Study On The Multiscale Regulation Of Sequence Structure For Functionalized Polymer

With the wide applications of polymer materials,the demand for the development of high performance materials is also increasing.While the properties of the polymers are closely related to their structures,the functionalization and topology of polymer have significant effect on improving polymer properties.So,the precise synthesis of functionalized polymer with well-defined sequence structure can provide precise templates for polymer topology,endow polymer with rich properties,and offer theoretical basis for the research of the relationship of“structure-property”.Thus how to effectively regulate the sequence structure in synthetic polymer has become one of the emerging and challenging core in polymer chemistry.At present,the methods of sequence control are relatively simple,however,there are few researches of how to realize the multiscale regulation of sequence structure in synthetic polymer.In this paper,DPE derivatives with different substituents were synthesized,three sequence-defined polymers were designed and prepared based on living anionic polymerization,and the multiscale regulation of monomer sequence and periodicity in polymer chains was successfully achieved.Additionally,an efficient and convenient methodology for the synthesis of periodic-controlled sequence-defined bottlebrush polymers was developed via hydrosilylation.1.Based on the strategy for sequence regulation with living anionic polymerization,and combination of many kinds of polymerization reactions,three sequence-defined polymers with similar number of SiH functional groups per chain but totally different periodicities which distributed as gradient,tandem and symmetrical structures were synthesized,and the monomer sequence distributions in these three polymers were confirmed by in situ ~1H NMR.Through different feeding methods and coupling reaction after polymerization during the living anionic copolymerization of Dimethyl-[4-(1-phenylvinyl)phenyl]silane(DPE-SiH)and Styrene(St),the multiscale regulation of monomer sequence and functionalized block periodicity in polymer chains was successfully achieved.2.Then,these gradient,tandem and symmetrical polymers were applied as backbones for the synthesis of corresponding bottlebrush polymers.The polymeric branches(the chain-end alkynyl functionalized polystyrenes,PS-yne)were conveniently and efficiently grafted onto the backbones via hydrosilylation,with all conversions above 97%.The basic solution and thermal properties of the bottlebrush polymers and their corresponding backbones were investigated,and the results indicated that the different sequence structures and block periodicities of the polymers display remarkable influences.