CAJ | 학술논문

亲水玻璃基片在掩模板的保护下，通过喷涂超疏水层，得到了被疏水层包围的圆形亲水区域。胶体液滴在这一区域被很好地限制，并且液滴体积可以在较大范围内变化，体积的变化可以改变液滴与基片的表观接触角。通过显微观察手段原位观察了表观接触角为疏水的受限胶体液滴蒸发过程中粒子沉积行为。在整个蒸发过程中，受限液滴边界被钉扎在亲疏水交界处。粒子沉积过程中，驱动粒子的液滴内部流动会发生变化。粒子沉积图案形成过程由三种流体行为控制，最初， Marangoni效应占主导作用，驱动粒子在液滴表面聚集，随之沉积到液滴边缘；随着蒸发进行，当接触角变小(<60?)时，由于边界蒸发速度更快导致的毛细补偿流使得粒子直接向边界沉积。在干燥的最后阶段，亲水区域内的液层变得很薄，只有一单层粒子存在于这一薄液层中，蒸发继续进行时，薄液层发生失稳使得粒子迅速聚集而形成网络化图案，由于粒子间距变小，球间的液桥毛细力也会参与到这一聚集过程中。
친수파리기편재엄모판적보호하，통과분도초소수층，득도료피소수층포위적원형친수구역。효체액적재저일구역피흔호지한제，병차액적체적가이재교대범위내변화，체적적변화가이개변액적여기편적표관접촉각。통과현미관찰수단원위관찰료표관접촉각위소수적수한효체액적증발과정중입자침적행위。재정개증발과정중，수한액적변계피정찰재친소수교계처。입자침적과정중，구동입자적액적내부류동회발생변화。입자침적도안형성과정유삼충류체행위공제，최초， Marangoni효응점주도작용，구동입자재액적표면취집，수지침적도액적변연；수착증발진행，당접촉각변소(<60?)시，유우변계증발속도경쾌도치적모세보상류사득입자직접향변계침적。재간조적최후계단，친수구역내적액층변득흔박，지유일단층입자존재우저일박액층중，증발계속진행시，박액층발생실은사득입자신속취집이형성망락화도안，유우입자간거변소，구간적액교모세력야회삼여도저일취집과정중。
A circular silicone sheet as a masker was used to cover a glass slide, and then the super-hydrophobic coating was sprayed on the glass slide free of silicone sheet masker, thus a round hydrophilic area surrounded by a super-hydrophobic coating is obtained. The PS colloidal droplets are confined in the hydrophilic area, and the droplet volume can be changed within a large range. Variation of the droplet volume influences the initial apparent contact angle. We investigate the particle deposition behavior of the confined colloidal droplet for a hydrophobic apparent contact angle in evaporation process by using an in situ optical observation system. In the whole evaporation process the contact-line of the confined droplet is pinned at the junction between the hydrophilic area and hydrophobic area. In the particle deposition process the main driving flow is different, and the final deposition pattern is controlled by three flow behaviors. In the early stage, the main flow is the Marangoni flow, which drives the particle clusters float on the droplet surfaces, part of them accumulated at the boundaries. As the evaporation proceeds, when the apparent contact angle decreases (<60?), the evaporation flux becomes singular near the contact line, Capillary flow towards the contact inside the drop as a compensation to the solvent loss at the drop boundary, which drives the particles in the droplet to rapidly accumulate at the contact-line. In the last evaporation stage, the thickness of the film in the hydrophilic area becomes very thin, and there is only one layer of particles in this thin film, the thin liquid film instability triggers the particles in the middle area to rapidly aggregate and then form a kind of network pattern, due to the decrease of distances between the particles. Capillary force between particles also takes part in this aggregate process.