A series of amphiphilic ionic peptoid block copolymers where the total number (1 or 3) and position of ionic monomers along the polymer chain are precisely controlled have been synthesized by the submonomer method. Upon dissolution in water at pH = 9, the amphiphilic peptoids self-assemble into small spherical micelles having hydrodynamic radius in ∼5-10 nm range and critical micellar concentration (CMC) in the 0.034-0.094 mg/mL range. Small-angle neutron scattering (SANS) analysis of the micellar solutions revealed unprecedented dependence of the micellar structure on the number and position of ionic monomers along the chain. It was found that the micellar aggregation number ( Nagg) and the micellar radius ( Rm) both increase as the ionic monomer is positioned progressively away from the junction of the hydrophilic and hydrophobic segments along the polymer chain. By defining an ionic monomer position number ( n) as the number of monomers between the junction and the ionic monomer, Nagg exhibited a power law dependence on n with an exponent of ∼1/3 and ∼3/10 for the respective singly and triply charged series. By contrast, Rm exhibited a weaker dependence on the ionic monomer position by a power law relationship with an exponent of ∼1/10 and ∼1/20 for the respective singly and triply charged series. Furthermore, Rm was found to scale with Nagg in a power-law relationship with an exponent of 0.32 for the singly charged series, consistent with a weakly charged ionic star-like polymer model in the unscreened regime. This study demonstrated a unique method to precisely tailor the structure of small spherical micelles based on ionic block copolymers by controlling the sequence and position of the ionic monomer.

中文翻译：

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序列定义的离子类肽嵌段共聚物的溶液自组装

通过亚单体法合成了一系列两亲性离子类肽嵌段共聚物，其中离子单体的总数（1 或 3）和沿聚合物链的位置受到精确控制。在 pH = 9 的水中溶解后，两亲性类肽自组装成小球形胶束，其流体动力学半径在 5-10 nm 范围内，临界胶束浓度 (CMC) 在 0.034-0.094 mg/mL 范围内。胶束溶液的小角中子散射 (SANS) 分析揭示了胶束结构对沿着链的离子单体的数量和位置的前所未有的依赖性。发现胶束聚集数 (Nagg) 和胶束半径 (Rm) 都随着离子单体沿着聚合物链逐渐远离亲水和疏水链段的连接点而增加。通过将离子单体位置数 (n) 定义为连接点和离子单体之间的单体数，Nagg 表现出对 n 的幂律依赖性，其中指数分别为 1/3 和 3/10，分别为单个和三个充电系列。相比之下，根据幂律关系，Rm 对离子单体位置的依赖性较弱，对于各自的单电荷和三电荷系列，指数分别为~1/10 和~1/20。此外，发现 Rm 与 Nagg 呈幂律关系，单电荷系列的指数为 0.32，与未筛选状态下的弱带电离子星状聚合物模型一致。该研究展示了一种独特的方法，可以通过控制离子单体的序列和位置来精确定制基于离子嵌段共聚物的小球形胶束的结构。