Electrospray drying-mediated coating of cellulose nanocrystal

Cellulose nanocrystals (CNCs) have garnered significant attention in recent years due to their potential applications in coating, reinforcement, and packaging technologies. The present study focuses on the development of an efficient, low-cost, and scalable drying process for CNCs, adapted from the electrospray technique. CNCs were dispersed in various concentrations of tert‑butanol (t-BuOH) prior to electrospray drying. The resulting morphologies and micro-rheological behaviors were compared to those obtained through conventional air drying, oven drying, freeze-drying, and air-spray drying methods. The electrospray-dried CNCs derived from an 85% t-BuOH suspension exhibited superior physico-chemical properties and thermal stability, characterized by highly ordered crystals that self-assembled into thin lamellar structures. Furthermore, the relatively low re-suspension ability of these dried CNCs is advantageous for coating and thin film fabrication, providing high controllability over the morphology. Notably, this rapid drying process (≤ 35 min) can be extended to other nanomaterials, provided that their suspensions can be electrically charged to spread and dry uniformly on substrates.