The self-assembly of sequence-defined polymers (SDPs) enables the formation of a diverse array of nanostructures; however, the construction of complex hierarchical structures via thermal annealing from SDPs remains relatively unexplored. In this study, two series of oligourethanes, 2Cit-pB_n-OH and 2Cit-mB_n-OH, were synthesized to investigate their thermal annealing behaviors. Nanorod clusters were generated from 2Cit-pB₆-OH in a mixture of 1,4-dioxane and toluene, whereas 2Cit-pB₈-OH formed nanosheets after thermal annealing. Upon modifying the structure of the repeating units, 2Cit-mB₆-OH self-assembled into ultrathin nanosheets, transitioning from nanospheres after thermal annealing in a mixture of isopropanol and cyclohexane, while “flower” micelles were produced from 2Cit-mB₈-OH. Interestingly, when isopropanol was replaced with a mixture of isopropanol and tetrahydrofuran (THF), uniform nanotubes were generated by 2Cit-mB₆-OH under the same thermal annealing conditions. Additionally, a discrete amphiphile (2Cit-mB₄-(S)DPEG) was synthesized, leading to the formation of uniform nanosheets in aqueous solution after thermal annealing. This work highlights the significant effects of sequence and repeating unit structure of SDPs on their self-assembly behaviors and presents a novel strategy for the controlled fabrication of unique nanostructures from SDPs.

中文翻译：

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通过热退火从离散的寡氨基甲酸酯中受控制备不同的纳米结构


序列定义聚合物 （SDP） 的自组装能够形成多种纳米结构;然而，通过 SDP 的热退火构建复杂的分层结构仍然相对未被探索。在这项研究中，合成了两个系列的寡氨基甲酸酯，2Cit-p B_n-OH 和 2Cit-m B_n-OH，以研究它们的热退火行为。纳米棒簇由 2Cit-p B_6-OH 在 1,4-二恶烷和甲苯的混合物中生成，而 2Cit-p B_8-OH 在热退火后形成纳米片。在修改重复单元的结构后，2Cit-m B_6-OH 自组装成超薄纳米片，在异丙醇和环己烷的混合物中热退火后从纳米球过渡，而“花”胶束则由 2Cit-m B_8-OH 产生。有趣的是，当异丙醇和四氢呋喃 （THF） 的混合物取代异丙醇时，在相同的热退火条件下，2Cit-m B_6-OH 会产生均匀的纳米管。此外，还合成了离散的两亲物 （2Cit-m B₄-（S）DPEG），导致热退火后在水溶液中形成均匀的纳米片。这项工作强调了 SDP 的序列和重复单元结构对其自组装行为的显着影响，并提出了一种从 SDP 受控制造独特纳米结构的新策略。