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 microspheres, 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°C and 45°C 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°C under vibration.