Micellization-induced deprotonation of thermoresponsive surfactant CAE-85 — the telechelic carboxylic group derivative of Pluronic P85

0365712 - ÚMCH 2012 RIV NL eng J - Journal Article
Šturcová, Adriana - Dybal, Jiří - Braunová, Alena - Pechar, Michal
Micellization-induced deprotonation of thermoresponsive surfactant CAE-85 — the telechelic carboxylic group derivative of Pluronic P85.
Vibrational Spectroscopy. Roč. 57, č. 2 (2011), s. 300-305. ISSN 0924-2031. E-ISSN 1873-3697
R&D Projects: GA ČR GA203/09/1478; GA ČR GA203/08/0543
Institutional research plan: CEZ:AV0Z40500505
Keywords : pluronic * ATR FTIR * deprotonation
Subject RIV: CD - Macromolecular Chemistry
Impact factor: 1.650, year: 2011

Temperature-induced micellization of CAE-85, a carboxylic acid end-standing derivative of a copolymer Pluronic P85, was studied by attenuated total reflectance Fourier-transform infrared spectroscopy and density functional theory model calculations. In polymer micelles, carboxyl end groups dissociated in a two stage process. The first stage of deprotonation appeared with the onset of micellization – in agreement with predictions of existing models and theories for ionization processes in micellar corona. In micelles well above the critical micellization temperature, the degree of CAE-85 deprotonation increased to values significantly higher compared to unimer solution. Such deprotonation correlates well with formation of hydrogen bonded carboxyl end groups due to high density of chains in the corona of developing micelles. Thus, the proton dissociation constant, pKm, specific to the micellar form exists and is different from the proton dissociation constant of solution of unimers, pKa.
Permanent Link: http://hdl.handle.net/11104/0200887