The installation of stimuli-responsive moieties into their main chain maximizes the stimuli response of polymers. Yet, facile and orthogonal synthesis of such complex macromolecules is a daunting challenge, especially for achieving absolute chain-end-group fidelity, monodispersity, and the formation of block copolymers (BCPs). We harness metal-free hydroxyl-yne click and deprotection chemistry to realize monodisperse, sequence-defined oligomers and BCPs featuring α-bisimines as main-chain photoswitches and orthogonally incorporate functional terminal groups (olefins, acrylates, and non-activated alkynes). We reveal the significant influence of the sequence on solution and solid-state material properties, which manifests as a strong odd-even effect on the hydrodynamic volume, glass transition temperature, and BCP domain spacing. The odd-even effect originates from the distinct symmetries of the sequences resulting from our precise synthetic strategy. Thus, our sequence-defined, orthogonal synthesis strategy with near absolute chain-end-group fidelity and wide functional group compatibility paves the way toward complex polymeric materials with precise properties, topology, composition, and main-chain functionalities.

中文翻译：

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序列定义的主链光开关大分子，具有奇偶效应控制特性


将刺激响应部分安装到其主链中，最大限度地提高了聚合物的刺激响应。然而，这种复杂大分子的简单和正交合成是一项艰巨的挑战，尤其是对于实现绝对的链端基团保真度、单分散性和嵌段共聚物 （BCP） 的形成。我们利用无金属羟基-炔点击和脱保护化学来实现单分散、序列定义的低聚物和 BCP，其中 α-二胺作为主链光开关，并正交掺入官能终端基（烯烃、丙烯酸酯和非活化炔烃）。我们揭示了序列对溶液和固态材料性能的显着影响，这表现为对流体动力学体积、玻璃化转变温度和 BCP 畴间距的强烈奇偶效应。奇偶效应源于我们精确的合成策略产生的序列的不同对称性。因此，我们的序列定义的正交合成策略具有近乎绝对的链端基保真度和广泛的官能团兼容性，为具有精确特性、拓扑结构、组成和主链功能的复杂聚合物材料铺平了道路。