Effect of cyclodextrins on pH-induced conformational transition of poly(methacrylic acid)

0364990 - ÚMCH 2012 RIV SK eng J - Journal Article
Horský, Jiří - Podešva, Jiří - Walterová, Zuzana
Effect of cyclodextrins on pH-induced conformational transition of poly(methacrylic acid).
Chemical Papers. Roč. 65, č. 6 (2011), s. 847-854. ISSN 0366-6352
R&D Projects: GA ČR GA202/09/2078
Institutional research plan: CEZ:AV0Z40500505
Keywords : cyclodextrins * inclusion complexes * polyelectrolytes
Subject RIV: BO - Biophysics
Impact factor: 1.096, year: 2011

A pH-induced conformational transition (CT) of atactic poly(methacrylic acid) (PMMA) from the contracted to expanded conformation was investigated by viscometry, potentiometric titration, and anthracene solubilisation in the presence of - glucose, α-cyclodextrin (αCD), and γ-cyclodextrin (γCD), respectively. No effect of glucose and αCD on CT was observed. On the other hand, the CT characteristic features were absent in the presence of γCD. The different effects of the co-solutes indicate that the interaction between PMAA and γCD corresponds to the partial inclusion of the PMAA chain into the γCD cavity. The viscometry and anthracene solubilisation imply that γCD promotes the expanded conformation of PMAA at low pH. The potentiometric behaviour corresponds to that of the contracted PMMA conformation. Thus the results suggest the hierarchical picture of the PMAA conformation at low pH in which the local arrangement of the PMAA chain is a prerequisite for clustering on a larger scale.
Permanent Link: http://hdl.handle.net/11104/0006573