文献类型：期刊文献

英文题名：Evolution of Curvatures Between Lamellar and Bicontinuous Phases: Formation of Saddle-Shaped Hierarchical Lamellar Structures in Binary Self-Assembly System

作者：Wang, Shuqi[1];Li, Ya[1];Yang, Bin[1];Chen, Hao[2];Han, Lu[3];Cao, Yuanyuan[1];Li, Yongsheng[1]

机构：[1]East China Univ Sci & Technol, Frontiers Sci Ctr Materiobiol & Dynam Chem, Shanghai Engn Res Ctr Hierarch Nanomat, Sch Mat Sci & Engn,Key Lab Ultrafine Mat,Minist Ed, Shanghai 200237, Peoples R China;[2]ShanghaiTech Univ, Inst Math Sci, 393 Middle Huaxia Rd, Shanghai 201210, Peoples R China;[3]Tongji Univ, Sch Chem Sci & Engn, 1239 Siping Rd, Shanghai 200092, Peoples R China

年份：2026

卷号：22

期号：7

外文期刊名：SMALL

收录：;EI(收录号：20255119758531);WOS:【SCI-EXPANDED(收录号:WOS:001640743100001)】；

基金：The authors thank Prof. Hexiang Deng and Dr. Gaoli Hu (Wuhan University) for the support for SAXS measurements, and Dr. Xueliang Zhang (Tongji University) for the help in ET reconstruction. This work was financially supported by the National Key Research and Development Program of China (2022YFC2403200), the National Natural Science Foundation of China (22472058 and 22425303), Shanghai Pilot Program for Basic Research (22TQ1400100-13), the Fundamental Research Funds for the Central Universities.

语种：英文

外文关键词：bicontinuous cubic phase; Gaussian curvature; lamellar phase; mean curvature; structural transition

摘要：Curvatures are fundamental parameters governing the topological changes and phase separations in soft matter systems. Explorations of Gaussian curvature, mean curvature, and their combination (as interfacial curvature linked to packing parameter) are essential for understanding the dynamic self-assembly processes, especially for the critical and classic lamellar-to-bicontinuous transition. However, whether intermediate states arising from the changes in these curvatures exist remains a long-standing controversy. Herein, this issue is addressed by identifying a unique saddle-shaped hierarchical lamellar phase in a binary self-assembly system containing polystyrene-b-poly(acrylic acid) (PS-b-PAA) and stearyltrimethylammonium bromide (STAB). This intermediate phase exhibits characteristics with negative Gaussian curvature similar to bicontinuous phase while maintaining lamellar topologies. Its existence attributes to the competing effects of the inserted STAB micelles imposed on PAA segments: electrostatic screening reduces PAA effective volume, while volume expansion increases it. This competition balance promotes the lamellae toward saddle-shapes with enhanced molecular capacity and modulates their interfacial curvature to a critical intermediate value that is rarely stable in block copolymer systems. The thermostability of this intermediate phase serves as compelling evidence for the smooth interfacial curvature evolution pathway. This discovery provides insights into phase transformations in biological membranes, marking a significant advance in understanding complex soft matter systems.