Thermodynamic analysis of the conformational transition in aqueous solutions of isotactic and atactic poly(methacrylic acid) and the hydrophobic effect

Kogej, Ksenija (avtor)

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.

• Jezik: Angleški jezik
• Ključne besede: polymethacrylic acid, isotactic, conformational transition, thermodynamics, temperature dependence, hydrophobic effect, hydrophobic hydration
• Vrsta gradiva: Članek v reviji
• Tipologija: 1.01 - Izvirni znanstveni članek
• Organizacija: FKKT - Fakulteta za kemijo in kemijsko tehnologijo
• Status publikacije: Objavljeno
• Različica publikacije: Objavljena publikacija
• Leto izida: 2016
• Št. strani: 19 str.
• Številčenje: Vol. 8, iss. 5, art. 168
• PID: 20.500.12556/RUL-130304
• UDK: 544.35:544.6.018.47-036.5
• ISSN pri članku: 2073-4360
• DOI: 10.3390/polym8050168
• COBISS.SI-ID: 1536889283
• Datum objave v RUL: 13.09.2021

Gradivo je del revije

• Naslov: Polymers
• Skrajšan naslov: Polymers
• Založnik: Molecular Diversity Preservation International
• ISSN: 2073-4360
• COBISS.SI-ID: 517951257

Licence

• Licenca: CC BY 4.0, Creative Commons Priznanje avtorstva 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by/4.0/deed.sl
• Opis: To je standardna licenca Creative Commons, ki daje uporabnikom največ možnosti za nadaljnjo uporabo dela, pri čemer morajo navesti avtorja.
• Začetek licenciranja: 01.05.2016

Sekundarni jezik

• Jezik: Slovenski jezik
• Ključne besede: fizikalna kemija, vodne raztopine, polielektrolitske raztopine, polielektroliti, termodinamika, konformacijski prehodi, temperaturna odvisnost, hidrofobni efekt, hidrofobnost, polimetakrilna kislina, izotaktična polimetakrilska kislina, PMA

Projekti

• Financer: ARRS - Agencija za raziskovalno dejavnost Republike Slovenije
• Številka projekta: P1-0201
• Naslov: Fizikalna kemija