From Associative to Segregative Phase Separation: The Phase Behavior of Poly(acrylate)/Dodecyltrimethylammonium Complex Salts in the Presence of NaBr and NaCl

Autor(es)

Aquino Queiros, Marcos Vinicius ^[1] ; Loh, Watson ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, UNICAMP, Inst Chem, BR-13083970 Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry B; v. 125, n. 11, p. 2968-2975, MAR 25 2021.
• Citações Web of Science: 0

Resumo

We report here a systematic study on the phase behavior of dodecyltrimethylammonium-poly(acrylate) (C12TAPA) complex salts upon addition of simple salts (NaBr and NaCl). Complex salts of poly(acrylate) of two molar masses were employed (2000 and 450,000 g mol(-1)). Systems containing different surfactant mesophases were observed, whose structures were elucidated by small-angle X-ray scattering analyses. Overall, we observe a transition from associative to segregative phase separation intercalated with monophasic regions. In terms of surfactant association, a transition from micellar cubic phases to an isotropic micellar solution was observed, where these two phases occur in equilibrium with a dilute phase as a consequence of associative phase separation. However, as the salt concentration increases, segregative phase separation is observed, and scattering analyses of the surfactant-rich phase indicate the growth of micellar aggregates. These results are discussed in terms of the electrolyte effect screening the interactions between the oppositely charged surfactant and polymer and as a result of salting-out effects of the different electrolytes that prevail at higher concentrations. (AU)

• Processo FAPESP: 18/09099-3 - Comportamento de fases de complexos eletrostáticos em sistemas contendo polímeros e surfactantes na presença de sais inorgânicos
• Beneficiário: Marcos Vinícius Aquino Queirós
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 15/25406-5 - Organizando a matéria: colóides formados por associação de surfactantes, polímeros e nanopartículas
• Beneficiário: Watson Loh
• Modalidade de apoio: Auxílio à Pesquisa - Temático