Surface Modification And Polymerization Method Based On SuFEx "Click" Reaction

Since Sharpless et al.proposed the concept of "click" chemistry in 2001.The click reaction represented by Cu(?)catalyzed azide-alkyne cycloaddition(CuAAC)reaction has been widely used in organic synthesis,material preparation,and industrial production.In 2014,Sharpless et al.proposed a new type of click reaction called sulfur(?)-fluoride exchange(SuFEx)reaction with many advantages,such as high efficiency,fast speed,strong specificity,no metal catalyst,simple post-treatment,insensitive to water and oxygen,etc.Therefore,it has a broad application prospect in organic synthesis,biochemistry,material surface modification,and other research fields.In this paper,a series of simple,efficient and universal methods for constructing multifunctional surfaces and synthesizing cyclic polymers by SuFEx "click" reaction are studied.At first,BPSF,a novel diphenylketone derivative with diphenylketone and sulfonyl fluoride end-functional groups,was synthesized.The diphenylketone functional groups in BPSF can bond to the surfaces of plastics,fibers,and various surface-alkylated materials under ultraviolet irradiation.On the other hand,the sulfonyl fluoride functional groups in BPSF can achieve post-modification of the material surface through SuFEx "click" reaction.Taking PVC as the research object,the results showed that the target molecules could be immobilized on the surface quickly and effectively in one-step after five minutes of ultraviolet irradiation,which could be applied to realize the functional modification of PVC.Quantities of target functional molecules such as alkynyl,sulfhydryl,ionic liquid,reversible addition-fragmentation chain transfer polymerization(RAFT)reagent and polymers can be modified on PVC surface by this method.It provides a new approach for constructing multifunctional biomaterial surfaces rapidly and efficientlyThen,TBDMS-FSBCT,a novel trithiocarbonate RAFT reagent containing sulfonyl fluorine and silyl ether end-functional groups,was synthesized.The polymerization properties of TBDMS-FSBCT were investigated by N-isopropyl propanamide(NIPAAm)as a conjugated vinyl monomer and N-vinyl pyrrolidone(NVP)as a non-conjugated vinyl monomer.The linear polymer poly(N-isopropylamide)(L-PNIPAAm)and linear poly(N-vinyl pyrrolidone)(L-PVP)with well-defined molecular weight were successfully prepared.And the controllability of the RAFT reagent to the polymerization of both monomers was fully demonstrated by kinetic experiments.The corresponding cyclic polymers(C-PNIPAAm and C-PVP)can be easily synthesized by"clicking" cyclization of SuFEx through the sulfonyl fluorine and silyl ether end-functional groups at both ends of the obtained linear polymer chains.In this study,the linear polymer molecular could be converted into a cyclic polymer in only one step at room temperature with controllable RAFT polymerization and SuFEx "click" reaction.Moreover,it would present a good general property for both conjugated vinyl monomer and non-conjugated vinyl monomer and provide a new method to synthesize cyclic polymer efficiently.