Combination of microsized mineral particles and rosin as a basis for converting cellulosic fibers into "sticky" superhydrophobic paper.

The unique features of cellulosic paper including flexibility, biodegradability, and low cost enables it as a versatile, sustainable biomaterial for promising applications. In the paper industry, microsized mineral particles are widely used in the production of printing/writing paper grades, while rosin derived from trees is the earliest internal sizing agent for paper hydrophobication. On the basis of existing commercial practices associated with the use of mineral particles and rosin in paper production, we present a process concept of converting cellulosic fibers (paper-grade pulp) into "sticky" superhydrophobic paper involving the use of microsized mineral particles and rosin (a tree-derived natural product, mainly a mixture of resin acids, especially abietic acid with chemical formula of C19 H29 COOH). Internal filling of cellulosic networks with mineral particles was basically used to hold out the mineral particles added at the surface, and the delicate integration of wet-end/surface applications of mineral particles with paper surface engineering with rosin/alum led to the development of "sticky" superhydrophobicity, i.e., ultrahigh water-repellency and strong adhesion to water. This proposed concept may provide valuable implications for expanding the use of paper-based products to unconventional applications, e.g., ultrahigh-performance ink jet printing paper for mitigating the "coffee-ring effect" and paper-based microfluidic devices for biomedical testing.