Self-assembly behavior and adhesive performance of imidazolium cation grafted cellulose nanocrystals in confined space

Key Words:DROPLET EVAPORATION; COFFEE-RINGS; PATTERNS

Abstract:Confined evaporation-induced self-assembly (C -EISA) is a powerful technique to guide disordered nanoparticles into long -range organized structures. Herein, we investigate the C -EISA behavior of 1-butyl-3-vinylimidazolium cation ([VBIm] + ) grafted cellulose nanocrystals (CNC-C) in a parallel-plates confined geometry. Interestingly, CNC-C can spontaneously assemble into maze-like patterns with branch dimensions on the micrometer scale and uniformly distributed throughout the confined space, which is completely different from the lamellar selfassembly patterns of unmodified CNCs. Combining in situ observations and microscopic characterization, we speculate that the formation of maze-like patterns originates from the reduction of colloidal stability induced by the grafted imidazolium cations. The electrostatic attraction between CNC-C aggregated bundles and glass substrates acts as anchor points, thereby leading to the unstable motion of the liquid-air menisci during the inward intrusion of air. Due to the physicochemical properties and unique C -EISA behavior, the CNC-C based adhesive can maintain adhesion at temperatures of ca. 200 degrees C, while rapidly debonding when immersed in water, demonstrating the potential to be used as stimuli-responsive temporary or removable adhesives. Furthermore, the strategy proposed in this work for achieving CNCs patterning is also promising to be extended to other anisotropic rod-shaped nanoparticles.

Volume:336

Issue:

Translation or Not:no