Morphology Control of Porous Cellulose Particles by Tuning the Surface Tension of Media during Drying

We previously reported the preparation of cellulose particles by the solvent releasing method (SRM). The obtained cellulose particles had a porous structure filled with a surrounding medium. However, the structure was fragile and easily collapsed because of the capillary pressure as the medium evaporated, resulting in dense cellulose particles. To control the morphology of the cellulose particles in a dry state, we focused our study on the influence of the surface tension of the surrounding medium on the structure of cellulose particles because the capillary pressure is proportional to the surface tension. Different media such as toluene, acetone, and pentane were investigated. The morphologies of the resulting cellulose particles were estimated by volume changes, specific surface areas, and compressive strengths. From these results, as the surface tension of the media filling the particles was lowered, the particle's specific surface area increased, resulting in the formation of softer particles.