Sim Xuan Ming, Chen Chen, Goto Atsushi
Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore.
ACS Appl Mater Interfaces. 2021 May 26;13(20):24183-24193. doi: 10.1021/acsami.1c07195. Epub 2021 May 13.
An iodide-terminated polymer (Polymer-I) is converted to a thiol-terminated polymer (Polymer-SH) using HSCHCHSH in a remarkably short time (10 min). Polymer-SH is further converted to a pyridyl disulfide-terminated polymer (Polymer-SS-Py). The hetero-coupling of Polymer-SH and Polymer-SS-Py is successfully achieved to quantitatively generate a polymer disulfide (Polymer-SS-Polymer). Exploiting this efficient hetero-coupling technique, Polymer-SH is attached (grafted) on a Py-SS-immobilized surface to generate a polymer brush via a disulfide (-SS-) linkage (writing process). The -SS- linkage is cleaved by the treatment with dithiothreitol (DTT) to detach the polymer from the surface (erasing process). Subsequently, another Polymer-SH is attached on the surface to generate another polymer brush (rewriting process). Thus, a writable, erasable, and rewritable polymer brush surface is achieved. Hydrophilic, hydrophobic, and super-hydrophobic polymers (Polymer-SH) are attached on the surface, tailoring the surface wettability in the writing-erasing-rewriting cycles. Polymer-SH is also attached on a chain-end Py-SS-functionalized polymer brush surface, generating a rewritable block copolymer brush surface. A patterned block copolymer brush surface is also obtained using photo-irradiation and a photo-mask in the erasing process. The metal-free synthetic procedure, accessibility to patterned brushes, and switchable surface properties via the writing-erasing-rewriting process are attractive features of the present approach.
碘化物封端的聚合物（聚合物 - I）在极短时间（10分钟）内使用HSCHCHSH转化为硫醇封端的聚合物（聚合物 - SH）。聚合物 - SH进一步转化为吡啶基二硫化物封端的聚合物（聚合物 - SS - Py）。聚合物 - SH和聚合物 - SS - Py的杂化偶联成功实现，定量生成聚合物二硫化物（聚合物 - SS - 聚合物）。利用这种高效的杂化偶联技术，聚合物 - SH附着（接枝）在Py - SS固定化表面上，通过二硫键（-SS-）连接生成聚合物刷（写入过程）。通过用二硫苏糖醇（DTT）处理裂解 - SS - 键，使聚合物从表面脱离（擦除过程）。随后，另一种聚合物 - SH附着在表面上生成另一种聚合物刷（重写过程）。因此，实现了可写、可擦除和可重写的聚合物刷表面。亲水性、疏水性和超疏水性聚合物（聚合物 - SH）附着在表面上，在写入 - 擦除 - 重写循环中调整表面润湿性。聚合物 - SH也附着在链端Py - SS功能化的聚合物刷表面上，生成可重写的嵌段共聚物刷表面。在擦除过程中使用光照射和光掩模也可获得图案化的嵌段共聚物刷表面。无金属合成过程、获得图案化刷的可及性以及通过写入 - 擦除 - 重写过程实现的可切换表面性质是本方法的吸引人之处。
