from the structuring of water clusters in proximity to hydrophobic groups. Differently, the perturbation of the hydrogen bond pattern involving water and amide groups occurs above the transition temperature. Altogether these findings reveal that even above the LCST PNIPAM remains largely hydrated and that the coil-to-globule transition is related with a significant rearrangement of the solvent in the proximity of the surface of the polymer. The comparison between the hydrogen bonding of water in the surrounding of PNIPAM isopropyl groups and in the bulk displays a decreased structuring of solvent at the hydrophobic polymer–water interface across the transition temperature, as expected because of the topological extension along the chain of such interface. No evidence of an upper critical solution temperature behaviour, postulated in theoretical and thermodynamics studies of PNIPAM aqueous solution, is observed in the low temperature domain.
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Affiliation(s)
- L Tavagnacco
- CNR-ISC, Uos Sapienza, Piazzale A. Moro 2, 00185 Roma, Italy
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44
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de Oliveira TE, Marques CM, Netz PA. Molecular dynamics study of the LCST transition in aqueous poly(N-n-propylacrylamide). Phys Chem Chem Phys 2018; 20:10100-10107. [PMID: 29589029 DOI: 10.1039/c8cp00481a] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The breadth of technological applications of smart polymers relies on the possibility of tuning their molecular structure to respond to external stimuli. In this context, N-substituted acrylamide-based polymers are widely studied thermoresponsive polymers. Poly(N-n-propylacrylamide) (PNnPAm), which is a structural isomer of the poly(N-isopropylacrylamide) (PNIPAm) exhibits however, a lower phase transition in aqueous solution. In this work, we use all-atom molecular dynamics simulations of PNnPAm in aqueous solutions to study, from a microscopic point-of-view, the influence of chain size and concentration on the LCST of PNnPAm. Our analysis shows that the collapse of a single oligomer of PNnPAm upon heating is dependent on the chain length and corresponds to a complex interplay between hydration and intermolecular interactions. Analysis of systems with multiple chains shows an aggregation of PNnPAm chains above the LCST.
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Affiliation(s)
- Tiago E de Oliveira
- Institut Charles Sadron, Université de Strasbourg, CNRS, Strasbourg, France.
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45
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Asadujjaman A, Espinosa de Oliveira T, Mukherji D, Bertin A. Polyacrylamide "revisited": UCST-type reversible thermoresponsive properties in aqueous alcoholic solutions. SOFT MATTER 2018; 14:1336-1343. [PMID: 29372224 DOI: 10.1039/c7sm02424j] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Combining experiments and all-atom molecular dynamics simulations, we study the conformational behavior of polyacrylamide (PAM) in aqueous alcohol mixtures over a wide range of temperatures. This study shows that even when the microscopic interaction is dictated by hydrogen bonding, unlike its counterparts that present a lower critical solution temperature (LCST), PAM shows a counterintuitive tunable upper critical solution temperature (UCST)-type phase transition in water/alcohol mixtures that was not reported before. The phase transition temperature was found to be tunable between 4 and 60 °C by the type and concentration of alcohol in the mixture as well as by the solution concentration and molecular weight of the polymer. In addition, molecular dynamics simulations confirmed a UCST-like behaviour of the PAM in aqueous alcoholic solutions. Additionally, it was observed that the PAM is more swollen in pure alcohol solutions than in 80% alcoholic solutions due to θ-like behaviour. Additionally, in the globular state, the size of the aggregates was found to increase with increasing solvent hydrophobicity and polymer concentration of the solutions. Above its phase transition temperature, PAM might be present as individual polymer chains in the coil state (≤10 nm). As PAM is a widespread polymer in many biomedical applications (gel electrophoresis, etc.), this finding could be of high relevance for many more practical applications in high performance pharmaceuticals and/or sensors.
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Affiliation(s)
- Asad Asadujjaman
- German Federal Institute for Materials Research and Testing (BAM), Dpt. 6. Materials Protection and Surface Technologies, Unter den Eichen 87, 12205 Berlin, Germany.
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46
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Paradossi G, Chiessi E. Solution behaviour of poly(N-isopropylacrylamide) stereoisomers in water: a molecular dynamics simulation study. Phys Chem Chem Phys 2018; 19:11892-11903. [PMID: 28436518 DOI: 10.1039/c7cp00808b] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The water affinity of poly(N-isopropylacrylamide), PNIPAM, is tuned by tacticity, since the hydrophobicity rises with the increase of the degree of isotacticity. On the basis of this experimental evidence, atomistic molecular dynamics simulations of pairs of PNIPAM stereoisomers in 1.6% w/w polymer aqueous solution, a condition intermediate between the dilute and semidilute regimes, were carried out to comparatively investigate the solution behaviour and hydration of atactic and isotactic-rich PNIPAMs, both below and above the lower critical solution temperature, LCST. 30-mers with contents of meso dyads, m, of 45% and 59%, built assuming a Bernoullian dyad distribution, are used as models since their stereochemical composition corresponds to that of experimentally characterized PNIPAM stereoisomers. The simulation results at 283 K, below the LCST, show a slight influence of tacticity on the chain size, but a higher propensity for inter-chain association of the meso-dyad-rich system, in agreement with the experimental results. Junctions between chains are formed because of hydrophobic interactions and are stabilized by a layer of hydrogen bonded water molecules, whose mobility is reduced as compared to that observed for the same meso-dyad-rich stereoisomer at infinite dilution. At 323 K, above the LCST, simulations detect both the coil-globule transition and the aggregation of chains. Under these conditions, the influence of tacticity on the characteristics of PNIPAM aggregate is negligible.
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Affiliation(s)
- G Paradossi
- Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica I, 00133 Rome, Italy.
