Intermolecular interaction of supramolecular organic–inorganic hybrid composites of sulfonated polystyrene and oligomeric silsesquioxane possessing pyridyl groups

Supramolecular organic–inorganic hybrid composites of pyridyl groups-possessing oligomeric silsesquioxane (PyOSS) synthesized by the reaction of 2-(2-pyridylethyl)trimethoxysilane and trimethoxyphenylsilane in the molar ratio of 3/5 with 1,3-propanedisulfonic acid (PDS), 1,5-naphthalenedisulfonic acid (NDS), and poly(4-styrenesulfonic acid) (PSS) were prepared by solution casting method at SO3H/pyridine 1/1. From the FT-IR analysis, the formation of pyridinium cation moiety was confirmed for PDS/PyOSS and NDS/PyOSS, while it could not be elucidated for PSS/PyOSS. As a result of XPS analysis of the newly prepared hybrid composites of PyOSS and sulfonated polystyrenes (SPSx’s) with different degrees of sulfonation (x = 3, 8, 23%), the formation of pyridinium ion structure was confirmed for SPS23/PyOSS, and the ionic interaction gradually changed to hydrogen-bonding interaction with decreasing degree of sulfonation of SPSx. Although the glass transition temperature of SPSx moiety was little affected by the addition of PyOSS, the glass transition itself was gradually weaken and was not detected for SPS23/PyOSS.