文献类型：期刊文献

英文题名：Synthesis of high-χ PTFEMA-b-P2VP block copolymers and perpendicular lamellar orientation control via neutral underlayer design

作者：Wu, Wanqing[1];Zhang, Zhipeng[1];Shen, Xinping[2];Liu, Xianhe[2];Li, Xinxin[1]

机构：[1]East China Univ Sci & Technol, Sch Mat Sci & Engn, Key Lab Specially Funct Polymer Mat & Related Tech, Minist Educ, Shanghai 200237, Peoples R China;[2]Fudan Univ, Sch Microelect, Shanghai 200433, Peoples R China

年份：2026

卷号：360

外文期刊名：POLYMER

收录：;EI(收录号：20262520928926);WOS:【SCI-EXPANDED(收录号:WOS:001803659100001)】；

基金：The authors are grateful for the financial support provided by the Fundamental Research Funds for the Central Universities (Grant No. JKD01221701) and from the National Science Foundation of China (No. 62404054) . Part of the experimental work has been carried out in Fudan Nanofabrication Laboratory.

语种：英文

外文关键词：High chi block copolymer; Neutral underlayer; Vertical orientation control

摘要：Controlling molecular architecture and interfacial interactions is critical for realizing well-defined microphase-separated structures in block copolymer systems. Here, we investigate poly(2,2,2-trifluoroethyl methacrylate)-block-poly(2-vinylpyridine) (PTFEMA-b-P2VP) as a high-chi platform enabled by strong repulsive interactions between fluorinated and polar blocks. A series of low-degree-of-polymerization PTFEMA-b-P2VP diblock copolymers was synthesized via reversible addition-fragmentation chain-transfer (RAFT) polymerization. Molecular dynamics simulations indicate a high Flory-Huggins interaction parameter (chi approximate to 0.3 at 150 degrees C), leading to rapid microphase separation into ordered lamellar morphologies within 15 min at 100 degrees C. Small-angle X-ray scattering measurements reveal lamellar spacings of 17.9 - 32.7 nm, corresponding to feature sizes down to approximately 9 nm, demonstrating the suitability of this system for sub-10 nm directed self-assembly (DSA). Despite the strong segregation strength, the large surface-energy contrast between the two blocks induces a pronounced preference for parallel lamellar orientation at solid interfaces, which limits perpendicular alignment. To address this interfacial constraint, we introduce a matched neutral underlayer strategy using random copolymer brushes chemically analogous to the constituent blocks of PTFEMA-b-P2VP, incorporating glycidyl methacrylate (GMA) as a cross-linkable third monomer. These underlayers effectively balance interfacial interactions, enabling robust perpendicular lamellar orientation during solvent-thermal annealing. Furthermore, combining the neutral underlayers with grapho-epitaxial templates enables directed self-assembly of well-ordered line patterns with linewidths of similar to 10-12 nm. This work thus establishes a practical and materials-efficient route for achieving perpendicular lamellar orientation in fluorinated block copolymers and other high-chi systems, providing a general and transferable strategy for DSA and related nanofabrication technologies that demand precise nanoscale morphology control.