1
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Krott LB, Puccinelli T, Bordin JR. Core-softened colloid under extreme geometrical confinement. SOFT MATTER 2024; 20:4681-4691. [PMID: 38739368 DOI: 10.1039/d4sm00339j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
Geometrical constraints offer a promising strategy for assembling colloidal crystal structures that are not typically observed in bulk or under 2D conditions. Core-softened colloids, in particular, have emerged as versatile chemical building blocks with applications across various scientific and technological areas. In this study, we investigate the behavior of a core-softened model confined between two parallel walls. Employing molecular dynamics simulations, we analyze the system's response under extreme confinement, where only one or two layers of colloids are permitted. The system comprises particles modeled by a ramp-like potential confined within slit nanoslits created by two flat, purely repulsive walls with a lateral side L separated by a distance Lz. Through a systematic analysis of the phase behavior as Lz increases, or as the system undergoes decompression, for different values of L, we identified a mono-to-bilayer transition associated with changes in the colloidal structure. In the monolayer regime, we observed solid phases at lower densities than those observed in the 2D case. Importantly, we demonstrated that confinement at specific Lz values, allowing particle arrangement into two layers, can lead to the emergence of the square phase, which was not observed under monolayer or 2D conditions. By correlating thermodynamic, translational, and orientational ordering, as well as the dynamics of this confined colloidal system, our findings offer valuable insights into the utilization of geometrical constraints to induce and manipulate structural changes.
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Affiliation(s)
- Leandro B Krott
- Centro de Ciências, Tecnologias e Saúde, Campus Araranguá, Universidade Federal de Santa Catarina. Rua Pedro João Pereira, 150, CEP 88905120, Araranguá, SC, Brazil.
| | - Thiago Puccinelli
- Departamento de Física, Instituto de Física e Matemática, Universidade Federal de Pelotas. Caixa Postal 354, CEP 96001-970, Pelotas, RS, Brazil.
| | - José Rafael Bordin
- Departamento de Física, Instituto de Física e Matemática, Universidade Federal de Pelotas. Caixa Postal 354, CEP 96001-970, Pelotas, RS, Brazil.
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2
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Ampe A, Bandini E, Broeckhoven K, Lynen F. On-column modification for the creation of temperature-responsive stationary phases. Anal Chim Acta 2023; 1283:341961. [PMID: 37977785 DOI: 10.1016/j.aca.2023.341961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 11/19/2023]
Abstract
Temperature-responsive liquid chromatography (TRLC) offers an alternative for retention and selectivity optimisation in HPLC. This approach thereby exploits temperature gradients on stimuli-responsive stationary phases and forfeits the necessity for solvent gradients, allowing analyses to be performed using aqueous mobile phases. Consequently, it can be employed as a green alternative to reversed-phase separations. However, current production to obtain temperature-responsive columns inherently require dedicated column packing processes with polymer-modified particles. To facilitate the development of temperature-responsive phases, a flow-through modification procedure was developed allowing on-column modification of aminopropyl silica columns. Three columns were manufactured using this novel flow-through approach, which achieved identical column efficiencies compared to existing TRLC column. Demonstrating the possibility of bypassing the dedicated packing processes without losing efficiency. Additionally, it was observed that flow-through produced columns yielded higher retention at elevated temperatures despite their reduced carbon load. Further investigation of the carbon load revealed the presence of stationary phase gradients, whose influence was studied via novel developed retention experiments, which revealed a negligible change reduction in retention upon a change of polymer modification from 19.8% to 14.5%. However, further decrease from 14.5% to 12.3% resulted in a larger change. Interestingly, a further enhancement in apparent plate numbers was observed when operating the column under a reversed flow, yielding an increasing stationary phase gradient. This on-column modification procedure demonstrates the potential for modification of existing (commercial) packed columns to achieve temperature-responsive phases without loss of efficiency or retention. Thus, not only facilitating accessibility to temperature-responsive phases, but also aiding with development of further generations of temperature-responsive phases by removing the need for packing optimisation. Additionally, a novel experiment was set up to easily investigate the effect of inhomogeneous stationary phases retention.
