Photo-/electro-chromic underwater adhesive coacervate from self-assembly of zwitterions and polyoxometalate

Wet/underwater adhesion is a matter of common occurrence to some marine organisms, but it is a quite thorny problem in practical engineering field and even in our daily lives. Meanwhile, preparation of an instantly available underwater adhesive with good adhesion strength is another great challenge. Herein, inspired by the oppositely charged polyelectrolytes coacervate of sandcastle worm glue, a zwitterion-based self-assembled underwater adhesive coacervate is reported. This coacervate can be deployed in real-time by mixing together of zwitterionic poly (HEMA-co-SBMA) (PHS), silicotungstic acid (STA) and arginine (Arg). It is an entirely new construction strategy via synergistical self-assembly of low- and high-molecular-weight zwitterions and polyanions by electrostatic force. The coacervate plays well in underwater adhesion to substrates such as organic plastic and inorganic ceramic. It also achieves outstanding performance in dry substrates, due to multiple interactions formed at the interface of adhesive coacervate and substrate. Moreover, this coacervate shows underwater sealing property and resistance to violent water flush. Additionally, the coacervate possesses electro/photo-chromic properties that may achieve stimuli-responsive color switching, therefore broadening its potential applications for external signals responsive devices like energy-efficient windows, wearable electronics, and warning devices.