Poly(aminobenzeneboronic acid)-mediated rapid self-healing and shape memory cellulose crystal nanohydrogels.

Poly(aminobenzeneboronic acid)-cellulose nanocrystals (PABA@CNCs) mediated self-healing and shape memory hydrogels are reported for the first time. PABA@CNCs are designed as efficient crosslinker, light-to-heat generator and strengthening agent in hydrogel. CNCs within dual crosslinking networks characterized by physical microcrystallization and dynamic covalent boronic bonds endow robust mechanical strength (tensile stress of 224 kPa) whose tensile stresses are 18 times higher than the single component PVA hydrogel. Reversible microcrystallization-induced fast and efficient self-healing behavior (healing efficiency ≥96.0 %) is easily obtained by exposing the hydrogel to a near-infrared (NIR) laser within 2 min. PABA@CNCs, a superior light-to-heat generator, is responsible for above melting-crystallization process. Meanwhile, the shape memory property with a shape fixity and recovery ratio of 88.9 % and 81.9 % are validated under fast pH-responsive boronic bonds between PABA@CNCs and PVA. In addition, the as-prepared hydrogel shows excellent affinity to a L929 cell, whose cell viability is higher than 95 %.