Noguera-Marín Diego, Moraila-Martínez Carmen L, Cabrerizo-Vílchez Miguel A, Rodríguez-Valverde Miguel A
Biocolloid and Fluid Physics Group, Applied Physics Department, Faculty of Sciences, University of Granada , E-18071 Granada, Spain.
Langmuir. 2014 Jul 1;30(25):7609-14. doi: 10.1021/la501416u. Epub 2014 Jun 16.
Better control of colloidal assembly by convective deposition is particularly helpful in particle templating. However, knowledge of the different factors that can alter colloidal patterning mechanisms is still insufficient. Deposit morphology is strongly ruled by contact line dynamics, but the wettability properties of the substrate can alter it drastically. In this work, we experimentally examined the roles of substrate contact angle hysteresis and receding contact angle using driven evaporating menisci similar to the dip-coating technique but at a low capillary number. We used smooth substrates with very different wettability properties and nanoparticles of different sizes. For fixed withdrawal velocity, evaporation conditions, and nanoparticle concentration, we analyzed the morphology of the deposits formed on each substrate. A gradual transition from stripe-like patterns to a film was observed as the contact angle hysteresis and receding contact angle were lowered.
通过对流沉积更好地控制胶体组装在颗粒模板化中特别有帮助。然而，对于能够改变胶体图案化机制的不同因素的了解仍然不足。沉积物形态在很大程度上受接触线动力学支配，但基底的润湿性可以极大地改变它。在这项工作中，我们使用类似于浸涂技术但毛细管数较低的驱动蒸发弯月面，通过实验研究了基底接触角滞后和后退接触角的作用。我们使用了具有非常不同润湿性的光滑基底和不同尺寸的纳米颗粒。对于固定的提拉速度、蒸发条件和纳米颗粒浓度，我们分析了在每个基底上形成的沉积物的形态。随着接触角滞后和后退接触角降低，观察到从条纹状图案到薄膜的逐渐转变。
