Contact angle measurement techniques on micro-patterned surfaces: a comparative analysis

摘要

The study of micro-nano patterned surfaces has become a key area in the last few years. While the principal reason behind this interest is the wide range of applications of these surfaces; adhesion and wetting studies also have turned into important areas of research. This is especially important in applications such as biomimetic surfaces, lab-on-chip devices, etc. The study of the contact angle and surface energy is therefore both interesting and crucial In this paper, an attempt is made to compute the contact angle of various substrates using four different methods. Apart from the traditional half angle method and goniometry which are quite well-known, image processing methods based on curve fitting and Hough transforms which have been developed by the authors have been considered for this comparative analysis. In this paper, the Hough transforms-based technique has been discussed in detail. While it is difficult to declare any one technique as the universally best, the pros and cons of all the four algorithms have been discussed in the results section. The algorithms were tested on micro-patterned surfaces fabricated over three different materials: poly dimethyl siloxane (PDMS), polystyrene and acrylic using laser.