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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
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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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2
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Stephan S, Dyga M, Alabd Alhafez I, Lenhard J, Urbassek HM, Hasse H. Reproducibility of atomistic friction computer experiments: a molecular dynamics simulation study. MOLECULAR SIMULATION 2021. [DOI: 10.1080/08927022.2021.1987430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Simon Stephan
- Laboratory of Engineering Thermodynamics (LTD), TU Kaiserslautern, Kaiserslautern, Germany
| | - Maximilian Dyga
- Laboratory of Engineering Thermodynamics (LTD), TU Kaiserslautern, Kaiserslautern, Germany
| | - Iyad Alabd Alhafez
- Physics Department and Research Center (OPTIMAS), TU Kaiserslautern, Kaiserslautern, Germany
| | - Johannes Lenhard
- Laboratory of Engineering Thermodynamics (LTD), TU Kaiserslautern, Kaiserslautern, Germany
| | - Herbert M. Urbassek
- Physics Department and Research Center (OPTIMAS), TU Kaiserslautern, Kaiserslautern, Germany
| | - Hans Hasse
- Laboratory of Engineering Thermodynamics (LTD), TU Kaiserslautern, Kaiserslautern, Germany
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3
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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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4
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Rick SW. Insights into the Thermal Response of a Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) Triblock Polymer in Water. J Phys Chem B 2021; 125:2167-2173. [PMID: 33606935 DOI: 10.1021/acs.jpcb.0c11279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A thermal responsive block copolymer made up of ethylene oxide (EO) and propylene oxide (PO) blocks was simulated with optimized atomistic potentials and enhanced sampling methods over a range of temperatures. The results for the L42 pluronic polymer (EO)4(PO)22(EO)4, which is known to undergo a transition in this temperature range, and the similarly sized (EO)30 polymer, which does not, are compared. The thermal responsive L42 polymers in a dilute solution tend to aggregate, and this tendency gets stronger as temperature increases. The poly(ethylene oxide) polymer shows no such tendency. The aggregation is stabilized by the hydrophobic contact of the propylene oxide methyl groups, which outweighs a small loss in hydrogen bonds between the ether oxygens and water.
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Affiliation(s)
- Steven W Rick
- Department of Chemistry, University of New Orleans, New Orleans, Louisiana 70148, United States
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5
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Zanatta M, Tavagnacco L, Buratti E, Chiessi E, Natali F, Bertoldo M, Orecchini A, Zaccarelli E. Atomic scale investigation of the volume phase transition in concentrated PNIPAM microgels. J Chem Phys 2020; 152:204904. [PMID: 32486676 DOI: 10.1063/5.0007112] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Combining elastic incoherent neutron scattering and differential scanning calorimetry, we investigate the occurrence of the volume phase transition (VPT) in very concentrated poly-(N-isopropyl-acrylamide) (PNIPAM) microgel suspensions, from a polymer weight fraction of 30 wt. % up to dry conditions. Although samples are arrested at the macroscopic scale, atomic degrees of freedom are equilibrated and can be probed in a reproducible way. A clear signature of the VPT is present as a sharp drop in the mean square displacement of PNIPAM hydrogen atoms obtained by neutron scattering. As a function of concentration, the VPT gets smoother as dry conditions are approached, whereas the VPT temperature shows a minimum at about 43 wt. %. This behavior is qualitatively confirmed by calorimetry measurements. Molecular dynamics simulations are employed to complement experimental results and gain further insights into the nature of the VPT, confirming that it involves the formation of an attractive gel state between the microgels. Overall, these results provide evidence that the VPT in PNIPAM-based systems can be detected at different time- and length-scales as well as under overcrowded conditions.
