Jiadong Chen, Zhenchuan Dong, Mu Li, Xinpei Li, Kun Chen, Panchao Yin*

The explosive growth of binder industry spurs the development of strong adhesives with the integration of multi-functionalities as well as cost-effective and eco-friendly processability. Here, polyvinyl alcohol (PVA) and sub-nanoscale metal oxide cluster, phosphotungstic acid (PTA), both with broad commercial availability, are complexed through hydrogen bonding in water. The obtained nanocomposites demonstrate promising light transmittance and proton conductivity, and most importantly, unprecedentedly high adhesive strengths as ~ 4 kN m^-1 for peeling strength and 8.2 ± 1.7 MPa for single lap shear strength on typical glass substrate. The supramolecular complexation of PVA with PTA can significantly reduce its crystallinity and accelerate PVA chain dynamics for negligible internal stress and membrane shrinkage upon drying, leading to close contact with glass substrates for strong adhesion. Meanwhile, the supramolecular interaction between PVA and PTA contributes to the nanocomposites’ enhanced mechanical strength and resolve the issue of cohesion failure to ensure high adhesive strengths. The fast chain dynamics also benefits rapid proton transportation, contributing to the high proton conductivities. The binder design protocol can be extended to general polymer systems integrated with desired functionalities and allows scale up processing, providing great opportunities for functional adhesives for safety glass and electronic industry.

粘接剂是一种应用广泛的聚合物，随着应用场景不断的复杂化，越来越多的人关注粘接剂的多功能化和使用安全性。聚乙烯醇(PVA)是一种可生物降解的水溶性聚合物，具有优异的力学性能和大量的极性位点，因此可以作为环保型胶水的优质原料。然而PVA胶水一般用在木材、织物等多孔表面的粘合上，在光滑表面(比如玻璃)上的粘接力较低，这是PVA胶水在干燥过程中因结晶产生的残余应力导致的。为了解决这个问题，我们从复合材料的角度出发，在PVA基质中引入亚纳米尺寸的磷钨酸分子簇(PTA)，通过高密度的氢键相互作用使PVA的结晶受到显著的抑制，极大地降低了PVA-PTA复合薄膜的残余应力。该PVA-PTA复合薄膜的剥离强度可以达到纯PVA的20倍以上(~ 4 kN m^-1)，其单搭接剪切强度可达8.2 ± 1.7 MPa。除此之外，PVA-PTA复合薄膜透光率高，还可以实现良好的质子传输，在显示器件领域有极大的应用潜力。这种设计策略不仅可以给其他聚合物体系功能化改性提供参考，其简易的工艺也为实现量产提供了巨大的潜力。

文章信息：Chen, J.; Dong, Z.; Li, M.; Li, X.; Chen, K.; Yin, P.* Ultra-Strong and Proton Conductive Aqua-based Adhesives from Facile Blending of Polyvinyl Alcohol and Tungsten Oxide Clusters. Adv. Funct. Mater. 2022, 2111892. (https://onlinelibrary.wiley.com/doi/10.1002/adfm.202111892)