Thinning air-water films stabilized by bacterial particles

• 作者: Song Wu Yuehua Yang Hongyuan Jiang
• 来源期刊: 力学学报（英文版）
• 年，卷（期）: 2021,（1）
• 所属期刊栏目: X-MECHANICS
• 页码范围: 27-34
• 页数: 8页
• 语种: 英文

摘要

The ability of particles to stabilize liquid films has broad applications in many fields,such as drug delivery,biofuel catalysis,and crude-oil separation.The mechanism of particles to stabilize emulsions has been widely studied.However,how particles affect the stability of suspension films is still unclear.Here,the dynamics of bacterial particles on free liquid films during evaporation is obtained by direct microscopic observation.We find that the initial concentration of the bacterial solution affects the evolution of the shapes and stabilities of liquid films.The liquid film with a low bacterial concentration exhibits a drainage and rupture process similar to pure water,and bacteria would be evacuated during the evaporation of liquid film.However,when the bacterial concentration is high,bacteria form a single-layer array in the center of the film and greatly enhance the stability of the liquid film.We demonstrate that these two distinct film evaporation dynamics are caused by the difference in the lateral capillary force of the particles at different positions on the liquid film,which is not affected by the active motility of particle.Together,our research reveals the critical role of bacteria concentration in stabilizing suspension liquid film.