论文标题
使用添加的液体抑制硬颗粒涂层中的干燥缺陷
Using an added liquid to suppress drying defects in hard particle coatings
论文作者
论文摘要
假设：硬粒子涂层干燥期间的横向积累和膜缺陷是一个常见问题，通常使用聚合物添加剂和表面活性成分解决，这需要进一步处理干膜。毛细管悬浮液具有可调的物理特性（没有聚合物），在产生均匀和缺陷的无颗粒涂层方面提供了新的途径。 实验：我们研究了少量二次液体对涂层干燥行为的影响。同时测量了温度和湿度控制的干燥室中的应力增加和体重减轻。随着时间的推移，涂料的反射率和高度轮廓的变化与体重减轻和应力曲线有关。 发现：毛细管悬浮液均匀干燥而没有缺陷。高屈服应力抑制了侧向干燥，从而导致涂层收缩到均匀的高度。颗粒之间的桥梁可防止空气侵袭并延长恒定干燥周期。下层中的液体通过表面孔内的角流传输到界面，导致底物附近的部分干燥层，而上面的孔仍然饱和。使用毛细管悬浮液进行硬粒子涂层会导致更均匀的无缺陷膜具有更好的印刷特性，从而使高添加含量过时。
Hypothesis: Lateral accumulation and film defects during drying of hard particle coatings is a common problem, typically solved using polymeric additives and surface active ingredients, which require further processing of the dried film. Capillary suspensions with their tunable physical properties, devoid of polymers, offer new pathways in producing uniform and defect free particulate coatings. Experiments: We investigated the effect of small amounts of secondary liquid on the coating's drying behavior. Stress build-up and weight loss in a temperature and humidity controlled drying chamber were simultaneously measured. Changes in the coating's reflectance and height profile over time were related with the weight loss and stress curve. Findings: Capillary suspensions dry uniformly without defects. Lateral drying is inhibited by the high yield stress, causing the coating to shrink to an even height. The bridges between particles prevent air invasion and extend the constant drying period. The liquid in the lower layers is transported to the interface via corner flow within surface pores, leading to a partially dry layer near the substrate while the pores above are still saturated. Using capillary suspensions for hard particle coatings results in more uniform, defect free films with better printing characteristics, rendering high additive content obsolete.
