2016.01.18《Underwater contact adhesion and microarchitecture in polyelectrolyte complexes actuated by solvent exchange》
在发表于《Nature Materials》的这项研究中，作者受沙堡蠕虫粘附启发，将水下粘附策略从单纯依赖强黏附官能团的材料设计，推进到由溶剂交换精细调控聚电解质相分离的新粘附机制，在水下粘附剂与仿生材料领域引发了深远的理念变革。该研究依托高精度表面力仪（SFA）及多种谱学手段，首次在实验上展示了水-DMSO溶剂交换触发聚电解质复合、实现快速水下粘附的过程：低介电常数DMSO溶剂中质子化的聚阴离子接触水分子后快速去质子化，瞬间激活与聚阳离子的静电复合作用，形成凝聚态中间相，进而相分离固化出纳米多孔结构。得益于从纳米到宏观尺度的三重力学协同作用，即静电作用提升体相内聚力、儿茶酚基团赋予界面粘附力、相分离多孔纳微结构实现增韧增强，新型粘附剂实现了无需外加压力、无需预固化、可耐受高压水冲击与沸水浸泡的水下快速固化粘附。总体而言，该研究不仅展示了一种全新的水下粘附设计理念，也明晰了溶剂交换调控静电力、触发聚电解质相分离的界面物理机制，为仿生水下粘附、凝聚态相分离及生物湿粘合界面的理性设计提供了普适性物理化学基础。
第一作者：Qiang Zhao, Dong Woog Lee, B. Kollbe Ahn；通讯作者：Jacob N. Israelachvili，J. Herbert Waite
In this study published in Nature Materials, the authors were inspired by the adhesion of sandcastle worms and advanced underwater adhesion strategies from material design relying solely on strong adhesion functional groups to a new adhesion mechanism that finely regulates polyelectrolyte phase separation through solvent exchange. This has sparked a profound conceptual change in the field of underwater adhesives and biomimetic materials. This study relies on high-precision surface force analyzer (SFA) and various spectroscopic methods to experimentally demonstrate for the first time the process of water DMSO solvent exchange triggering polyelectrolyte composite and achieving rapid underwater adhesion: protonated polyanions in low dielectric constant DMSO solvent rapidly deprotonate upon contact with water molecules, instantly activating electrostatic recombination with polycations to form a condensed intermediate phase, which then separates and solidifies into a nanoporous structure. Thanks to the synergistic effect of triple mechanics from the nanoscale to the macroscopic scale, namely the electrostatic effect enhances the cohesive force of the body phase, the catechol group endows the interface adhesion force, and the phase separation of porous nano microstructures achieves toughening enhancement, the new adhesive achieves rapid underwater curing adhesion without external pressure, pre curing, and resistance to high-pressure water impact and boiling water immersion. Overall, this study not only demonstrates a novel underwater adhesion design concept, but also clarifies the interface physical mechanism of solvent exchange regulating electrostatic forces and triggering polyelectrolyte phase separation, providing a universal physical and chemical basis for the rational design of biomimetic underwater adhesion, condensed phase separation, and biological wet bonding interfaces.
First Author：Qiang Zhao, Dong Woog Lee, B. Kollbe Ahn
Corresponding Author：Jacob N. Israelachvili，J. Herbert Waite