Thermodynamics of the multi-stage self-assembly of pH-sensitive gradient copolymers in aqueous solutions

Černochová, Zulfiya; Bogomolova, Anna; Borisova, O. V.; Filippov, Sergey K.; Černoch, Peter; Billon, L.; Borisov, O. V.; Štěpánek, Petr

doi:https://dx.doi.org/10.1039/C6SM01105E

Number of the records: 1

Thermodynamics of the multi-stage self-assembly of pH-sensitive gradient copolymers in aqueous solutions

1.

SYSNO ASEP	0461607
Document Type	J - Journal Article
R&D Document Type	Journal Article
Subsidiary J	Článek ve WOS
Title	Thermodynamics of the multi-stage self-assembly of pH-sensitive gradient copolymers in aqueous solutions
Author(s)	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, ORCID}
Source Title	Soft Matter - ISSN 1744-683X Roč. 12, č. 32 (2016), s. 6788-6798
Number of pages	11 s.
Language	eng - English
Country	GB - United Kingdom
Keywords	gradient copolymers ; isothermal titration calorimetry
Subject RIV	CF - Physical ; Theoretical Chemistry
R&D Projects	LH14079 GA MŠMT - Ministry of Education, Youth and Sports (MEYS)
	GC15-10527J GA ČR - Czech Science Foundation (CSF)
Institutional support	UMCH-V - RVO:61389013
UT WOS	000382112600009
EID SCOPUS	84982133338
DOI	10.1039/C6SM01105E
Annotation	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.
Workplace	Institute of Macromolecular Chemistry
Contact	Eva Čechová, cechova@imc.cas.cz ; Tel.: 296 809 358
Year of Publishing	2017

Number of the records: 1