Conformational transition of Poly (vinylbenzyltrimethylammonium chloride) (PVBTMAC) brush in the presence of Hofmeister anions

Abstract This study pertains to the conformational changes of Poly (vinylbenzyltrimethylammonium chloride) (PVBTMAC) brush onto $ SiO_{2} $-coated resonator; which was further incorporated by using quartz crystal microbalance with dissipation (QCM-D) in the presence of Hofmeister series of anions as...
Ausführliche Beschreibung

Abstract This study pertains to the conformational changes of Poly (vinylbenzyltrimethylammonium chloride) (PVBTMAC) brush onto $ SiO_{2} $-coated resonator; which was further incorporated by using quartz crystal microbalance with dissipation (QCM-D) in the presence of Hofmeister series of anions as a function of ionic strength. Gradual shrinkage of highly extended PVBTMAC followed by loose inhomogeneous layer was on account of change in frequency (∆f) and dissipation (ΔD) at low ionic strength. On the contrary, the increase in ionic strength collapses chains and dense homogenous layer is formed. The chaotropic anions comparativley bring drastic change in frequency unlike kosmotropic anions. This is because weakly hydrated chaotropic anions form strong ion pair with weakly hydrated trimethyl ammonium group on the PVBTMAC brush and as a result strong counter ion condensation was observed on polymer chain. Thus, the apparent mass associated with PVBTMAC chains increases that accounts for large change in ∆f. Ausführliche Beschreibung