We demonstrated the synthesis and directed self-assembly (DSA) of poly(styrene-b-(lactic acid-alt-glycolic acid)) (PS-b-PLGA). Lamellae-forming PS-b-PLGAs with a range of molecular weights were synthesized by ring-opening polymerization (ROP) of LGA (d,l-3-methyl-1,4-dioxane-2,5-dione) from hydroxy-terminated polystyrene (PS–OH) with stannous octoate as the catalyst and characterized by ¹H NMR spectroscopy, GPC, DSC, TGA, SAXS, and rheometry. The order–disorder transition temperatures (T_ODT) of four PS-b-PLGA block copolymers were determined by temperature sweep measurements and verified by variable-temperature SAXS, which were used to determine the temperature dependence of χ. The χ value of PS-b-PLGA is twice as large as that of poly(styrene-b-racemic lactide) (PS-b-PDLLA) at 150 °C, while the surface energies (γ) of PS and PLGA are nearly equal. Thin films of PS-b-PLGA were successfully directed to assemble on stripe chemical patterns with a range of pattern periods (L_S) upon thermal annealing. SEM analysis of the assembled films revealed that long-range ordered perpendicularly oriented lamellae were registered on chemical patterns with 2× density multiplication. These results qualify PS-b-PLGA as an attractive candidate for next-generation lithography with sub-10 nm resolution.

中文翻译：

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通过热退火在化学图案上定向自组装高 χ 聚（苯乙烯-b-（乳酸-alt-乙醇酸））嵌段共聚物

我们展示了聚（苯乙烯-b-（乳酸-alt-乙醇酸））（PS- b -PLGA）的合成和定向自组装（DSA ）。通过 LGA ( d , l -3 -methyl-1,4-dioxane-2,5-dione) 的开环聚合 (ROP) 从羟基-以辛酸亚锡为催化剂的封端聚苯乙烯（PS-OH），并通过¹ H NMR 光谱、GPC、DSC、TGA、SAXS 和流变仪进行了表征。四个 PS- b的有序-无序转变温度 ( T _{ODT )}-PLGA 嵌段共聚物通过温度扫描测量确定并通过变温 SAXS 验证，用于确定 χ 的温度依赖性。PS- b -PLGA的 χ 值在 150 ℃时是聚（苯乙烯-b-外消旋丙交酯）（PS- b -PDLLA）的两倍，而 PS 和 PLGA 的表面能（γ）接近平等的。PS- b - PLGA薄膜被成功引导组装成具有一系列图案周期的条纹化学图案（L _S) 在热退火时。组装薄膜的 SEM 分析显示，长程有序垂直取向的薄片以 2 倍密度倍增记录在化学图案上。这些结果使 PS- b - PLGA 成为具有低于 10 nm 分辨率的下一代光刻的有吸引力的候选者。