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47
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Kanduč M, Chudoba R, Palczynski K, Kim WK, Roa R, Dzubiella J. Selective solute adsorption and partitioning around single PNIPAM chains. Phys Chem Chem Phys 2018; 19:5906-5916. [PMID: 28176999 DOI: 10.1039/c6cp08366h] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Thermoresponsive polymer architectures have become integral building blocks of 'smart' functional materials in modern applications. For a large range of developments, e.g. for drug delivery or nanocatalytic carrier systems, the selective adsorption and partitioning of molecules (ligands or reactants) inside the polymeric matrix are key processes that have to be controlled and tuned for the desired material function. In order to gain insights into the nanoscale structure and binding details in such systems, we here employ molecular dynamics simulations of the popular poly(N-isopropylacrylamide) (PNIPAM) polymer in explicit water in the presence of various representative solute types with a focus on aromatic model reactants. We study a single polymer chain and explore the influence of its elongation, stereochemistry, and temperature on the solute binding affinities. While we find that the excess adsorption generally increases with the size of the solute, the temperature-dependent affinity to the chain is highly solute specific and has a considerable dependence on the polymer elongation (i.e. polymer swelling state). We elucidate the molecular mechanisms of the selective binding in detail and eventually present how the results can be extrapolated to macroscopic partitioning of the solutes in swollen polymer architectures, such as hydrogels.
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Affiliation(s)
- Matej Kanduč
- Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany.
| | - Richard Chudoba
- Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany. and Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489 Berlin, Germany
| | - Karol Palczynski
- Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany.
| | - Won Kyu Kim
- Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany.
| | - Rafael Roa
- Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany.
| | - Joachim Dzubiella
- Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany. and Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489 Berlin, Germany
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48
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Narang P, Venkatesu P. Unravelling the role of polyols with increasing carbon chain length and OH groups on the phase transition behavior of PNIPAM. NEW J CHEM 2018. [DOI: 10.1039/c8nj02510j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In advanced applications of pharmaceutical, agricultural and biomedical research, thermoresponsive polymers (TRPs) are potential candidates which show conformational transitions at given temperatures.
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Affiliation(s)
- Payal Narang
- Department of Chemistry
- University of Delhi
- Delhi – 110 007
- India
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49
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Futscher MH, Philipp M, Müller-Buschbaum P, Schulte A. The Role of Backbone Hydration of Poly(N-isopropyl acrylamide) Across the Volume Phase Transition Compared to its Monomer. Sci Rep 2017; 7:17012. [PMID: 29208941 PMCID: PMC5717149 DOI: 10.1038/s41598-017-17272-7] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/22/2017] [Indexed: 11/08/2022] Open
Abstract
Thermo-responsive polymers undergo a reversible coil-to-globule transition in water after which the chains collapse and aggregate into bigger globules when passing to above its lower critical solution temperature (LCST). The hydrogen bonding with the amide groups in the side chains has to be contrasted with the hydration interaction of the hydrophobic main-chain hydrocarbons. In the present investigation we study molecular changes in the polymer poly(N-isopropyl acrylamide) (PNIPAM) and in its monomer N-isopropyl acrylamide (NIPAM) in solution across the LCST transition. Employing Fourier-transform infrared spectroscopy we probe changes in conformation and hydrogen bonding. We observe a nearly discontinuous shift of the peak frequencies and areas of vibrational bands across the LCST transition for PNIPAM whereas NIPAM exhibits a continuous linear change with temperature. This supports the crucial role of the polymer backbone with respect to hydration changes in the amide group in combination with cooperative interactions of bound water along the backbone chain.
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Affiliation(s)
- Moritz H Futscher
- Technische Universität München, Physik-Department, Lehrstuhl für Funktionelle Materialien, James-Franck-Str. 1, 85748, Garching, Germany
| | - Martine Philipp
- Technische Universität München, Physik-Department, Lehrstuhl für Funktionelle Materialien, James-Franck-Str. 1, 85748, Garching, Germany
| | - Peter Müller-Buschbaum
- Technische Universität München, Physik-Department, Lehrstuhl für Funktionelle Materialien, James-Franck-Str. 1, 85748, Garching, Germany
| | - Alfons Schulte
- University of Central Florida, Department of Physics and College of Optics and Photonics, 4111 Libra Drive, Orlando, FL, 32817-2385, United States.
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50
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Boţan V, Ustach VD, Leonhard K, Faller R. Development and Application of a Coarse-Grained Model for PNIPAM by Iterative Boltzmann Inversion and Its Combination with Lattice Boltzmann Hydrodynamics. J Phys Chem B 2017; 121:10394-10406. [PMID: 29072459 DOI: 10.1021/acs.jpcb.7b07818] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The polymer poly(N-isopropylacrylamide) (PNIPAM) is studied using a novel combination of multiscale modeling methodologies. We develop an iterative Boltzmann inversion potential of concentrated PNIPAM solutions and combine it with lattice Boltzmann as a Navier-Stokes equation solver for the solvent. We study in detail the influence of the methodology on statics and dynamics of the system. The combination is successful and significantly simpler and faster than other mapping techniques for polymer solution while keeping the correct hydrodynamics. The model can semiquantitatively describe the correct phase behavior and polymer dynamics.
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Affiliation(s)
- Vitalie Boţan
- Lehrstuhl für technische Thermodynamik, RWTH Aachen University , Schinkelstr. 8, 52062 Aachen, Germany
| | - Vincent D Ustach
- Department of Chemical Engineering, University of California, Davis , Davis, California 95616, United States
| | - Kai Leonhard
- Lehrstuhl für technische Thermodynamik, RWTH Aachen University , Schinkelstr. 8, 52062 Aachen, Germany
| | - Roland Faller
- Department of Chemical Engineering, University of California, Davis , Davis, California 95616, United States
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