Smectic polymer vesicles

Abstract

Graphical AbstractEllipsoidal smectic polymer vesicles were formed from amphiphilic block copolymers in which the hydrophobic block is a smectic liquid crystal polymer.2 SummaryPolymer vesicles are stable robust vesicles made from block copolymer amphiphiles. Recent progress in the chemical design of block copolymers opens up the exciting possibility of creating a wide variety of polymer vesicles with varying fine structure, functionality and geometry. Polymer vesicles not only constitute useful systems for drug delivery and micro/nano-reactors but also provide an invaluable arena for exploring the ordering of matter on curved surfaces embedded in three dimensions. By choosing suitable liquid-crystalline polymers for one of the copolymer components one can create vesicles with smectic stripes. Smectic order on shapes of spherical topology inevitably possesses topological defects (disclinations) that are themselves distinguished regions for potential chemical functionalization and nucleators of vesicle budding. Here we report on glassy striped polymer vesicles formed from amphiphilic block copolymers in which the hydrophobic block is a smectic liquid crystal polymer containing cholesteryl-based mesogens. The vesicles exhibit two-dimensional smectic order and are ellipsoidal in shape with defects, or possible additional budding into isotropic vesicles, at the poles.

Stimuli-Responsive Polymersomes

“…Rigid rods and tubules instead of fluid cylindrical micelles and planar bilayers are, for example, obtained in these kinds of small amphiphilic molecules. In the case of coil-rod block copolymers, the shape anisotropy and additional order (introduced by liquid crystalline, crystalline structures and secondary peptide structures such as a helices or b sheets) in the rod-like block also influences considerably the self-assembly (Pinol et al 2007;Jia et al 2009;Jenekhe and Chen 1998;Massey et al 2000;Kukula et al 2002;Bellomo et al 2004;Burkoth et al 2000;Jiang et al 2007a). In conclusion, the polymersome formation depends on the chemical and physical structure of the block copolymers.…”

Synthesis of Terpene-Based Polymers

“…What has been of great interest is how the LC nature of the hydrophobic block affects the self-assembly in aqueous solution. Ellipsoidal vesicles are formed by PEG-block-poly(cholesteryl acryloyloxyethyl carbonate) and found to exhibit 2D smectic order [196]. Long nanofibers are formed by poly(N,N-diethylacrylamide)-block-poly(cholesteryl methacryloyloxyethyl carbonate), while the block copolymer with a polystyrene hydrophobic block and the same hydrophobic content forms vesicles in solution [198].…”

“…Living/controlled radical polymerizations have been employed recently for Chol-based vinyl monomers, including ATRP [195][196][197] and reversible additionfragmentation chain transfer (RAFT) [198,199], which allowed the preparation of well-defined diblock copolymers (low PDI) with one block being totally synthetic (hydrophilic) and the other block being the Chol-pending conjugate (hydrophobic). What has been of great interest is how the LC nature of the hydrophobic block affects the self-assembly in aqueous solution.…”

Preparation of New Amphiphilic Liquid-Crystal Diblock Copolymers Bearing Side-on Cholesteryl Mesogen and Their Self-aggregation

“…因此, 设计采用具有胆 固醇液晶元的疏水单元, 通过可控共聚合, 制备新型两 亲性液晶嵌段功能大分子, 将为发展具有外部刺激响应 性的生物功能材料提供新的可能. 围绕含有胆固醇液晶元的两亲嵌段液晶功能大分 子的制备与自聚集行为研究, 本组与居里研究所李敏慧 小组前期的合作研究中, 发现以系列分子量甲基封端聚 乙二醇(MPEG)为亲水嵌段构建的两亲胆固醇液晶嵌段 功能大分子在选择性溶剂中自组装形成具有多级结构 的纳米纤维、囊泡、中空纳米管等, 刚性胆固醇液晶元 有序堆砌与预组装诱导嵌段功能大分子的本体和溶液 自组织聚集行为 [11,12] . 为了进一步拓展该系列胆固醇液 晶嵌段大分子的生物材料应用, 本组最近报道了具有自 由羟基的聚甲基丙烯酸羟乙酯(PHEMA)为亲水性嵌段 两亲胆固醇液晶嵌段功能大分子, 有趣地发现液晶嵌段 的相转变温度(T LC-I )高于胆固醇液晶均聚物, 揭示亲水 嵌段氢键网络的存在, 可能在嵌段共聚物微相分离的过 程中诱导液晶的有序取向与排列 [13] .…”