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Affiliation(s)
- Adriaan Ampe
- Separation Science Group, Department of Organic and Macromolecular Chemistry, Krijgslaan 281, Ghent, Belgium
| | - Elena Bandini
- Separation Science Group, Department of Organic and Macromolecular Chemistry, Krijgslaan 281, Ghent, Belgium
| | - Ken Broeckhoven
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, Brussel, Belgium
| | - Frédéric Lynen
- Separation Science Group, Department of Organic and Macromolecular Chemistry, Krijgslaan 281, Ghent, Belgium.
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3
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Eygeris Y, Wang Q, Görke M, Grünwald M, Zharov I. Temperature-Responsive Nanoporous Membranes from Self-Assembly of Poly( N-isopropylacrylamide) Hairy Nanoparticles. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 37285651 DOI: 10.1021/acsami.3c05072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Nanoporous membranes play a critical role in numerous separations on laboratory and industrial scales, ranging from water treatment to biotechnology. However, few strategies exist that allow for the preparation of mechanically robust nanoporous membranes whose separation properties can be easily tuned. Here, we introduce a new family of tunable nanoporous membranes based on nanoparticles decorated with temperature-responsive polymer brushes. We prepared mechanically robust membranes from hairy nanoparticles (HNPs) carrying PNIPAM polymer brushes. We assembled the HNPs into thin films through pressure-driven deposition of nanoparticle suspensions and measured the permeability and filtration cutoff of these membranes at different temperatures. The membrane pore diameter at room temperature varied between 10 and 30 nm depending on the polymer length. The water permeability of these membranes could be controlled by temperature, with the effective pore diameter increasing by a factor of 3-6 (up to 100 nm) when the temperature was increased to 60 °C. The size selectivity of these membranes in the filtration of nanoparticles could also be attenuated by temperature. Molecular dynamics computer simulations of a coarse-grained HNP model show that temperature-sensitive pores sizes are consistent with our experimental results and reveal the polymer configurations responsible for the observed filtration membrane permeability. We expect that these membranes will be useful for separations and in the preparation of responsive microfluidic devices.
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Affiliation(s)
- Yulia Eygeris
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Qiaoyi Wang
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Marion Görke
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Michael Grünwald
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Ilya Zharov
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
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4
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Hemmatpour H, Haddadi-Asl V, Burgers TCQ, Yan F, Stuart MCA, Reker-Smit C, Vlijm R, Salvati A, Rudolf P. Temperature-responsive and biocompatible nanocarriers based on clay nanotubes for controlled anti-cancer drug release. NANOSCALE 2023; 15:2402-2416. [PMID: 36651239 DOI: 10.1039/d2nr06801j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Administration of temperature-responsive drug carriers that release anticancer drugs at high temperatures can benefit hyperthermia therapies because of the synergistic effect of anticancer drug molecules and high temperature on killing the cancer cells. In this study, we design and characterize a new temperature-responsive nanocarrier based on a naturally occurring and biocompatible clay mineral, halloysite nanotubes. Poly(N-isopropylacrylamide) brushes were grown on the surface of halloysite nanotubes using a combination of mussel-inspired dopamine polymerization and surface-initiated atom transfer radical polymerization. The chemical structure of the hybrid materials was investigated using X-ray photoelectron spectroscopy, thermogravimetric analysis and energy-dispersive X-ray spectroscopy. The hybrid material was shown to have a phase transition temperature of about 32 °C, corresponding to a 40 nm thick polymer layer surrounding the nanotubes. Cell studies suggested that grafting of poly(N-isopropylacrylamide) brushes on the polydopamine-modified halloysite nanotubes suppresses the cytotoxicity caused by the polydopamine interlayer and drug release studies on nanotubes loaded with doxorubicin showed that thanks to the poly(N-isopropylacrylamide) brushes a temperature-dependent drug release is observed. Finally, a fluorescent dye molecule was covalently attached to the polymer-grafted nanotubes and stimulated emission depletion nanoscopy was used to confirm the internalization of the nanotubes in HeLa cells.
