We report the effect of alkyl side chain branching on melt-recrystallization of nanoconfined polypeptoid films using poly(N-octyl glycine) (PNOG) and poly(N-2-ethyl-1-hexyl glycine) (PNEHG) as model systems. Upon cooling from the isotropic melt, confined PNOG molecules recrystallize into a near-perfect orthorhombic crystal structure with the board-like molecules stacked face-to-face in the substrate-parallel direction, resulting in long-range ordered wormlike lamellae that occupy the entire film. By contrast, rod-like PNEHG molecules bearing branched N-2-ethyl-1-hexyl side chains stack into a columnar hexagonal mesophase with their backbones oriented parallel to the substrates, forming micron-sized sheaf-like superstructures under confinement, exposing large areas of empty spaces in the film. These findings highlight the effect of alkyl side chain branching on the packing motif and multiscale crystalline structure of polypeptoids under a nanoconfined geometry.

中文翻译：

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限制性多肽膜的多尺度晶体结构：烷基侧链分支的影响

我们报告了烷基侧链支化对使用聚（N-辛基甘氨酸）（PNOG）和聚（N -2-乙基-1-己基甘氨酸）（PNEHG）作为模型系统的纳米限制 polypeptoid 薄膜的熔融再结晶的影响。从各向同性熔体冷却后，受限的 PNOG 分子再结晶成近乎完美的正交晶体结构，板状分子在基板平行方向上面对面堆叠，导致长程有序的蠕虫状薄片占据整个电影。相比之下，带有支链N的棒状 PNEHG 分子-2-乙基-1-己基侧链堆叠成柱状六角形中间相，其主链平行于底物，在限制下形成微米级的束状超结构，暴露出薄膜中的大面积空白空间。这些发现突出了烷基侧链支化对纳米限制几何结构下聚肽的堆积基序和多尺度晶体结构的影响。