Institut des Matériaux and Institut des Sciences et Ingénierie Chimiques, Laboratoire des Polymères, École Polytechnique Fédérale de Lausanne (EPFL), Batiment MXD, Station 12, CH-1015 Lausanne, Switzerland.
J Am Chem Soc. 2021 Dec 1;143(47):19873-19880. doi: 10.1021/jacs.1c09187. Epub 2021 Nov 18.
Surface-initiated polymerization reactions are a powerful tool to generate chain-end-tethered polymer brushes. This report presents a synthetic strategy that gives access to structurally well-defined hydrocarbon polymer brushes of controlled molecular weights, which can be further modified to generate more complex surface-attached polymer architectures. The hydrocarbon brushes reported in this study are polymethylene brushes that are obtained via surface-initiated C1 polyhomologation of dimethylsulfoxonium methylide. The strategy outlined here is based on the use of an alkylboronic acid pinacol ester initiator, which allows for controlled, unidirectional chain growth by monomer insertion into only the C-B bond of the initiator and which presents the polymerization active group at the growing polymer chain end. This surface-initiated C1 polyhomologation methodology is compatible with photopatterning strategies and can be used to generate micropatterned polymethylene brush films. Furthermore, conversion of the boronic ester chain-end functionalities to hydroxyl groups allows for selective chain-end modification and enables access to a variety of surface-anchored block copolymer architectures by chain extension via, for example, ring-opening or atom transfer radical polymerization chemistries.
表面引发聚合反应是生成链端固定聚合物刷的有力工具。本报告提出了一种合成策略，可获得结构明确的、分子量可控的碳氢聚合物刷，进一步修饰可生成更复杂的表面附着聚合物结构。本研究中报道的碳氢聚合物刷是通过二甲基亚砜甲基叶立德的表面引发 C1 同系聚合得到的聚亚甲基刷。这里概述的策略基于使用烷基硼酸频哪醇酯引发剂，通过单体仅插入引发剂的 C-B 键进行可控的、单向链增长，并且在聚合物链端呈现聚合活性基团。这种表面引发的 C1 同系聚合方法与光图案化策略兼容，可用于生成微图案化的聚亚甲基刷膜。此外，将硼酸酯链端官能团转化为羟基，可实现选择性链端修饰，并可通过例如开环或原子转移自由基聚合化学进行链延伸，从而获得各种表面锚定的嵌段共聚物结构。
