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Terada E, Isono T, Satoh T, Yamamoto T, Kakuchi T, Sato S. All-Atom Molecular Dynamics Simulations of the Temperature Response of Poly(glycidyl ether)s with Oligooxyethylene Side Chains Terminated with Alkyl Groups. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:nano13101628. [PMID: 37242043 DOI: 10.3390/nano13101628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/09/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023]
Abstract
Recently, experimental investigations of a class of temperature-responsive polymers tethered to oligooxyethylene side chains terminated with alkyl groups have been conducted. In this study, aqueous solutions of poly(glycidyl ether)s (PGE) with varying numbers of oxyethylene units, poly(methyl(oligooxyethylene)n glycidyl ether) (poly(Me(EO)nGE)), and poly(ethyl(oligooxyethylene)n glycidyl ether) (poly(Et(EO)nGE) (n = 0, 1, and 2) were investigated by all-atom molecular dynamics simulations, focusing on the thermal responses of their chain extensions, the recombination of intrapolymer and polymer-water hydrogen bonds, and water-solvation shells around the alkyl groups. No clear relationship was established between the phase-transition temperature and the polymer-chain extensions unlike the case for the coil-globule transition of poly(N-isopropylacrylamide). However, the temperature response of the first water-solvation shell around the alkyl group exhibited a notable correlation with the phase-transition temperature. In addition, the temperature at which the hydrophobic hydration shell strength around the terminal alkyl group equals the bulk water density (TCRP) was slightly lower than the cloud point temperature (TCLP) for the methyl-terminated poly(Me(EO)nGE) and slightly higher for the ethyl-terminated poly(Et(EO)nGE). It was concluded that the polymer-chain fluctuation affects the relationship between TCRP and TCLP.
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Affiliation(s)
- Erika Terada
- Graduate School of Chemical Science and Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Takuya Isono
- Graduate School of Chemical Science and Engineering, Hokkaido University, Sapporo 060-8628, Japan
- Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Toshifumi Satoh
- Graduate School of Chemical Science and Engineering, Hokkaido University, Sapporo 060-8628, Japan
- Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Takuya Yamamoto
- Graduate School of Chemical Science and Engineering, Hokkaido University, Sapporo 060-8628, Japan
- Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Toyoji Kakuchi
- Research Center for Polymer Materials, School of Materials Science and Engineering, Changchun University of Science and Technology, Weixing Road 7989, Changchun 130012, China
| | - Shinichiro Sato
- Graduate School of Chemical Science and Engineering, Hokkaido University, Sapporo 060-8628, Japan
- Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
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2
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Gregory KP, Elliott GR, Robertson H, Kumar A, Wanless EJ, Webber GB, Craig VSJ, Andersson GG, Page AJ. Understanding specific ion effects and the Hofmeister series. Phys Chem Chem Phys 2022; 24:12682-12718. [PMID: 35543205 DOI: 10.1039/d2cp00847e] [Citation(s) in RCA: 87] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Specific ion effects (SIE), encompassing the Hofmeister Series, have been known for more than 130 years since Hofmeister and Lewith's foundational work. SIEs are ubiquitous and are observed across the medical, biological, chemical and industrial sciences. Nevertheless, no general predictive theory has yet been able to explain ion specificity across these fields; it remains impossible to predict when, how, and to what magnitude, a SIE will be observed. In part, this is due to the complexity of real systems in which ions, counterions, solvents and cosolutes all play varying roles, which give rise to anomalies and reversals in anticipated SIEs. Herein we review the historical explanations for SIE in water and the key ion properties that have been attributed to them. Systems where the Hofmeister series is perturbed or reversed are explored, as is the behaviour of ions at the liquid-vapour interface. We discuss SIEs in mixed electrolytes, nonaqueous solvents, and in highly concentrated electrolyte solutions - exciting frontiers in this field with particular relevance to biological and electrochemical applications. We conclude the perspective by summarising the challenges and opportunities facing this SIE research that highlight potential pathways towards a general predictive theory of SIE.
