A Fluorescent, Ultrastrong, Silicon-Containing Polyamide Hot-Melt Adhesive with a Nanocrystalline Structure Similar to Spider Silk

Spider silk is recognized as one of the strongest naturally occurring materials due to its unique biphasic structure. Taking inspiration from natural spider silk, an ultrastrong, low-temperature-resistant, reusable thermoplastic silicon-containing polyamide (Si-PA) hot-melt adhesive (HMA) has been synthesized for the first time by melt polycondensation. The obtained Si-PA adhesive possesses a reliable bond strength of up to 20.6 MPa at ambient temperature and 9.5 MPa at −196 °C on stainless steel, notably outperforming comparable polyamide HMAs. These extraordinary performances mainly originate from the meticulously engineered microphase separation structure, wherein nanoscale crystalline regions (20–200 nm) disperse throughout the amorphous regions formed by organosilicon chain segments. Moreover, high-density hydrogen-bond-induced emission of the amide cluster leads to strong blue fluorescence. The Si-PAs show potential in the fields of cold-resistant adhesive devices and tamper-resistant displays. Furthermore, this design provides an idea for mimicking spider silk materials.蜘蛛丝因其独特的双相结构，被公认为自然界中强度最高的材料之一。本研究受天然蜘蛛丝启发，通过熔融缩聚（melt polycondensation）法首次合成了一种超强、耐低温、可重复使用的热塑性含硅聚酰胺（silicon-containing polyamide, Si-PA）热熔胶（hot-melt adhesive, HMA）。所制备的Si-PA胶黏剂在不锈钢基材上表现出可靠的粘接强度：室温下可达20.6 MPa，在−196 ℃时仍有9.5 MPa，显著优于同类聚酰胺热熔胶。该优异性能主要源于其精心构建的微相分离结构，其中纳米级晶区（20~200 nm）均匀分散于有机硅链段形成的非晶区中。此外，酰胺团簇的高密度氢键诱导发光效应使其产生强烈的蓝色荧光。该类Si-PA材料在耐低温胶黏器件及防篡改显示屏领域具有应用潜力。同时，此设计思路也为仿生蜘蛛丝类材料的研发提供了新的借鉴方向。