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Affiliation(s)
- Hamoon Hemmatpour
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands.
- Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, P.O. Box 1587-4413, Tehran, Iran
| | - Vahid Haddadi-Asl
- Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, P.O. Box 1587-4413, Tehran, Iran
| | - Thomas C Q Burgers
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands.
| | - Feng Yan
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands.
| | - Marc C A Stuart
- Electron Microscopy, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Catharina Reker-Smit
- Department of Nanomedicine & Drug Targeting, Groningen Research Institute of Pharmacy, University of Groningen, A. Deusinglaan 1, Groningen, 9713AV, The Netherlands
| | - Rifka Vlijm
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands.
| | - Anna Salvati
- Department of Nanomedicine & Drug Targeting, Groningen Research Institute of Pharmacy, University of Groningen, A. Deusinglaan 1, Groningen, 9713AV, The Netherlands
| | - Petra Rudolf
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands.
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5
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Kuk K, Gregel L, Abgarjan V, Croonenbrock C, Hänsch S, Karg M. Micron-Sized Silica-PNIPAM Core-Shell Microgels with Tunable Shell-To-Core Ratio. Gels 2022; 8:gels8080516. [PMID: 36005117 PMCID: PMC9407347 DOI: 10.3390/gels8080516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 11/16/2022] Open
Abstract
Micron-sized hard core-soft shell hybrid microgels are promising model systems for studies of soft matter as they enable in-situ optical investigations and their structures/morphologies can be engineered with a great variety. Yet, protocols that yield micron-sized core-shell microgels with a tailorable shell-to-core size ratio are rarely available. In this work, we report on the one-pot synthesis protocol for micron-sized silica-poly(N-isopropylacrylamide) core-shell microgels that has excellent control over the shell-to-core ratio. Small-angle light scattering and microscopy of 2- and 3-dimensional assemblies of the synthesized microgels confirm that the produced microgels are monodisperse and suitable for optical investigation even at high packing fractions.
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Affiliation(s)
- Keumkyung Kuk
- Institut für Physikalische Chemie I: Kolloide und Nanooptik, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Lukas Gregel
- Institut für Physikalische Chemie I: Kolloide und Nanooptik, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Vahan Abgarjan
- Institut für Physikalische Chemie I: Kolloide und Nanooptik, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Caspar Croonenbrock
- Institut für Physikalische Chemie I: Kolloide und Nanooptik, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Sebastian Hänsch
- Center for Advanced Imaging, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Matthias Karg
- Institut für Physikalische Chemie I: Kolloide und Nanooptik, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
- Correspondence: ; Tel.: +49-211-81-12400
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6
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Enes da Silva MJ, Banerjee A, Lefferts L, Albanese JAF. In‐situ ATR‐IR Spectroscopy Reveals Complex Absorption‐Diffusion Dynamics in Model Polymer‐Membrane‐Catalyst Assemblies (PCMA). ChemCatChem 2022. [DOI: 10.1002/cctc.202101835] [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]
Affiliation(s)
- Maria Joao Enes da Silva
- University of Twente Institute for Nanotechnology: Universiteit Twente MESA+ Catalytic Processes and Materials Group NETHERLANDS
| | - Aayan Banerjee
- University of Twente Institute for Nanotechnology: Universiteit Twente MESA+ Catalytic Processes and Materials Group NETHERLANDS
| | - Leon Lefferts
- University of Twente Institute for Nanotechnology: Universiteit Twente MESA+ Catalytic Processes and Materials Group NETHERLANDS
| | - Jimmy Alexander Faria Albanese
- Universiteit Twente MESA+ Faculty of Science and Technology Drienerlolaan 5Meander ME361Netherlands 7522NB Enschede NETHERLANDS
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7
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Liguori A, Pandini S, Rinoldi C, Zaccheroni N, Pierini F, Focarete ML, Gualandi C. Thermo-active Smart Electrospun Nanofibers. Macromol Rapid Commun 2021; 43:e2100694. [PMID: 34962002 DOI: 10.1002/marc.202100694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 12/15/2021] [Indexed: 11/10/2022]
Abstract