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Affiliation(s)
- Kasimir P Gregory
- Discipline of Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia. .,Department of Materials Physics, Research School of Physics, Australian National University, Canberra, ACT 0200, Australia
| | - Gareth R Elliott
- Discipline of Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia.
| | - Hayden Robertson
- Discipline of Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia.
| | - Anand Kumar
- Flinders Institute of Nanoscale Science and Technology, College of Science and Engineering, Flinders University, South Australia 5001, Australia
| | - Erica J Wanless
- Discipline of Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia.
| | - Grant B Webber
- School of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Vincent S J Craig
- Department of Materials Physics, Research School of Physics, Australian National University, Canberra, ACT 0200, Australia
| | - Gunther G Andersson
- Flinders Institute of Nanoscale Science and Technology, College of Science and Engineering, Flinders University, South Australia 5001, Australia
| | - Alister J Page
- Discipline of Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia.
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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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Pica A, Graziano G. A Rationalization of the Effect That TMAO, Glycine, and Betaine Exert on the Collapse of Elastin-like Polypeptides. Life (Basel) 2022; 12:life12020140. [PMID: 35207427 PMCID: PMC8876568 DOI: 10.3390/life12020140] [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: 12/24/2021] [Revised: 01/13/2022] [Accepted: 01/16/2022] [Indexed: 11/16/2022] Open
Abstract
Elastin-like polypeptides (ELPs) are soluble in water at low temperature, but, on increasing the temperature, they undergo a reversible and cooperative, coil-to-globule collapse transition. It has been shown that the addition to water of either trimethylamine N-oxide (TMAO), glycine, or betaine causes a significant decrease of T(collapse) in the case of a specific ELP. Traditional rationalizations of these phenomena do not work in the present case. We show that an alternative approach, grounded in the magnitude of the solvent-excluded volume effect and its temperature dependence (strictly linked to the translational entropy of solvent and co-solute molecules), is able to rationalize the occurrence of ELP collapse in water on raising the temperature, as well as the T(collapse) lowering caused by the addition to water of either TMAO, glycine, or betaine.
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Affiliation(s)
- Andrea Pica
- ALPX, 71 Avenue des Martyrs, 38000 Grenoble, France;
| | - Giuseppe Graziano
- Dipartimento di Scienze e Tecnologie, Università del Sannio, Via Francesco de Sanctis snc, 82100 Benevento, Italy
- Correspondence:
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6
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Yuan H, Liu G. Ionic effects on synthetic polymers: from solutions to brushes and gels. SOFT MATTER 2020; 16:4087-4104. [PMID: 32292998 DOI: 10.1039/d0sm00199f] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The ionic effects on synthetic polymers have attracted extensive attention due to the crucial role of ions in the determination of the properties of synthetic polymers. This review places the focus on specific ion effects, multivalent ion effects, and ionic hydrophilicity/hydrophobicity effects in synthetic polymer systems from solutions to brushes and gels. The specific ion effects on neutral polymers are determined by both the direct and indirect specific ion-polymer interactions, whereas the ion specificities of charged polymers are mainly dominated by the specific ion-pairing interactions. The ionic cross-linking effect exerted by the multivalent ions is widely used to tune the properties of polyelectrolytes, while the reentrant behavior of polyelectrolytes in the presence of multivalent ions still remains poorly understood. The ionic hydrophilicity/hydrophobicity effects not only can be applied to make strong polyelectrolytes thermosensitive, but also can be used to prepare polymeric nano-objects and to control the wettability of polyelectrolyte brush-modified surfaces. The not well-studied ionic hydrogen bond effects are also discussed in the last section of this review.
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Affiliation(s)
- Haiyang Yuan
- Hefei National Laboratory for Physical Sciences at the Microscale, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes, Department of Chemical Physics, University of Science and Technology of China, No. 96, Jinzhai Road, Hefei 230026, P. R. China.
