Exploration on the regulation of writing performance through Pickering emulsions-coated handmade Xuan paper

Surface sizing (or coating) can significantly improve surface properties and enhance the writing performance of paper products. Pickering emulsion, where the solid particles are used, is applied as a sizing agent due to its insensitivity to external environment and narrow size distributions. This research investigated the writing and printing effect on Xuan paper (a kind of porous handmade paper originating in ancient China used for writing and painting) coated with Pickering emulsion. The morphology and narrow size distribution of alkenyl succinic anhydride-in-water emulsions were characterized by microscopical techniques. Subsequently, these emulsions were applied for surface sizing on Xuan paper, and the surface properties of the sized paper were analyzed by pH values. The obtained data indicates that a series of alkaline-sized paper are successfully produced. The results of static contact angles, whiteness, Fourier transform infrared spectroscopy, and scanning electron microscopy reveal that Pickering emulsion provides a smooth surface for writing on Xuan paper, without significantly changing the whiteness of the paper or affecting the writing quality. In addition, the ink droplets on coated Xuan paper and their diffusion dynamics were recorded and quantitatively described by the radial mean distribution function, which allowed for the simultaneous determination of the diffusion radius, color intensity, diffusion roundness, and spread rate. This work introduces a fresh perspective on the correlation between the paper’s macroscopic properties and writing parameters, and it further enriches the comprehension of Pickering emulsion systems. In addition, this study presents an overview of the theoretical and practical implications of developing a quantitative model for describing writing patterns and providing a novel approach for surface technology, image description, and hydrodynamic diffusion in porous media.