Thermodynamic Analysis of the Conformational Transition in Aqueous Solutions of Isotactic and Atactic Poly(Methacrylic Acid) and the Hydrophobic Effect
| Autor: | Ksenija Kogej |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
polymethacrylic acid
Poly(methacrylic acid) Polymers and Plastics Enthalpy polimetakrilna kislina 02 engineering and technology 010402 general chemistry 01 natural sciences Heat capacity Article temperaturna odvisnost Hydrophobic effect lcsh:QD241-441 chemistry.chemical_compound thermodynamics lcsh:Organic chemistry Organic chemistry termodinamika temperature dependence polielektrolitske raztopine PMA konformacijski prehodi Aqueous solution conformational transition isotactic hidrofobni efekt General Chemistry polielektroliti 021001 nanoscience & nanotechnology 0104 chemical sciences Crystallography hidrofobnost Methacrylic acid chemistry izotaktična polimetakrilska kislina hydrophobic hydration udc:544.35:544.6.018.47-036.5 Protein folding hydrophobic effect 0210 nano-technology Entropy (order and disorder) fizikalna kemija vodne raztopine |
| Zdroj: | Polymers; Volume 8; Issue 5; Pages: 168 Polymers, Vol 8, Iss 5, p 168 (2016) Polymers Polymers, vol. 8, no. 5, 168, 2016. |
| ISSN: | 2073-4360 |
| DOI: | 10.3390/polym8050168 |
| Popis: | The affinity of amphiphilic compounds for water is important in various processes, e.g., in conformational transitions of biopolymers, protein folding/unfolding, partitioning of drugs in the living systems, and many others. Herein, we study the conformational transition of two isomer forms of poly(methacrylic acid) (PMA), isotactic (iPMA) and atactic (aPMA), in water. These isomers are chemically equivalent and differ only in the arrangement of functional groups along the chain. A complete thermodynamic analysis of the transition of the PMA chains from the compact to the extended form (comprising the conformational transition) in water in the presence of three alkali chlorides is conducted by determining the free energy, enthalpy, and entropy changes of the process as a function of temperature, and therefrom also the heat capacity change. The heat capacity change of the transition is positive (+20 J/K mol) for aPMA and negative (-50 J/K mol) for iPMA. This result suggests a different affinity of PMA isomers for water. The conformational transition of iPMA is parallel to the transfer of polar solutes into water, whereas that of aPMA agrees with the transfer of nonpolar solutes into water. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|