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7
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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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8
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Pica A, Graziano G. Effect of sodium thiocyanate and sodium perchlorate on poly(N-isopropylacrylamide) collapse. Phys Chem Chem Phys 2019; 22:189-195. [PMID: 31799525 DOI: 10.1039/c9cp05706d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The T(collapse) of poly(N-isopropylacrylamide), PNIPAM, shows a nonlinear dependence on the concentration of NaSCN or NaClO4; in the case of NaClO4, for example, at very low concentrations of the salt, T(collapse) increases with the concentration, while it has an opposite trend at higher NaClO4 concentrations [J. Am. Chem. Soc., 2005, 127, 14505]. These puzzling experimental data can be rationalized by considering that low charge density and poorly hydrated ions, such as thiocyanate and perchlorate, interact preferentially with the surface of the polymer, and cause an increase of the magnitude of the energetic term that stabilizes swollen conformations at low salt concentrations. However, as both swollen and collapsed PNIPAM conformations are accessible to such ions in view of their large conformational freedom, the difference in the number of ions bound to PNIPAM surface upon collapse changes little on increasing the salt concentration. Thus, the energetic term that favors swollen conformations increases with salt concentration to a lesser extent than the solvent-excluded volume term (linked to the density increase caused by salt addition to water), that favors collapsed conformations, leading to a nonlinear trend of T(collapse).
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Affiliation(s)
- Andrea Pica
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, Grenoble, France
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9
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You K, Wen G, Skandalis A, Pispas S, Yang S. Anion Specificity Effects on the Interfacial Aggregation Behavior of Poly(lauryl acrylate)- block-poly( N-isopropylacrylamide). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:9904-9911. [PMID: 31282165 DOI: 10.1021/acs.langmuir.9b01561] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Aggregation behavior of an amphiphilic diblock copolymer poly(lauryl acrylate)-block-poly(N-isopropylacrylamide) (PLA-b-PNIPAM) on neutral aqueous subphases with different salt species and salt concentrations, as well as the structures of its Langmuir-Blodgett (LB) films, were systematically studied. The presence of NaCl or Na2SO4 in subphases makes PNIPAM chains shrink on the water surface and reduce their solubility underwater. On the contrary, the presence of NaNO3 or NaSCN makes PNIPAM chains more stretched on water and increase their solubility underwater, whose stretch degree and solubility both increase with the increase of salt concentration. Solubility of PNIPAM chains in the above subphase solutions is ranked as NaSCN ≫ NaNO3 > pure H2O > NaCl ≈ Na2SO4, which is almost consistent with the Hofmeister series except for the latter two close cases. All the initial LB films of PLA-b-PNIPAM exhibit tiny isolated circular micelles. Upon compression, the LB films in the case of pure H2O exhibit the dense mixed structures of circular micelles and wormlike aggregates. The formation of wormlike aggregates is due to connection of some adjoining cores, which is less possible in other subphase cases because of the conformation difference of PNIPAM chains.
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Affiliation(s)
- Kun You
- Department of Polymer Materials and Engineering, College of Material Science and Engineering , Harbin University of Science and Technology , 4 Linyuan Road , Harbin 150040 , PR China
| | - Gangyao Wen
- Department of Polymer Materials and Engineering, College of Material Science and Engineering , Harbin University of Science and Technology , 4 Linyuan Road , Harbin 150040 , PR China
| | - Athanasios Skandalis
- Theoretical and Physical Chemistry Institute , National Hellenic Research Foundation , 48 Vassileos Constantinou Avenue , Athens 11635 , Greece
| | - Stergios Pispas
- Theoretical and Physical Chemistry Institute , National Hellenic Research Foundation , 48 Vassileos Constantinou Avenue , Athens 11635 , Greece
| | - Shicheng Yang
- Department of Polymer Materials and Engineering, College of Material Science and Engineering , Harbin University of Science and Technology , 4 Linyuan Road , Harbin 150040 , PR China
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Yaghoubi Z, Parsa JB. Preparation of thermo-responsive PNIPAAm-MWCNT membranes and evaluation of its antifouling properties in dairy wastewater. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2019; 103:109779. [PMID: 31349494 DOI: 10.1016/j.msec.2019.109779] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 05/10/2019] [Accepted: 05/19/2019] [Indexed: 01/08/2023]
Abstract
A novel MWCNT-PNIPAAm nanocomposite membrane was developed with an excellent cleaning efficiency of thermo-responsive surface. The thermo-responsive N-isopropyle acryleamide (NIPAAm) monomer was polymerized on the surface of MWCNT via free radical polymerization. The prepared MWCNT-PNIPAAm nanocomposite was characterized by FTIR, SEM and TGA analyses. Various amounts of the prepared nanocomposite were incorporated into the membrane matrix by the physical blending method. The resultant membranes showed better surface wettability and pure water flux compared to pristine Polyethersulfone (PES) membrane. Furthermore, after filtration, the COD value of dairy wastewater was reduced to around 90% for all membranes. The thermo-responsive cleaning method was employed to investigate the cleaning efficiency of MWCNT-PNIPAAm membrane for dairy wastewater. The 99.9% flux recovery ratio was obtained for MWCNT-PNIPAAm-0.05% membranes. All these results confirmed that the presence of MWCNT-PNIPAAm nanocomposite in the membrane matrix improves the membrane hydrophilicity and antifouling properties.
