水下超疏油性壳聚糖-SiO_2复合膜的制备与性能

Preparation and Properties of Chitosan-SiO_2 Composite Films with Underwater Superoleophobicity

利用壳聚糖和亲水性SiO2纳米颗粒,通过浸渍提拉法在玻璃表面制备了水下超疏油壳聚糖-SiO2复合膜.采用扫描电镜、原子力显微镜和接触角仪,研究了组分配比、浸泡时间对复合膜表面形貌、粗糙度、水下油滴接触角(OCA)和滚动角(SA)的影响.结果表明,随着亲水性SiO2含量的增加,复合膜表面聚集的亲水性SiO2纳米颗粒增多,水下疏油性提高;随着浸泡时间延长,复合膜的水下油滴OCA逐渐增大,浸泡168 h时略有减小,SA也受到浸泡时间的影响.当SiO2乙醇悬浮液和壳聚糖溶液的体积比为1∶10和1∶5时,复合膜呈现疏油性;当SiO2乙醇悬浮液和壳聚糖溶液的体积比大于等于1∶2时,复合膜的水下油滴接触角OCA大于150°.当SiO2乙醇悬浮液和壳聚糖溶液的体积比为1∶1、浸泡24 h时,复合膜水下疏油性最好,水下油滴接触角OCA达157.8°,滚动角SA为1.9°.复合膜可用于水下油滴的操控,实现了溴(Br2)和苯乙烯在油滴微反应器中的加成反应.

Underwater superoleophobic composite films containing hydrophilic SiO2 nanoparticles and chitosan were prepared on glass substrates by a simple dip-coating method. By observing the surface morphologies with scanning electron microscope （SEM） and atomic force microscope （AFM） and measuring oil contact angles, factors affecting the morphology, roughness, contact angle and sliding angle of the film, such as the immersion time in the water and the volume ratio of hydrophilic SiO2-ethanol suspension to chitosan solution, were investigated in detail. With the increase of the volume ratio of hydrophilic SiO2-ethanol suspension to chitosan solution,more hydrophilic SiO： powders accumulated on the surfaces of composite films,leading to a significant increase of underwater oleophobicity. With the increase of immersion time in the water, underwater oil contact angle （OCA） of the composite films first increased gradually and then slightly decreased after the films were immersed for 168 h. Meanwhile,the sliding angle （SA） of the films was also affected by the immersion time. When the volume ratio of hydrophilic SiO2-ethanol suspension to chitosan solution was 1 ： 10 and 1 ： 5, the chitosan-SiO2 composite films were oleophobic; and when the volume ratio of hydrophilic SiO2-ethanol suspension to chitosan solution was equal to or higher than 1： 2, the chitosan-SiO2 composite films exhibited underwater superoleophobicity with underwater oil contact angles （OCA） higher than 150°. When the chitosan- SiO2 composite film with the volume ratio of hydrophilic Si02-ethanol suspension to chitosan solution 1：1 immersed in the water for 24 h,it showed an underwater oil contact angle （OCA） 157.8° and sliding angle （SA） 1.9°, exhibiting outstanding underwater superoleophobicity. The chitosan-SiO2 composite films was applied to the manipulation of oil droplets underwater and realized the addition reaction of Br2 and styrene in oil droplet microreactors underwater.