激光加工逆重力液滴单向传输功能表面

Transmission Function Surface of Laser Processing Anti-gravity Droplet Unidirectional

液滴单向传输在雾收集、反重力输水、微流体控制等领域得到广泛应用。结合纳秒激光刻蚀和化学修饰在铜表面制备逆重力液滴单向传输功能表面。研究润湿性差异及孔径大小对液滴单向传输的影响。研究发现,两侧表面润湿性差值达到一定值时,液滴可以逆重力由疏水表面传输至亲水表面且无法反向传输。差值越大,液滴传输效率越好。微结构形成的疏水表面对液滴传输具有促进作用。液滴传输效率随孔径减小先增大后减小。当孔径为0.6 mm时,液滴传输效率最优。分析可知,液滴逆重力单向传输的动力来源于润湿差异引起的表面张力及毛细作用力。

One-way transmission of droplets is widely used in fields such as mist collection,anti-gravity water delivery,and microfluidic control. Combining nanosecond laser etching and chemical modification,the anti-gravity droplet unidirectional transmission function surface is prepared on the brass surface. The effect of the difference in wettability and the size of the pore size on the unidirectional transport of droplets are researched. It is found that when the difference in wettability on both sides reaches a certain value,the droplets can be transported from the hydrophobic surface to the hydrophilic surface against gravity and cannot be transported in the reverse direction. The larger the difference,the droplet transfer efficiency is better. The hydrophobic surface formed by the microstructure can promote the transport of droplets. The droplet transport efficiency is firstly increased and then decreased with the decrease of the pore size. When the aperture is 0.6 mm,the droplet transfer efficiency is the best. The analysis shows that the power of the droplet’s unidirectional transmission against gravity come from the surface tension and capillary force caused by the difference in wetting.