摘要
宏观超分子组装的研究对象是表面修饰有大量超分子识别基团的10μm以上的宏观构筑基元,以及它们之间基于超分子多重相互作用的碰撞、识别和组装的过程,它是超分子化学的新兴研究方向,为体相超分子材料的制备提供了新的思路.宏观构筑基元的表面柔顺性是决定构筑基元间能否通过多重相互作用,增强相互作用,实现组装的关键要素之一.本文从界面间相互作用出发,通过交替层状自组装方法,在刚性聚二甲基硅氧烷(PDMS)构筑基元表面分别构筑不同层数的聚电解质多层膜,以调控宏观构筑基元的表面柔顺性,并研究聚电解质多层膜层数对于宏观构筑基元组装行为的影响.通过研究在水中叠加组装的时间与聚电解质多层膜层数的关系,我们发现当构筑基元表面修饰的聚电解质多层膜层数较少时,经过长时间叠加也不能发生组装;随着构筑基元表面修饰的聚电解质多层膜层数的增加,可以在较短的时间内叠加实现组装.同时对构筑基元之间的相互作用力随时间的变化进行了原位测量,其力值与上述组装行为一致.本工作验证了"具有高柔性表面是宏观超分子组装的设计原则",说明通过调控构筑基元表面柔顺性可以调控其宏观组装行为.
Macroscopic supramolecular assembly (MSA)is a recent progress in supramolecular chemistry to associate large building blocks with a size larger than 10μm through non-covalent interactions,which provides new ideas and solutions to the fabrication of supramolecular bulk materials.However,with increasing the size of the building blocks,it is difficult to achieve MSA because of insufficient binding strength between macroscopic building blocks.According to previous reports,the key element to achieve MSA is the high surface-flexibility,which endows the supramolecular groups on the surface with high freedom to reach interactive distance and interacts with each other through multivalent effect,thus enhancing the apparent binding constant of the macroscopic building blocks.Herein,we synthesized the grafted supramo- lecular polyelectrolytes which contained the host and guest functional groups as PAA-CD and PAA-Azo,respectively. Through modifying the polydimethylsiloxane (PDMS)building blocks with different number of polyelectrolyte multilayers contained β-cyclodextrin (CD)/azobenzene (Azo)groups by layer-by-layer method,we adjusted the surface-flexibility of the building blocks and systematically investigated the assembly behaviors of building blocks with varied number of polyelectrolyte multilayers.The results represent the building blocks modified with CD/Azo groups respectively cannot achieve MSA even stacking in water for long time (600min)when the number of multilayers on the surface is few (5 bilayers);with increasing number of polyelectrolyte multilayers,the time for realizing MSA exhibits a decreasing trend. In addition,the interactive forces between PDMS building blocks with different number of multilayers were in situ measured in water with a DCAT apparatus.The interactive force between building blocks modified with CD/Azo groups gradually increase with the increased interaction time,and the growing rate of the forces is larger as the number of multilayers increases.The in-situ force measurement result correspo
作者
刘崇现
张倩
张亚军
成梦娇
石峰
Chongxian Liu;Qian Zhang;Yajun Zhang;Mengjiao Cheng;Feng Shi(State Key Laboratory of Organic-Inorganic Composite,Beijing Laboratory of Biomedical Materials,Beijing University of Chemical Technology,Beijing 100029,China)
出处
《科学通报》
EI
CAS
CSCD
北大核心
2018年第34期3650-3657,共8页
Chinese Science Bulletin
基金
国家自然科学基金(21604002)资助.
关键词
宏观超分子组装
聚电解质多层膜
表面柔顺性
主客体超分子作用
macroscopic supramolecular assembly
polyelectrolyte multilayers
surface-flexibility
host-guest recognition