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Affiliation(s)
- M Zanatta
- Department of Physics, University of Trento, I-38123 Trento, Italy
| | - L Tavagnacco
- CNR-ISC and Department of Physics, Sapienza University of Rome, I-00185 Roma, Italy
| | - E Buratti
- CNR-ISC and Department of Physics, Sapienza University of Rome, I-00185 Roma, Italy
| | - E Chiessi
- Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, I-00133 Roma, Italy
| | - F Natali
- CNR-IOM, Operative Group in Grenoble (OGG), c/o Institut Laue Langevin, F-38042 Grenoble, France
| | - M Bertoldo
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara, Italy
| | - A Orecchini
- Department of Physics and Geology, University of Perugia, I-06123 Perugia, Italy
| | - E Zaccarelli
- CNR-ISC and Department of Physics, Sapienza University of Rome, I-00185 Roma, Italy
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6
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Rudyak VY, Kozhunova EY, Chertovich AV. Towards the realistic computer model of precipitation polymerization microgels. Sci Rep 2019; 9:13052. [PMID: 31506571 PMCID: PMC6737091 DOI: 10.1038/s41598-019-49512-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 08/06/2019] [Indexed: 11/08/2022] Open
Abstract
In this paper we propose a new method of coarse-grained computer simulations of the microgel formation in course of free radical precipitation polymerization. For the first time, we simulate the precipitation polymerization process from a dilute solution of initial components to a final microgel particle with coarse grained molecular dynamics, and compare it to the experimental data. We expect that our simulation studies of PNIPA-like microgels will be able to elucidate the subject of nucleation and growth kinetics and to describe in detail the network topology and structure. Performed computer simulations help to determine the characteristic phases of the growth process and show the necessity of prolongated synthesis for the formation of stable microgel particles. We demonstrate the important role of dangling ends in microgels, which occupy as much as 50% of its molecular mass and have previously unattended influence on the swelling behavior. The verification of the model is made by the comparison of collapse curves and structure factors between simulated and experimental systems, and high quality matching is achieved. This work could help to open new horizons in studies that require the knowledge of detailed and realistic structures of the microgel networks.
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Affiliation(s)
- Vladimir Yu Rudyak
- Lomonosov Moscow State University, Faculty of Physics, Moscow, 119991, Russia.
| | - Elena Yu Kozhunova
- Lomonosov Moscow State University, Faculty of Physics, Moscow, 119991, Russia
| | - Alexander V Chertovich
- Lomonosov Moscow State University, Faculty of Physics, Moscow, 119991, Russia
- Semenov Institute of Chemical Physics, Moscow, 119991, Russia
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7
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Casalini T, Perale G. From Microscale to Macroscale: Nine Orders of Magnitude for a Comprehensive Modeling of Hydrogels for Controlled Drug Delivery. Gels 2019; 5:E28. [PMID: 31096685 PMCID: PMC6631542 DOI: 10.3390/gels5020028] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 04/14/2019] [Accepted: 05/06/2019] [Indexed: 12/21/2022] Open
Abstract
Because of their inherent biocompatibility and tailorable network design, hydrogels meet an increasing interest as biomaterials for the fabrication of controlled drug delivery devices. In this regard, mathematical modeling can highlight release mechanisms and governing phenomena, thus gaining a key role as complementary tool for experimental activity. Starting from the seminal contribution given by Flory-Rehner equation back in 1943 for the determination of matrix structural properties, over more than 70 years, hydrogel modeling has not only taken advantage of new theories and the increasing computational power, but also of the methods offered by computational chemistry, which provide details at the fundamental molecular level. Simulation techniques such as molecular dynamics act as a "computational microscope" and allow for obtaining a new and deeper understanding of the specific interactions between the solute and the polymer, opening new exciting possibilities for an in silico network design at the molecular scale. Moreover, system modeling constitutes an essential step within the "safety by design" paradigm that is becoming one of the new regulatory standard requirements also in the field-controlled release devices. This review aims at providing a summary of the most frequently used modeling approaches (molecular dynamics, coarse-grained models, Brownian dynamics, dissipative particle dynamics, Monte Carlo simulations, and mass conservation equations), which are here classified according to the characteristic length scale. The outcomes and the opportunities of each approach are compared and discussed with selected examples from literature.
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Affiliation(s)
- Tommaso Casalini
- Biomaterials Laboratory, Institute for Mechanical Engineering and Materials Technology, SUPSI-University of Applied Sciences and Arts of Southern Switzerland, Via Cantonale 2C, Galleria 2, 6928 Manno, Switzerland.
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zurich, Switzerland.
| | - Giuseppe Perale
- Biomaterials Laboratory, Institute for Mechanical Engineering and Materials Technology, SUPSI-University of Applied Sciences and Arts of Southern Switzerland, Via Cantonale 2C, Galleria 2, 6928 Manno, Switzerland.
- Department of Surgical Sciences and Integrated Diagnostics, Orthopaedic Clinic-IRCCS Ospedale Policlinico San Martino, Faculty of Biomedical Sciences, University of Genova, Largo R. Benzi 10, 16132 Genova, Italy.
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