特殊浸润性表面的液滴凝结

以铝片为基底, 经电化学腐蚀和沸水处理制备了多级微纳米结构; 通过气相沉积和涂油分别制备了超疏水表面、 疏水超润滑(slippery)表面和亲水slippery表面; 探究了表面不同的特殊浸润性(超亲水、 超疏水、 疏水slippery和亲水slippery)对液滴凝结的影响. 结果表明, 超亲水表面的液滴凝结属于膜状冷凝, 超疏水表面和slippery表面的液滴凝结均属于滴状冷凝. 超疏水表面液滴合并时, 合并的液滴会不定向弹离表面. 疏水slippery表面和亲水slippery表面由于表面浸润性的不同导致液滴成核密度和液滴合并的差异, 亲水slippery表面凝结液滴的最大体积远大于疏水slippery表面凝结液滴的最大体积. 4种表面的雾气收集效率由大到小依次为亲水slippery表面>疏水slippery表面>超亲水表面>超疏水表面.

Droplet Condensation on Surfaces with Special Wettability†

The surfaces with micro/nano structures were fabricated by electrochemical corrosion and then boiling water treatment. Superhydrophobic surface was fabricated by chemical vapor deposition. Hydrophobic and hydrophilic surfaces were fabricated by coating surfaces with silicon oil and hydroxy-terminated silicon oil. Condensation on these surfaces (superhydrophilic, superhydrophobic, hydrophobic slippery and hydrophilic slippery) were investigated. Superhydrophilic surfaces show filmwise condensation. Both super hydrophobic and slippery surfaces show dropwise condensation. Superhydrophobic surfaces show out-of-plane jumping motion of the coalesced drops. Due to the wettability difference between the hydrophobic slippery surface and hydrophilic surface, fast droplet coalescence on hydrophilic slippery surfaces can effectively increase the droplet volume over time. The fog harvesting rates of different surfaces ranged in turn are hydrophilic slippery, hydrophobic slippery, superhydrophilic and superhydrophobic.