The recent burst of research on smart materials is a clear evidence of the growing interest of the scientific community, industry, and society in the field. The exploitation of the great potential of stimuli-responsive materials for sensing, actuation, logic, and control applications is favored and supported by new manufacturing technologies, such as electrospinning, that allows to endow smart materials with micro- and nano-structuration, thus opening up additional and unprecedented prospects. In this wide and lively scenario, this article systematically reviews the current advances in the development of thermo-active electrospun fibers and textiles, sorting them, according to their response to the thermal stimulus. Hence, several platforms including thermo-responsive systems, shape memory polymers, thermo-optically responsive systems, phase change materials, thermoelectric materials, and pyroelectric materials, have been described and critically discussed. The difference in active species and outputs of the aforementioned categories has been highlighted, evidencing the transversal nature of temperature stimulus. Moreover, the potential of novel thermo-active materials has been pointed out, revealing how their development could take to utmost interesting achievements. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Anna Liguori
- Department of Chemistry "G. Ciamician" and INSTM UdR of Bologna, University of Bologna, via Selmi 2, Bologna, 40126, Italy
| | - Stefano Pandini
- Department of Chemistry "G. Ciamician" and INSTM UdR of Bologna, University of Bologna, via Selmi 2, Bologna, 40126, Italy
| | - Chiara Rinoldi
- Department of Chemistry "G. Ciamician" and INSTM UdR of Bologna, University of Bologna, via Selmi 2, Bologna, 40126, Italy
| | - Nelsi Zaccheroni
- Department of Chemistry "G. Ciamician" and INSTM UdR of Bologna, University of Bologna, via Selmi 2, Bologna, 40126, Italy
| | - Filippo Pierini
- Department of Chemistry "G. Ciamician" and INSTM UdR of Bologna, University of Bologna, via Selmi 2, Bologna, 40126, Italy
| | - Maria Letizia Focarete
- Department of Chemistry "G. Ciamician" and INSTM UdR of Bologna, University of Bologna, via Selmi 2, Bologna, 40126, Italy
| | - Chiara Gualandi
- Department of Chemistry "G. Ciamician" and INSTM UdR of Bologna, University of Bologna, via Selmi 2, Bologna, 40126, Italy
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8
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da Silva MJE, Lefferts L, Faria Albanese JA. N-isopropylacrylamide polymer brushes alter the micro-solvation environment during aqueous nitrite hydrogenation on Pd/Al2O3 catalyst. J Catal 2021. [DOI: 10.1016/j.jcat.2021.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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9
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Understanding the temperature induced aggregation of silica nanoparticles decorated with temperature-responsive polymers: Can a small step in the chemical structure make a giant leap for a phase transition? J Colloid Interface Sci 2021; 590:249-259. [PMID: 33548608 DOI: 10.1016/j.jcis.2021.01.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 01/14/2021] [Accepted: 01/17/2021] [Indexed: 11/20/2022]
Abstract
Temperature-responsive nanomaterials have gained increasing interest over the past decade due their ability to undergo conformational changes in situ, in response to a change in temperature. One class of temperature-responsive polymers are those with lower critical solution temperature, which phase separate in aqueous solution above a critical temperature. When these temperature-responsive polymers are grafted to a solid nanoparticle, a change in their surface properties occurs above this critical temperature, from hydrophilic to more hydrophobic, giving them a propensity to aggregate. This study explores the temperature induced aggregation of silica nanoparticles functionalised with two isomeric temperature-responsive polymers with lower critical solution temperature (LCST) behavior, namely poly(N-isopropyl acrylamide) (PNIPAM), and poly(2-n-propyl-2-oxazoline) (PNPOZ) with similar molecular weights (5000 Da) and grafting density. These nanoparticles exhibited striking differences in the temperature of aggregation, which is consistent with LCST of each polymer. Using a combination of small-angle neutron scattering (SANS) and dynamic light scattering (DLS), we probed subtle differences in the aggregation mechanism for PNIPAM- and PNPOZ-decorated silica nanoparticles. The nanoparticles decorated with PNIPAM and PNPOZ show similar aggregation mechanism that was independent of polymer structure, whereby aggregation starts by the formation of small aggregates. A further increase in temperature leads to interaction between these aggregates and results in full-scale aggregation and subsequent phase separation.