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Affiliation(s)
- Zeynab Yaghoubi
- Department of Applied Chemistry, Faculty of Chemistry, Bu-Ali Sina University, Hamedan 65174-38683, Iran
| | - Jalal Basiri Parsa
- Department of Applied Chemistry, Faculty of Chemistry, Bu-Ali Sina University, Hamedan 65174-38683, Iran.
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11
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Pica A, Graziano G. Why does urea have a different effect on the collapse temperature of PDEAM and PNIPAM? J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.04.071] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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12
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Buchecker T, Schmid P, Grillo I, Prévost S, Drechsler M, Diat O, Pfitzner A, Bauduin P. Self-Assembly of Short Chain Poly- N-isopropylacrylamid Induced by Superchaotropic Keggin Polyoxometalates: From Globules to Sheets. J Am Chem Soc 2019; 141:6890-6899. [PMID: 30951628 DOI: 10.1021/jacs.8b12181] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We show here for the first time that short chain poly( N-isopropylacrylamide) (PNIPAM), one of the most famous thermoresponsive polymers, self-assembles in water to form (i) discrete nanometer-globules and (ii) micrometric sheets with nm-thickness upon addition of the well-known Keggin-type polyoxometalate (POM) H3PW12O40 (PW). The type of self-assembly is controlled by PW concentration: at low PW concentrations, PW adsorbs on PNIPAM chains to form globules consisting of homogeneously distributed PWs in PNIPAM droplets of several nm in size. Upon further addition of PW, a phase transition from globules to micrometric sheets is observed for PNIPAMs above a polymer critical chain length, between 18 and 44 repeating units. The thickness of the sheets is controlled by the PNIPAM chain length, here from 44 to 88 repeating units. The PNIPAM sheets are electrostatically stabilized PWs accumulated on each side of the sheets. The shortest PNIPAM chain with 18 repeating units produces PNIPAM/PW globules with 5-20 nm size but no sheets. The PW/PNIPAM self-assembly arises from a solvent mediated mechanism associated with the partial dehydration of PW and of the PNIPAM, which is related to the general propensity of POMs to adsorb on neutral hydrated surfaces. This effect, known as superchaotropy, is further highlighted by the significant increase in the lower critical solubilization temperature (LCST) of PNIPAM observed upon the addition of PW in the mM range. The influence of the POM nature on the self-assembly of PNIPAM was also investigated by using H4SiW12O40 (SiW) and H3PMo12O40 (PMo), i.e. changing the POM's charge density or polarizability in order to get deeper understanding on the role of electrostatics and polarizability in the PNIPAM self-assembly process. We show here that the superchaotropic behavior of POMs with PNIPAM polymers enables the formation and the shape control of supramolecular organic-inorganic hybrids.
