Investigation of liquid pinning on surface nanoscale topography

Capillarity assisted particle assembly (CAPA), is a powerful technique which is gaining in importance. Indeed the application possibilities are vast but, due to its relatively early research stage, the optimal and generic assembly parameters have yet to be investigated. This project aims to set a cornerstone on which to build a reliable and fully regulated CAPA fabrication process. With the current knowledge the issue lies in identifying the transition between optimal accumulation and deposition which often leads to uncontrolled and non-selective deposition of particles on the substrate. By measuring the contact angle we want to predict the evolution of the system which ultimately could lead to a regulation a priori to hinder this catastrophic event. During this project an efficient toolbox was created to allow detection and quantification of small and local changes in receding contact angle through the pinning behaviour of the liquid drop contact line. The program was used to analyse the pinning dependence on geometric parameters of pinning traps at nanoscale. Finally a CAPA was conducted and the pinning behaviour was compared with the trap filling percentage.