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10
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Zholdassov YS, Valles DJ, Uddin S, Korpanty J, Gianneschi NC, Braunschweig AB. Orthogonal Images Concealed Within a Responsive 6-Dimensional Hypersurface. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2100803. [PMID: 33876463 DOI: 10.1002/adma.202100803] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 02/24/2021] [Indexed: 06/12/2023]
Abstract
A photochemical printer, equipped with a digital micromirror device (DMD), leads to the rapid elucidation of the kinetics of the surface-initiated atom-transfer radical photopolymerization of N,N-dimethylacrylamide (DMA) and N-isopropylacrylamide (NIPAM) monomers. This effort reveals conditions where polymer brushes of identical heights can be grown from each monomer. With these data, hidden images are created that appear upon heating the substrate above the lower critical solution temperature (LCST) of polyNIPAM. By introducing a third monomer, methacryloxyethyl thiocarbamoyl rhodamine B, a second, orthogonal image appears upon UV-irradiation. With these studies, it is shown how a new photochemical printer accelerates discovery, creates arbitrary patterns, and addresses long-standing problems in brush polymer and surface chemistry. With this technology in hand a new method is demonstrated to encrypt data within hypersurfaces.
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Affiliation(s)
- Yerzhan S Zholdassov
- The Advanced Science Research Center at the Graduate Center of the City University of the New York, 85 St. Nicholas Terrace, New York, NY, 10031, USA
- Department of Chemistry, Hunter College, 695 Park Avenue, New York, NY, 10065, USA
- The Ph.D. Program in Chemistry, Graduate Center of the City University of New York, 365 Fifth Avenue, New York, NY, 10016, USA
| | - Daniel J Valles
- The Advanced Science Research Center at the Graduate Center of the City University of the New York, 85 St. Nicholas Terrace, New York, NY, 10031, USA
- Department of Chemistry, Hunter College, 695 Park Avenue, New York, NY, 10065, USA
- The Ph.D. Program in Chemistry, Graduate Center of the City University of New York, 365 Fifth Avenue, New York, NY, 10016, USA
| | - Samiha Uddin
- The Advanced Science Research Center at the Graduate Center of the City University of the New York, 85 St. Nicholas Terrace, New York, NY, 10031, USA
- Department of Chemistry, Hunter College, 695 Park Avenue, New York, NY, 10065, USA
| | - Joanna Korpanty
- Department of Chemistry, Northwestern University, Evanston, IL, 60208, USA
| | - Nathan C Gianneschi
- Department of Chemistry, Northwestern University, Evanston, IL, 60208, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Adam B Braunschweig
- The Advanced Science Research Center at the Graduate Center of the City University of the New York, 85 St. Nicholas Terrace, New York, NY, 10031, USA
- Department of Chemistry, Hunter College, 695 Park Avenue, New York, NY, 10065, USA
- The Ph.D. Program in Chemistry, Graduate Center of the City University of New York, 365 Fifth Avenue, New York, NY, 10016, USA
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11
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Li R, Cheng C, Wang Z, Gu X, Zhang C, Wang C, Liang X, Hu D. Conformational Stability of Poly (N-Isopropylacrylamide) Anchored on the Surface of Gold Nanoparticles. MATERIALS (BASEL, SWITZERLAND) 2021; 14:443. [PMID: 33477518 PMCID: PMC7831095 DOI: 10.3390/ma14020443] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 01/13/2021] [Accepted: 01/14/2021] [Indexed: 12/14/2022]
Abstract
To verify the temperature sensitive failure of poly (N-isopropylacrylamide) (PNIPAM) anchored on the surface of gold nanoparticles (AuNPs), the UV-Vis spectra with temperature variations of the following aqueous solutions respectively containing AuNPs-PNIPAM, Au-PNIPAM/PNIPAM, PNIPAM, in different media (including salt, ethanol, HCl and cetyltrimethylammoniumbromide (CTAB)), were systematically determined. The results indicated that the UV-Vis spectrum of AuNPs-PNIPAM suspension hardly changed even above the Lower Critical Solution Temperature (LCST) of PNIPAM, but that of Au-PNIPAM/PNIPAM sharply increased only in absorbance intensity. A possible mechanism of the failed temperature sensitivity of PNIPAM anchored on the surface of AuNPs was proposed. Being different from free PNIPAM molecules, a strong interaction exists among PNIPAM molecules anchored on the surface of AuNPs, restraining the change in conformation of PNIPAM. The temperature sensitivity of Au-PNIPAM/PNIPAM originates from the free PNIPAM molecules rather than the anchored PNIPAM one. The changing electrostatic interaction could effectively regulate the aggregation behavior of AuNPs-PNIPAM and enhance its sensitivity to temperature.
