Department of Chemistry , Tufts University , 62 Talbot Avenue , Medford , Massachusetts 02155 , United States.
Langmuir. 2019 Oct 29;35(43):13791-13804. doi: 10.1021/acs.langmuir.9b02005. Epub 2019 Sep 27.
Layer-by-layer (LbL) self-assembly of polymer coatings is a bottom-up fabrication technique with broad applicability across a wide range of materials and applications that require control over interfacial properties. While most LbL coatings are chemically uniform in directions both tangent and perpendicular to their substrate, control over the properties of surface coatings as a function of space can enhance their function. To contribute to this rapidly advancing field, our group has focused on the top-down spatiotemporal control possible with photochemically reactive LbL coatings, harnessed through charge-shifting polyelectrolytes enabled by photocleavable ester pendants. The photolysis of the photocleavable esters degrades LbL films containing these polyelectrolytes. The chemical structures of the photocleavable groups dictate the wavelengths responsible for disrupting these coatings, ranging from ultraviolet to near-infrared in our work. In addition, spatially segregating reactive groups into "compartments" within LbL films has enabled us to fabricate reactive free-standing polymer films and multiheight photopatterned coatings. Overall, by combining bottom-up and top-down approaches, photoreactive LbL films enable precise control over the interfacial properties of polymer and composite coatings.
层层自组装（LbL）聚合物涂层是一种自下而上的制造技术，具有广泛的适用性，适用于需要控制界面性能的各种材料和应用。虽然大多数 LbL 涂层在垂直和平行于其基底的方向上化学均匀，但控制表面涂层的性质作为空间的函数可以增强其功能。为了促进这一快速发展的领域，我们的研究小组专注于光化学反应性 LbL 涂层的自上而下的时空控制，通过光可裂解酯侧链赋予的电荷转移聚电解质来实现。光可裂解酯的光解会降解含有这些聚电解质的 LbL 薄膜。光可裂解基团的化学结构决定了负责破坏这些涂层的波长，在我们的工作中从紫外线到近红外光。此外，将反应性基团在 LbL 薄膜内“分隔”成“隔室”，使我们能够制造反应性独立聚合物薄膜和多高度光图案化涂层。总的来说，通过结合自上而下和自下而上的方法，光反应性 LbL 薄膜能够精确控制聚合物和复合材料涂层的界面性质。
