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Thermodynamics of the multi-stage self-assembly of pH-sensitive gradient copolymers in aqueous solutions
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SYSNO ASEP 0461607 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název Thermodynamics of the multi-stage self-assembly of pH-sensitive gradient copolymers in aqueous solutions Tvůrce(i) Černochová, Zulfiya (UMCH-V) RID, ORCID
Bogomolova, Anna (UMCH-V) RID
Borisova, O. V. (FR)
Filippov, Sergey K. (UMCH-V) RID, ORCID, SAI
Černoch, Peter (UMCH-V) RID, ORCID
Billon, L. (FR)
Borisov, O. V. (FR)
Štěpánek, Petr (UMCH-V) RID, ORCIDZdroj.dok. Soft Matter - ISSN 1744-683X
Roč. 12, č. 32 (2016), s. 6788-6798Poč.str. 11 s. Jazyk dok. eng - angličtina Země vyd. GB - Velká Británie Klíč. slova gradient copolymers ; isothermal titration calorimetry Vědní obor RIV CF - Fyzikální chemie a teoretická chemie CEP LH14079 GA MŠMT - Ministerstvo školství, mládeže a tělovýchovy GC15-10527J GA ČR - Grantová agentura ČR Institucionální podpora UMCH-V - RVO:61389013 UT WOS 000382112600009 EID SCOPUS 84982133338 DOI 10.1039/C6SM01105E Anotace The self-assembly thermodynamics of pH-sensitive di-block and tri-block gradient copolymers of acrylic acid and styrene was studied for the first time using isothermal titration calorimetry (ITC) and dynamic light scattering (DLS) performed at varying pH. We were able to monitor each step of micellization as a function of decreasing pH. The growth of micelles is a multi-stage process that is pH dependent with several exothermic and endothermic components. The first step of protonation of the acrylic acid monomer units was accompanied mainly by conformational changes and the beginning of self-assembly. In the second stage of self-assembly, the micelles become larger and the number of micelles becomes smaller. While solution acidity increases, the isothermal calorimetry data show a broad deep minimum corresponding to an exothermic process attributed to an increase in the size of hydrophobic domains and an increase in the structure's hydrophobicity. The minor change in heat capacity (Delta C-p) confirms the structural changes during this exothermic process. The exothermic process terminates deionization of acrylic acid. The pH-dependence of the zeta-potential of the block gradient copolymer micelles exhibits a plateau in the regime corresponding to the pH-controlled variation of the micellar dimensions. The onset of micelle formation and the solubility of the gradient copolymers were found to be dependent on the length of the gradient block. Pracoviště Ústav makromolekulární chemie Kontakt Eva Čechová, cechova@imc.cas.cz ; Tel.: 296 809 358 Rok sběru 2017
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