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Affiliation(s)
- Thomas Buchecker
- Institute of Inorganic Chemistry, University of Regensburg , 93040 Regensburg , Germany.,ICSM, CEA, CNRS, ENSCM, Univ Montpellier , 34199 Marcoule , France
| | - Philipp Schmid
- Institute of Inorganic Chemistry, University of Regensburg , 93040 Regensburg , Germany.,ICSM, CEA, CNRS, ENSCM, Univ Montpellier , 34199 Marcoule , France
| | - Isabelle Grillo
- Institut Laue-Langevin , 6 rue Jules Horowitz , Grenoble Cedex 9 38042 , France
| | - Sylvain Prévost
- ESRF - The European Synchrotron Radiation Facility , 3800 Grenoble , France
| | - Markus Drechsler
- Laboratory of Soft Matter Electron Microscopy, University of Bayreuth , 95440 Bayreuth , Germany
| | - Olivier Diat
- ICSM, CEA, CNRS, ENSCM, Univ Montpellier , 34199 Marcoule , France
| | - Arno Pfitzner
- Institute of Inorganic Chemistry, University of Regensburg , 93040 Regensburg , Germany
| | - Pierre Bauduin
- ICSM, CEA, CNRS, ENSCM, Univ Montpellier , 34199 Marcoule , France
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Lang X, Xu EX, Wei Y, Walters LN, Hore MJ. Isomeric and structural effects in polymer cononsolvent systems. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.03.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Graziano G. On the opposite effect of guanidinium chloride and guanidinium sulphate on the kinetics of the Diels-Alder reaction. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2018.11.054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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15
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Pérez-Ramírez HA, Haro-Pérez C, Vázquez-Contreras E, Klapp J, Bautista-Carbajal G, Odriozola G. P-NIPAM in water–acetone mixtures: experiments and simulations. Phys Chem Chem Phys 2019; 21:5106-5116. [DOI: 10.1039/c8cp07549b] [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
The lower critical solution temperature (LCST) of poly-N-isopropylacrylamide (p-NIPAM) diminishes when a small volume of acetone is added to the aqueous polymer solution, and then increases for further additions, producing a minimum at a certain acetone concentration.
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Affiliation(s)
- H. A. Pérez-Ramírez
- Área de Física de Procesos Irreversibles
- División de Ciencias Básicas e Ingeniería
- Universidad Autónoma Metropolitana-Azcapotzalco
- Av. San Pablo 180
- 02200 Ciudad de México
| | - C. Haro-Pérez
- Área de Física de Procesos Irreversibles
- División de Ciencias Básicas e Ingeniería
- Universidad Autónoma Metropolitana-Azcapotzalco
- Av. San Pablo 180
- 02200 Ciudad de México
| | - E. Vázquez-Contreras
- Departamento de Ciencias Naturales
- CNI
- Universidad Autónoma Metropolitana – Cuajimalpa
- Av. Vasco de Quiroga 4871
- 05348 Ciudad de México
| | - J. Klapp
- Instituto Nacional de Investigaciones Nucleares
- ININ
- Km. 36.5, Carretera México – Toluca
- 52750 Ocoyoacac
- Mexico
| | - G. Bautista-Carbajal
- Academia de Matemáticas
- Universidad Autónoma de la Ciudad de México
- 07160 Ciudad de México
- Mexico
| | - G. Odriozola
- Área de Física de Procesos Irreversibles
- División de Ciencias Básicas e Ingeniería
- Universidad Autónoma Metropolitana-Azcapotzalco
- Av. San Pablo 180
- 02200 Ciudad de México
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16
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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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17
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Vigorita M, Cozzolino S, Oliva R, Graziano G, Del Vecchio P. Counteraction ability of TMAO toward different denaturing agents. Biopolymers 2018; 109:e23104. [DOI: 10.1002/bip.23104] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/22/2017] [Accepted: 01/16/2018] [Indexed: 01/19/2023]
Affiliation(s)
- Marilisa Vigorita
- Dipartimento di Scienze e Tecnologie; Università degli Studi del Sannio, Via Port'Arsa 11; Benevento 82100 Italy
| | - Serena Cozzolino
- Dipartimento di Scienze Chimiche; Università degli Studi di Napoli Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia; Napoli 80126 Italy
| | - Rosario Oliva
- Dipartimento di Scienze Chimiche; Università degli Studi di Napoli Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia; Napoli 80126 Italy
| | - Giuseppe Graziano
- Dipartimento di Scienze e Tecnologie; Università degli Studi del Sannio, Via Port'Arsa 11; Benevento 82100 Italy
| | - Pompea Del Vecchio
- Dipartimento di Scienze Chimiche; Università degli Studi di Napoli Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia; Napoli 80126 Italy
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18
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Pica A, Graziano G. Comment on "Relating side chain organization of PNIPAm with its conformation in aqueous methanol" by D. Mukherji, M. Wagner, M. D. Watson, S. Winzen, T. E. de Oliveira, C. M. Marques and K. Kremer, Soft Matter, 2016, 12, 7995. SOFT MATTER 2017; 13:7698-7700. [PMID: 29051960 DOI: 10.1039/c7sm01065f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In a recent article, Kremer and co-workers have combined NMR measurements and very long, all-atom MD simulations to strengthen their original claim that PNIPAM cononsolvency in water-methanol solutions is driven by the ability of MeOH molecules to bridge different monomers far away along the polymeric chain. In this comment, the results presented by Kremer and co-workers are reviewed, analyzed, and questioned regarding their ability to provide support to the bridging mechanism. Here, some pieces of evidence are provided to show that: (1) the solvent-excluded volume effect plays always a fundamental role in polymer collapse; (2) PNIPAM cononsolvency is caused by the geometric-energetic frustration experienced by the polymer when it can interact with both water and methanol molecules at the same time.
