空间位阻对氢键构筑的嵌段共聚物微相分离结构的影响  

Effect of Steric Hindrance on Microphase-separated Structures of Block Copolymers Constructed by Hydrogen Bonding

作　　者：陈凯锋 刘赟 沈志豪 范星河[2] 原小涛[1] Kai-feng Chen;Yun Liu;Zhi-hao Shen;Xing-he Fan;Xiao-tao Yuan(School of Chemistry and Biological Engineering,University of Science and Technology Beijing,Beijing 100083;Beijing National Laboratory for Molecular Sciences,Key Laboratory of Polymer Chemistry and Physics of Ministry of Education,Center for Soft Matter Science and Engineering,College of Chemistry and Molecular Engineering,Peking University,Beijing 100871)

机构地区：[1]北京科技大学化学与生物工程学院,北京100083 [2]北京分子科学国家研究中心、高分子化学与物理教育部重点实验室、北京大学软物质科学与工程中心、化学与分子工程学院,北京100871

出　　处：《高分子学报》2023年第11期1681-1696,共16页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号51921002,51725301)资助项目

摘　　要：基于氢键构筑的嵌段共聚物已有广泛的研究,但关于空间位阻对这类体系微相分离结构影响的相关报道仍较少.通过选用分子量和体积分数相近的聚苯乙烯-b-聚(4-乙烯基吡啶)(PS-b-P4VP)和聚苯乙烯-b-聚(2-乙烯基吡啶)(PS-b-P2VP)2种含吡啶基团的嵌段共聚物,与合成的羧酸小分子Ben通过氢键构筑超分子型嵌段共聚物PS-b-P4VP(Ben)x和PS-b-P2VP(Ben)x,其中x为氢键给体Ben与氢键受体P4VP或P2VP的摩尔比.通过对复合比例x的调控,有效地控制了氢键复合物的微相分离结构.首先利用傅里叶红外光谱(FTIR)对复合物进行表征,确认了氢键的形成.随后利用示差扫描量热(DSC)和广角X射线散射(WAXS)技术研究了氢键复合物的相行为,发现超分子链段的玻璃化温度基本上随复合比例的增大而降低,而超分子链段P4VP(Ben)x和P2VP(Ben)x均没有液晶性.最后利用小角X射线散射(SAXS)技术对2种氢键复合物的微相分离结构进行探究,并通过绘制相图总结氢键所在位置不用导致的位阻差异对氢键复合物自组装结构的影响.这一工作为有效调控超分子型嵌段共聚物的微相分离结构提供了参考.There are plenty of studies on block copolymers constructed by hydrogen bonding in the literature.However,the number of reports on the effect of steric hindrance on the self-assembled strictures of these systems is very limited.In this work,supramolecular block copolymers PS-b-P4VP(Ben)x and PS-b-P2VP(Ben)x were constructed by hydrogen bonding between the pyridine-containing block copolymers PS-b-P4VP and PS-b-P2VP,having similar molecular weights and volume fractions and the synthesized small-molecule carboxylic acid Ben,where x is the molar ratio of the hydrogen-bonding donor Ben to the acceptor P4VP or P2VP.The microphaseseparated structures of the hydrogen-bonding complexes were effectively controlled by adjusting the value of x.Fourier transform infrared spectroscopy(FTIR)was utilized to characterize the complexes obtained,confirming the formation of hydrogen bonding.Then differential scanning calorimetry(DSC)and wide-angle X-ray scattering(WAXS)were used to investigate their phase behaviors.The glass transition temperatures of the supramolecular blocks were found to decrease with the increase of x.Neither P4VP(Ben)x nor P2VP(Ben)x exhibited liquid crystallinity.Finally,small-angle X-ray scattering(SAXS)was used to explore the microphase-separated structures of the two types of hydrogen-bonding complexes.And the effect of the steric hindrance during the formation of hydrogen bonding on the nanostructures of the hydrogen-bonding complexes was summarized by drawing the phase diagrams.This work provides the basis for effectively controlling the microphase-separated structures of supramolecular block copolymers.

关 键 词：氢键 甲壳型聚合物 嵌段共聚物 空间位阻 微相分离 

分 类 号：TQ317[化学工程—高聚物工业]