Preparation of Thermosensitive Hollow Imprinted Microspheres via Combining Distillation Precipitation Polymerization and Thiol-ene Click Chemistry

Hollow molecular imprinted polymer microspheres were prepared by distillation precipitation polymerization with(S)-(+)-ibuprofen(S-IBF)as template molecule and acrylamide(AM)as functional monomer.Using the silicon dioxide(SiO_(2),180 nm)modified by 3-(trimethoxysilyl)propyl methacrylate(MPS)as the template micro-spheres,the molecular imprinted shells were coated on successfully(SiO_(2)@MIPs).The thermosensitive SiO_(2)@MIPs-PNIPAM core-shell microspheres were subsequently prepared by grafting the PNIPAM chains(M_(n)=1.21×10^(4)g/mol,polydispersity index=1.30),which were prepared by reversible addition-fragmentation chain transfer(RAFT)polymerization,on the surface of SiO_(2)@MIPs microspheres via the thiol-ene click chemistry.The grafting density of PNIPAM brushes on the SiO_(2)@MIPs microspheres was about 0.18 chains/nm^(2).After HF etching,the hollow imprinted microspheres were finally obtained.For thermosensitivity analysis,the phase transition temperatures of multifunctional nanoparticles were measured by DSL at 25℃and 45℃respectively,and the sizes of the microspheres changed by about 35 nm.The modified microspheres presented excellent controlled release property to S-IBF,moreover about half amount of the adsorptions passed into acetonitrile-water solution through the specific holes of imprinted shell at 25℃under vibration.