Underlying molecular mechanism of topical fluid foam with microsphere assistance

Topical fluid foam has a considerable application value in the field of topical medicine due to benefits such as simple uniform distribution on the skin’s surface, ease of use, and good patient compliance. The longevity of topical fluid foam is crucial in assessing its therapeutic success, particularly in complicated heat and salt settings. Nanoparticles could improve the stability of topical fluid foam, but their density, size, homogeneity, and surface characteristics are difficult to be taken into consideration simultaneously, resulting in the unclear underlying molecular mechanism. In this work, the raspberry-like microspheres (RM) with a high cross-linked structure were synthesized using a simple one-step dispersion polymerization. The stabilizing foam function of RM in fluid foam was connected to their size, surface chemical characteristics, and foaming temperature. The effect of gravity on foam stability induced by liquid flow acceleration of RM competed fiercely with their size and surface chemical characteristics, and this competitive connection was highly influenced by temperature. The unique surface properties of RM1 (polymerization time of 1h) allowed for their irreversible adsorption at the gas-liquid interface following sodium dodecyl sulfate (SDS) adsorption. RM1 could counteract the harmful effect of gravity on foam stability at a high temperature of 60 oC, enhancing the surface elasticity of the liquid film and improving foam stability. This work is a fantastic starting point for the development of novel nanomaterials to improve the stability of topical fluid foam for pharmaceutical and medical applications.