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Affiliation(s)
- Andrea Pica
- Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II Complesso Universitario di Monte Sant'Angelo, Via Cintia, 80126 Napoli, Italy
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19
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Pica A, Graziano G. Effect of heavy water on the conformational stability of globular proteins. Biopolymers 2017; 109:e23076. [PMID: 29068056 DOI: 10.1002/bip.23076] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 09/30/2017] [Accepted: 10/10/2017] [Indexed: 01/08/2023]
Abstract
It is well established from the experimental point of view that the native state of globular proteins is more stable in heavy water than in water. No robust explanation, however, has been provided up to now. The application of the theoretical approach, originally devised to rationalize the general occurrence of cold denaturation, indicates that the magnitude of the solvent-excluded volume effect is slightly smaller in heavy water than in water and cannot explain the observed protein stabilization. The latter has to be due to the strength of protein-water van der Waals attractions which are weaker in heavy water due to the smaller molecular polarizability of D2 O compared with that of H2 O molecules. Since protein-water van der Waals attractions occur more in the denatured than in the native state, this contribution leads to a stabilization of the latter through a destabilization of the former.
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Affiliation(s)
- Andrea Pica
- Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia, Napoli, 80126, Italy
| | - Giuseppe Graziano
- Dipartimento di Scienze e Tecnologie, Università del Sannio, Via Port'Arsa 11, Benevento, 82100, Italy
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20
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21
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22
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Johnson NO, Light TP, MacDonald G, Zhang Y. Anion–Caffeine Interactions Studied by 13C and 1H NMR and ATR–FTIR Spectroscopy. J Phys Chem B 2017; 121:1649-1659. [DOI: 10.1021/acs.jpcb.6b12150] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Nicolas O. Johnson
- Department of Chemistry and
Biochemistry, James Madison University, Harrisonburg, Virginia 22807, United States
| | - Taylor P. Light
- Department of Chemistry and
Biochemistry, James Madison University, Harrisonburg, Virginia 22807, United States
| | - Gina MacDonald
- Department of Chemistry and
Biochemistry, James Madison University, Harrisonburg, Virginia 22807, United States
| | - Yanjie Zhang
- Department of Chemistry and
Biochemistry, James Madison University, Harrisonburg, Virginia 22807, United States
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23
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Pica A, Graziano G. Hydrostatic pressure effect on PNIPAM cononsolvency in water-methanol solutions. Biophys Chem 2017; 231:34-38. [PMID: 28081859 DOI: 10.1016/j.bpc.2017.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 12/31/2016] [Accepted: 01/02/2017] [Indexed: 10/20/2022]
Abstract
When methanol is added to water at room temperature and 1atm, poly (N-isopropylacrylamide), PNIPAM, undergoes a coil-to-globule collapse transition. This intriguing phenomenon is called cononsolvency. Spectroscopic measurements have shown that application of high hydrostatic pressure destroys PNIPAM cononsolvency in water-methanol solutions. We have developed a theoretical approach that identifies the decrease in solvent-excluded volume effect as the driving force of PNIPAM collapse on increasing the temperature. The same approach indicates that cononsolvency, at room temperature and P=1atm, is caused by the inability of PNIPAM to make all the attractive energetic interactions that it could be engaged in, due to competition between water and methanol molecules. The present analysis suggests that high hydrostatic pressure destroys cononsolvency because the coil state becomes more compact, and the quantity measuring PNIPAM-solvent attractions increases in magnitude due to the solution density increase, and the ability of small water molecules to substitute methanol molecules on PNIPAM surface.
