Axisymmetric Drop Shape Analysis using a low-cost home-made setup

Surface science and engineering gained an increasing importance in recent years, due to the potential benefit they can offer in many applications. An important parameter in this field is the surface wettability, that is in general evaluated by the contact angle. One of the most accurate techniques to measure this quantity is the axisymmetric drop shape analysis, based on the fitting of the theoretical Laplace-Young profile to the contour of experimental drops. In this paper the performance of a simple, low-cost setup - that can be built "at home"- to apply this technique is assessed, also including a detailed analysis about the influence of the most important parameters to set in the procedure. The latter aspect was evaluated by using computer-generated drop profiles and pictures, to have "realistic"images, but for drops of known properties. The experimental setup was built using a desk, a table lamp, a medical syringe, a support for the samples and a "bridge"camera. Measurements were performed on smooth and rough textile surfaces and the results were compared with previous measurements taken with a professional setup. From the comparison it can be affirmed that the performance of the home-made setup is very satisfactory