Synthesis And Micellization Of Amphiphilic Polycaprolactone-b-Polycaprolactone Block Copolymer

Amphihilic biodegradable diblock polycaprolactone-b-polycaprolactone (PCL-6-PEEP) copolymers were synthesized by ring-opening polymerization of phosphatewith hydroxyl-terminated polycaprolactone(PCL-OH) as a macroinitiatorl,which wassynthesized by ring-opening polymerization of caprolactone initiated by dodecanolusing stannous octoate as catalyst. The structure of the copolymer was confirmed byFT-IR,’H-NMR, GPC. The effects of feed ratio on copolymers molecular weight andPDI were investigated. The polymer micelles was prepared by evaporation methodand The fluorescence technique was used to determine the critical micelleconcentrations (CMC) of copolymer micelles solution. DLS was used to determine ofparticle size distirbution.The results indicated that in water the PCL-A-PEEP synthesized canself-assembled into nanoscale micelles with hydrophilic shell and hydrophobic core.The CMC increased with the growth of the hydrophilic segments. However，the sizeof the micelles decreases with increase of the hydrophilic chain. The LCST decreasedas the solution of the PH decreases. Therefore, by changing the length of thehydrophilic chain can change the size of the micelles size，the LCST of the micellescan also be controlled through the PH of the solution.