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Affiliation(s)
- Runmei Li
- Engineering Research Center of Historical and Cultural Heritage Protection, Ministry of Education, School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062, China; (R.L.); (C.C.); (Z.W.); (C.Z.); (C.W.)
| | - Cong Cheng
- Engineering Research Center of Historical and Cultural Heritage Protection, Ministry of Education, School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062, China; (R.L.); (C.C.); (Z.W.); (C.Z.); (C.W.)
| | - Zhuorui Wang
- Engineering Research Center of Historical and Cultural Heritage Protection, Ministry of Education, School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062, China; (R.L.); (C.C.); (Z.W.); (C.Z.); (C.W.)
| | - Xuefan Gu
- College of Chemistry and Chemical Engineering, Xi’an Shiyou University, Xi’an 710065, China;
| | - Caixia Zhang
- Engineering Research Center of Historical and Cultural Heritage Protection, Ministry of Education, School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062, China; (R.L.); (C.C.); (Z.W.); (C.Z.); (C.W.)
| | - Chen Wang
- Engineering Research Center of Historical and Cultural Heritage Protection, Ministry of Education, School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062, China; (R.L.); (C.C.); (Z.W.); (C.Z.); (C.W.)
| | - Xinyue Liang
- Institute of Industrial Hygiene of Ordnance Industry, Xi’an 710065, China;
| | - Daodao Hu
- Engineering Research Center of Historical and Cultural Heritage Protection, Ministry of Education, School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710062, China; (R.L.); (C.C.); (Z.W.); (C.Z.); (C.W.)
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12
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Moghaddam SZ, Thormann E. Surface forces and friction tuned by thermo-responsive polymer films. Curr Opin Colloid Interface Sci 2020. [DOI: 10.1016/j.cocis.2019.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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13
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Baliś A, Wolski K, Zapotoczny S. Thermoresponsive Polymer Gating System on Mesoporous Shells of Silica Particles Serving as Smart Nanocontainers. Polymers (Basel) 2020; 12:E888. [PMID: 32290489 PMCID: PMC7240617 DOI: 10.3390/polym12040888] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/06/2020] [Accepted: 04/08/2020] [Indexed: 01/12/2023] Open
Abstract
Spherical silica nanoparticles with solid cores and mesoporous shells (SCMS) were decorated with thermoresponsive polymer brushes that were shown to serve as macromolecular valves to control loading and unloading of a model dye within the mesopores. Thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) brushes were grafted from the surfaces of both solid core (SC) and SCMS particles of similar size using surface-initiated atom transfer radical polymerization. Both systems based on porous (SCMS-PNIPAM) and nonporous (SC-PNIPAM) particles were characterized using cryo-TEM, thermogravimetry and elemental analysis to determine the structure and composition of the decorated nanoparticles. The grafted PNIPAM brushes were found to be responsive to temperature changes enabling temperature-controlled gating of the pores. The processes of loading and unloading in the obtained systems were examined using a model fluorescent dye-rhodamine 6G. Polymer brushes in SCMS-PNIPAM systems were shown to serve as molecular valves enabling significant adsorption (loading) of the dye inside the pores with respect to the SC-PNIPAM (no pores) and SCMS (no valves) systems. The effective unloading of the fluorescent cargo molecules from the decorated nanoparticles was achieved in a water/methanol solution. The obtained SCMS-PNIPAM particles may be used as smart nanocontainers or nanoreactors offering also facile isolation from the suspension due to the presence of dense cores.