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Affiliation(s)
- Andrea Pica
- Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cintia, 80126 Napoli, Italy
| | - Giuseppe Graziano
- Dipartimento di Scienze e Tecnologie, Università del Sannio, Via Port'Arsa 11, 82100 Benevento, Italy.
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24
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Merlino A, Pontillo N, Graziano G. A driving force for polypeptide and protein collapse. Phys Chem Chem Phys 2017; 19:751-756. [DOI: 10.1039/c6cp07397b] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Polypeptide collapse is driven by the solvent-excluded volume decrease, the presence of nonpolar side chains is not so important.
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Affiliation(s)
- Antonello Merlino
- Dipartimento di Scienze Chimiche
- Università degli Studi di Napoli Federico II
- Complesso Universitario di Monte Sant'Angelo
- 80126 Napoli
- Italy
| | - Nicola Pontillo
- Dipartimento di Scienze Chimiche
- Università degli Studi di Napoli Federico II
- Complesso Universitario di Monte Sant'Angelo
- 80126 Napoli
- Italy
| | - Giuseppe Graziano
- Dipartimento di Scienze e Tecnologie
- Università del Sannio
- 82100 Benevento
- Italy
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25
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Liu L, Kou R, Liu G. Ion specificities of artificial macromolecules. SOFT MATTER 2016; 13:68-80. [PMID: 27906410 DOI: 10.1039/c6sm01773h] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Artificial macromolecules are well-defined synthetic polymers, with a relatively simple structure as compared to naturally occurring macromolecules. This review focuses on the ion specificities of artifical macromolecules. Ion specificities are influenced by solvent-mediated indirect ion-macromolecule interactions and also by direct ion-macromolecule interactions. In aqueous solutions, the role of water-mediated indirect ion-macromolecule interactions will be discussed. The addition of organic solvents to aqueous solutions significantly changes the ion specificities due to the formation of water-organic solvent complexes. For direct ion-macromolecule interactions, we will discuss specific ion-pairing interactions for charged macromolecules and specific ion-neutral site interactions for uncharged macromolecules. When the medium conditions change from dilute solutions to crowded environments, the ion specificities can be modified by either the volume exclusion effect, the variation of dielectric constant, or the interactions between ions, macromolecules, and crowding agents.
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Affiliation(s)
- Lvdan Liu
- Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, P. R. China 230026.
| | - Ran Kou
- Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, P. R. China 230026.
| | - Guangming Liu
- Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, P. R. China 230026.
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26
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Hatano I, Mochizuki K, Sumi T, Koga K. Hydrophobic Polymer Chain in Water That Undergoes a Coil-to-Globule Transition Near Room Temperature. J Phys Chem B 2016; 120:12127-12134. [DOI: 10.1021/acs.jpcb.6b08347] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- I. Hatano
- Research
Institute for Interdisciplinary Science and ‡Department of Chemistry, Faculty
of Science, Okayama University, Okayama 700-8530, Japan
| | - K. Mochizuki
- Research
Institute for Interdisciplinary Science and ‡Department of Chemistry, Faculty
of Science, Okayama University, Okayama 700-8530, Japan
| | - T. Sumi
- Research
Institute for Interdisciplinary Science and ‡Department of Chemistry, Faculty
of Science, Okayama University, Okayama 700-8530, Japan
| | - K. Koga
- Research
Institute for Interdisciplinary Science and ‡Department of Chemistry, Faculty
of Science, Okayama University, Okayama 700-8530, Japan
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27
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Drenscko M, Loverde SM. Characterisation of the hydrophobic collapse of polystyrene in water using free energy techniques. MOLECULAR SIMULATION 2016. [DOI: 10.1080/08927022.2016.1253840] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Mihaela Drenscko
- Department of Chemistry, College of Staten Island, City University of New York, USA
- Program in Physics, The Graduate Center of the City University of New York, USA
| | - Sharon M. Loverde
- Department of Chemistry, College of Staten Island, City University of New York, USA
- Program in Physics, The Graduate Center of the City University of New York, USA
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28
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Pica A, Graziano G. On urea's ability to stabilize the globule state of poly(N-isopropylacrylamide). Phys Chem Chem Phys 2016; 18:14426-33. [DOI: 10.1039/c5cp07507f] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Urea stabilizes the PNIPAM globule state because the increase in the solvent-excluded volume effect overwhelms the direct energetic interactions with the PNIPAM surface.
