State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
ACS Appl Mater Interfaces. 2023 May 3;15(17):21640-21650. doi: 10.1021/acsami.3c02176. Epub 2023 Apr 19.
A macroscopic supramolecular assembly (MSA) refers to non-covalent interactions between building blocks over a micrometer scale, which provides insights into bio-/wet adhesion, self-healing, and so on and new fabrication strategies to heterogeneous structures and bio-scaffolds. The key to realize the MSA of rigid materials is pre-modifying a compliant coating known as a "flexible spacing coating" beneath the interactive moieties. However, available coatings are limited to polyelectrolyte multilayers with shortcomings of tedious fabrication, weak adhesion to substrates, susceptibility to external reagents, and so on. Here, we develop a facile method to induce a new "flexible spacing coating" of a poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogel with electrostatic interactions to achieve MSA of diverse rigid materials (quartz, metal, rubber, and plastics). Selective self-assembly of positive-negative charged surfaces is observed by the naked eye under 3 min of shaking in water, providing strategies to rapid wet adhesion. The interfacial binding force between positive-negative interacted surfaces is 1018.1 ± 299.2 N/m, which is over two magnitudes larger than that of control groups, that is, positive-positive (24.4 ± 10.0 N/m) and negative-negative (67.5 ± 16.7 N/m) interacted surfaces. In situ force measurements and control experiments of identically charged building blocks have strongly supported the improved binding strength and chemical selectivity between interactive building blocks. The coating is advantageous with a simple fabrication, strong adhesion to materials, robust solvent tolerance to assembly solutions, and feasibility of photo-patterning. We envision that the above strategy would broaden the material choices of flexible spacing coatings for efficient MSA and new methods for rapid interfacial adhesion.
宏观超分子组装（MSA）是指在微米尺度上构建基元之间的非共价相互作用，这为生物/湿黏附、自修复等提供了新的见解，并为异质结构和生物支架提供了新的制造策略。实现刚性材料 MSA 的关键是预先修饰一种称为“柔性间隔涂层”的顺应性涂层，该涂层位于相互作用部分下方。然而，现有的涂层仅限于聚电解质多层膜，存在制造繁琐、与基底附着力弱、易受外部试剂影响等缺点。在这里，我们开发了一种简便的方法来诱导具有静电相互作用的聚（2-羟乙基甲基丙烯酸酯）（PHEMA）水凝胶的新“柔性间隔涂层”，以实现多种刚性材料（石英、金属、橡胶和塑料）的 MSA。在水中晃动 3 分钟即可肉眼观察到正负电荷表面的选择性自组装，为快速湿黏附提供了策略。正负相互作用表面之间的界面结合力为 1018.1 ± 299.2 N/m，比对照组（即正正相互作用表面 24.4 ± 10.0 N/m 和负负相互作用表面 67.5 ± 16.7 N/m）大两个数量级。原位力测量和相同电荷构建基块的控制实验强烈支持了改进的相互作用构建基块之间的结合强度和化学选择性。该涂层具有制造简单、与材料附着力强、对组装溶液的溶剂耐受性强以及光图案化的可行性等优点。我们设想，上述策略将拓宽柔性间隔涂层的材料选择范围，以实现高效的 MSA 和新的快速界面黏附方法。
