单链两亲分子的设计、合成和成膜机制

合成双分子膜的传统两亲分子设计是基于疏水尾链间相互作用的考虑.一般认为,单链两亲分子必须引入刚性片断增强疏水聚集才能形成双分子膜.因此,从两亲分子的亲水头基间相互作用的新思路出发,设计合成了一系列具有相互作用亲水头基(无刚性片断)的新单链两亲分子,其分散体系经聚集形态,凝胶/液晶相变,侧向流动性,双层结构和分子光谱等检测,提出无刚性片断的单链两亲分子,通过亲水头基间氢键、离子键、配位键等相互作用诱导疏水尾链平行聚集,使亲水与疏水作用互动加强达到平衡的成膜新机制,并利用介质体系控制膜堆积结构以调变其性能.应用新机制在水相中实现聚集形态转变的生物膜功能.新机制推广到有机相,成功地进行反双分子膜组装,形成新粘弹材料. 设计、合成的单链双头基含双刚性片断的新两亲分子、广义两亲分子等,分别在纯水、类水(乙醇)或弱极性有机溶剂中,形成不同形态、性能的有序液晶单层,表明分子组装可在任何介质中以不同驱动力进行.

Design, Synthesis of Single-Chain Amphiphiles and Membrane Formation Mechanism

The molecular design of conventional amphiphiles of synthetic bilayer membranes was based on the consideration of hydrophobic chain interaction. It was commonly considered that rigid segments were essential for single - chain amphiphiles to form stable bilayer membranes through the increase of hydrophobic assembly. This paper started with a new thought of hydrophilic headgroup interaction. A series of new single - chain amphiphiles without rigid segment were designed and synthesized. It was demonstrated that stable bilayer membranes were formed from these amphiphiles. Consequently , a new mechanism of bilayer membrane formation from these single - chain amphiphiles without rigid segment was put forward. The interactions between the hydrophilic headgroups (hydrogen bond, ionic bond, coordination bond, etc.) induced a parallel arrangement of hydrophobic chains to strengthen the hydrophilic and hydrophobic interactions to reach a balance between them. Under the guidance of the new mechanism, conventional micelle - forming single - chain amphiphiles could self - organize into bilayer membrane vesicles through the coordination of their headgroups with metal ions, which indicated a similar function of morphology transformation to biological membranes. The new mechanism was applied to organic solvent media, reverse bilayer membranes were successfully assemblied and novel elastic materials were formed. Novel bolaamphiphiles and single - chain general amphiphiles (without headgroup) with bis - rigid segments were designed and synthesized. They and the latter metal complexes and coordination polymer could self - organize into liquid - crystalline ordered monolayer membranes in pure water, ethanol, and organic solvents of low polarity, respectively , and indicate that molecular assemblies with varied functions can be prepared from well - designed novel amphiphiles in various kinds of media with different driving forces.