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Affiliation(s)
- Andrea Pica
- Dipartimento di Scienze Chimiche
- Università degli Studi di Napoli Federico II Complesso Universitario di Monte Sant'Angelo
- Via Cintia – 80126 Napoli
- Italy
| | - Giuseppe Graziano
- Dipartimento di Scienze e Tecnologie
- Università del Sannio
- Via Port'Arsa 11 – 82100 Benevento
- Italy
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29
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Pica A, Graziano G. An alternative explanation of the cononsolvency of poly(N-isopropylacrylamide) in water–methanol solutions. Phys Chem Chem Phys 2016; 18:25601-25608. [DOI: 10.1039/c6cp04753j] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Water/methanol competition in the interaction with PNIPAM causes a decrease in the magnitude of attractive energy, leading to cononsolvency.
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Affiliation(s)
- Andrea Pica
- Dipartimento di Scienze Chimiche
- Università degli Studi di Napoli Federico II
- Complesso Universitario di Monte Sant'Angelo
- 80126 Napoli
- Italy
| | - Giuseppe Graziano
- Dipartimento di Scienze e Tecnologie
- Università del Sannio
- 82100 Benevento
- Italy
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30
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Hayashi T, Kinoshita M. Statistical thermodynamics of aromatic–aromatic interactions in aqueous solution. Phys Chem Chem Phys 2016; 18:32406-32417. [DOI: 10.1039/c6cp06000e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
To elucidate the interactions between aromatic rings, which are believed to play essential roles in a variety of biological processes, we analyze the water-mediated interactions between toluene molecules along face-to-face stacked (FF) and point-to-face T-shaped (TS) paths using a statistical-mechanical theory of liquids combined with a molecular model for water.
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31
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Rodríguez-Ropero F, Hajari T, van der Vegt NFA. Mechanism of Polymer Collapse in Miscible Good Solvents. J Phys Chem B 2015; 119:15780-8. [PMID: 26619003 DOI: 10.1021/acs.jpcb.5b10684] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We propose a physical mechanism for co-nonsolvency of a stimulus-responsive polymer in water/methanol mixed solution based on results obtained with molecular simulations. Even though the phenomenon is well known, the mechanism behind co-nonsolvency is still under debate. Herein, we study co-nonsolvency of poly(N-isopropylacrylamide) (PNiPAM) in methanol aqueous solutions, the most widely studied and experimentally well-characterized system. Our results show that at low alcohol content of the solution methanol preferentially binds to the PNiPAM globule and drives polymer collapse. The energetics of electrostatic, hydrogen bonding, or bridging-type interactions with the globule is found to play no role. Instead, preferential methanol binding results in a significant increase in the globule's configurational entropy, stabilizing methanol-enriched globular structures over wet globular structures in neat water. This mechanism drives the reduction of the lower critical solution temperature with increasing methanol content in the co-nonsolvency regime and eventually leads to polymer collapse. The globule-to-coil re-entrance at high methanol concentrations is instead driven by changes in solvent-excluded volume of the coil and globular states imparted by a decrease in solvent density with increasing methanol content of the solution: with increasing proportion of larger solvent particles (methanol), the entropic (cavity formation) cost of redistributing solvent molecules upon polymer re-entrance becomes smaller. This effect provides a natural explanation for the experimentally observed dependence of the re-entrance transition on chain molecular weight.
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Affiliation(s)
- Francisco Rodríguez-Ropero
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie and Center of Smart Interfaces, Technische Universität Darmstadt , Alarich-Weiss-Straße 10, 64287 Darmstadt, Germany
| | - Timir Hajari
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie and Center of Smart Interfaces, Technische Universität Darmstadt , Alarich-Weiss-Straße 10, 64287 Darmstadt, Germany
| | - Nico F A van der Vegt
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie and Center of Smart Interfaces, Technische Universität Darmstadt , Alarich-Weiss-Straße 10, 64287 Darmstadt, Germany
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