Synthesis And Characterization Of Responsive Pseudorotaxane

Recently, increasing attention has been paid to polymer inclusion complexes (ICs) formed between various polymers and cyclodextrins (CDs) due to the great potential for biological and medical applications. This paper described the synthesis of responsive comblike polymers, and investigated the effect of solution behaviors of the polymers on their inclusion complexations with a-CD under different conditions when the polymers were in different conformations. Details are as follows:The comblike polymer, PNIPAM-b-PPEOMA-b-PNIPAM (PEOMA, Mn=950), was prepared by reversible addition-fragmentation chain transfer polymerization (RAFT) and formed inclusion complexes after selective threading of the PEO segment through the cavities of a-CD units. The polymer was characterized by1H NMR and GPC and the formed ICs were characterized by XRD,1H NMR, TGA and DSC. The effect of temperature-responsive solution behavior of PNIPAM-b-PPEOMA-b-PNIPAM on its inclusion complexation with a-cyclodextrin was studied. The results reveal that the solutions of the ICs show temperature-responsive clear/turbid transition or fluidic emulsion/gel transition depending on the concentration of the a-CD added, and the stoichiometry of EO/a-CD of the resulted ICs increase with the increasing of the temperature.The comblike polymer, P2VP-b-PPEOMA-b-P2VP, was prepared by RAFT and formed ICs after selective threading of the PEO segment through the cavities of a-CD units. The polymer was characterized by1H NMR and GPC and the formed ICs were characterized by XRD and1H NMR. The effect of pH-responsive solution behavior of P2VP-b-PPEOMA-b-P2VP on its inclusion complexation with a-CD was studied. The results reveal that the solutions of the ICs show pH-responsive clear/turbid transition or fluidic emulsion/gel transition depending on the concentration of the a-CD added, and the stoichiometry of EO/a-CD of the resulted ICs increase with the increasing of the pH.The comblike polymer PAA-b-PPEOMA was prepared by RAFT and formed pH-responsive ICs after selective threading of the PEO segment through the cavities of a-CD units. The polymer was characterized by1H NMR and GPC and the formed ICs were characterized by XRD and1H NMR. The effect of pH-responsive solution behavior of PAA-b-PPEOMA on its inclusion complexation with a-CD was studied. The results reveal that the solutions of the ICs show pH-responsive clear/turbid transition or fluidic emulsion/gel transition depending on the concentration of the a-CD added, and the stoichiometry of EO/a-CD of the resulted ICs increase with the decreasing of the pH.