The Synthesis Of Diblock Copolymers And Self-assembly

The self-assembly of block copolymer is one of the most extensiveand in-depth the areas in macromolecular self-assembly. It has greatapplication value in the field of drug delivery, gene transfection andcatalysis. How to control block copolymer self-assembly effectively is ahot and difficult of study. The linear and linear-dendritic block copolymerswas designed and synthesized in this article. And used α-cyclodextrin（α-CD） and temperature to control the self-assembly of block copolymers.The main contents are illustrated as follow:1. Polycaprolactone-b-Poly （N-isopropyl acrylamide）（PCL-b-PNIPAM） block copolymer was synthesized by cationicring-opening polymerization （ROP） and reversible addition andfragmentation chain transfer polymerization （RAFT）. The（Pseudo）-polyrotaxane structure Compounds α-CD-PCL-b-PNIPAM wasgot by containing and complexation. The structure of products werecharacterized and analysised by patterns of¹H NMR, FTIR and GPC. Thethermal performance of products were characterized by TGA and DSC. Theresults showed that the thermal stability of PCL chain segments was improved significantly because of the α-CD nested on the PCL.2. The micellar morphology of PCL-b-of PNIPAM can be tuned bytemperature and the main competition of object. The PNIPAM has atemperature responsive. The PNIAPM changed hydrophilic to hydrophobicwhen the temperature greater than32°C. And the size of micellar reducedrapidly because of the shell shrinked and collapsed. The α-CD-PCL-b-ofPNIPAM can not form micelles in water because the α-CD-PCL inclusioncomplexes （ICs） were hydrophilic. The Binding of α-CD and phenolstronger than α-CD and PCL, so phenol can scramble down α-CD fromPCL, and the micelles can be re-formation. The results were obtained byTEM and DLS characterization.3. The linear-dendritic polymer PCL-T₁-Q₁-T₂-Q₂-T₃-Q₃-Dsynthesized by click chemistry. The structure of products was confirmed byIR,¹H NMR and GPC characterization. The linear chain of polymer is PCL.And the outside of dendritic has8carboxyls. Therefore, this polymer haspotential applications in drug delivery and catalytic.