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Affiliation(s)
| | | | - Szczepan Zapotoczny
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland; (A.B.); (K.W.)
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van Duinen D, Butt HJ, Berger R. Two-Stage Collapse of PNIPAM Brushes: Viscoelastic Changes Revealed by an Interferometric Laser Technique. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:15776-15783. [PMID: 31633361 PMCID: PMC6943814 DOI: 10.1021/acs.langmuir.9b03205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 10/21/2019] [Indexed: 06/10/2023]
Abstract
Many temperature-responsive polymers exhibit a single-phase transition at the lower critical solution temperature (LCST). One exception is poly(N-isopropylacryamide) (PNIPAM). PNIPAM brush layers (51 ± 3 nm thick) that are end-grafted onto glass beads collapse in two stages. The viscoelastic changes of a PNIPAM brush layers were investigated with an interferometric laser method at different temperatures. This method is able to measure the two-stage collapse of beads coated with a polymer brush layer. When these beads are situated close to a hydrophilic glass surface, they exhibit Brownian motion. As this Brownian motion changes with temperature, the collapse of the polymer layer is revealed. The characteristic spectrum of the Brownian motion of beads is modeled by a damped harmonic oscillator, where the polymer layer acts as both spring and damping elements. The change of the Brownian motion spectrum with temperature indicates two transitions of the PNIPAM brush layer, one at 36 °C and one at 46 °C. We attribute the first transition to the LCST volume collapse of PNIPAM. Here, changes of the density and viscosity of the brush dominate. The second transition is dominated by a stiffening of the brush layer.
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Humphreys BA, Johnson EC, Wanless EJ, Webber GB. Poly( N-isopropylacrylamide) Response to Salt Concentration and Anion Identity: A Brush-on-Brush Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:10818-10830. [PMID: 31339320 DOI: 10.1021/acs.langmuir.9b00695] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The stability of poly(N-isopropylacrylamide) (PNIPAM) brush-modified colloidal silica particles was compared to asymmetric and symmetric PNIPAM brush direct force measurements in the presence of 1, 10, and 500 mM aqueous salt solution of KCl, KNO3, and KSCN between 10 and 45 °C. Dynamic light scattering measurements highlighted subtle variations in the salt-mediated thermoresponse, while atomic force microscopy (AFM) force curves between a bare silica or PNIPAM brush-modified colloid probe and a planar PNIPAM brush elucidated differences in brush interactions. The AFM force curves in the presence of KCl primarily revealed steric interactions between the surfaces, while KNO3 and KSCN solutions exhibited electrosteric interactions on approach as a function of the chaotropic nature of the ion and the solution concentration. The symmetric PNIPAM brush interaction highlighted significant variations between KCl and KSCN at 1 and 500 mM concentrations, while the approach and retraction force curves were relatively similar at 10 mM concentration. The combination of these techniques enabled the stability of PNIPAM brush-modified colloidal dispersions in the presence of electrolyte to be better understood with specific ion binding and the solution Debye length playing a significant role.
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Affiliation(s)
- Ben A Humphreys
- Priority Research Centre for Advanced Particle Processing and Transport , University of Newcastle , Callaghan , NSW 2308 , Australia
| | - Edwin C Johnson
- Priority Research Centre for Advanced Particle Processing and Transport , University of Newcastle , Callaghan , NSW 2308 , Australia
| | - Erica J Wanless
- Priority Research Centre for Advanced Particle Processing and Transport , University of Newcastle , Callaghan , NSW 2308 , Australia
| | - Grant B Webber
- Priority Research Centre for Advanced Particle Processing and Transport , University of Newcastle , Callaghan , NSW 2308 , Australia
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