Ion Specificity Of Thermosensitive Macromolecules

In this thesis,we have investigated the amplification of ion specificity by alcohols and the application of specific ion effects in organic catalysis.The main results are as follows:(1)In the present work,we have demonstrated that Hofmeister effect can be amplified by adding alcohols to aqueous solutions.The lower critical solution temperature behavior of poly(N-isopropylacrylamide)has been employed as the model system to study the amplification of Hofmeister effect.The alcohols can more effectively amplify the Hofmeister effect following the series methanol<ethanol<1-propanol<2-propanol for the monohydric alcohols and following the series D-sorbitol ? xylitol:? meso-erythritol<glycerol<ethylene glycol<methanol for the polyhydric alcohols.Our study reveals that the relative extent of amplification of Hofmeister effect is determined by the stability of the water/alcohol complex,which is strongly dependent on the chemical structure of alcohols.The more stable solvent complex formed via stronger hydrogen bonds can more effectively differentiate the anions through the anion-solvent complex interactions,resulting in a stronger amplification of Hofmeister effect.This study provides an alternative method to tune the relative strength of Hofmeister effect besides salt concentration.(2)Surface wettability plays an important role in heterogeneous catalysis.The interaction between the catalyst and substrate can be tuned by surface wettability.Responsive P(DEA-co-ProlA)chains were grafted on silica nanoparticles via surface-initiated RAFT polymerization to prepare the smart catalyst.The interaction between PProlA and the substrate is closely related to the surface wettability.Controllable phase transition of PDEA can be used to tune the particle surface wettability,in turn controlling the interaction between the catalyst and substrate.By tuning the phase transition temperature of PDEA through ion-specific effect,the strong interaction between the catalyst and substrate can be achieved at a low temperature,which increases the efficiency and selectivity of organic catalytic reaction,accompanied by the improvement of the recycling of catalyst.