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

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389013%3A_____%2F16%3A00461607" target="_blank" >RIV/61389013:_____/16:00461607 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1039/C6SM01105E" target="_blank" >http://dx.doi.org/10.1039/C6SM01105E</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/C6SM01105E" target="_blank" >10.1039/C6SM01105E</a>

Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

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 (ΔCp) confirms the structural changes during this exothermic process. The exothermic process terminates deionization of acrylic acid. The pH-dependence of the ζ-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.

Název v anglickém jazyce

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

Popis výsledku anglicky

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 (ΔCp) confirms the structural changes during this exothermic process. The exothermic process terminates deionization of acrylic acid. The pH-dependence of the ζ-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.

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

CF - Fyzikální chemie a teoretická chemie

OECD FORD obor

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Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Soft Matter

ISSN

1744-683X

e-ISSN

—

Svazek periodika

12

Číslo periodika v rámci svazku

32

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

11

Strana od-do

6788-6798

Kód UT WoS článku

000382112600009

EID výsledku v databázi Scopus

2-s2.0-84982133338