Contact angle determination inside closed microfluidic channels

Microfluidic channels often require coating with an SAM from the inside, e.g. to achieve a hydrophobic surface or to allow immobilization of biomolecules. To assess the quality of a coating, its contact angle is a key parameter. The most common method for contact angle measurement is the static, direct sessile drop method, where a droplet of a liquid is added to a surface and a photo is taken, wherefrom the contact angle is determined. However, this method is not possible inside closed microfluidic channels. Therefore, the goal of this Master thesis is to investigate the application of a new dynamic method, which calculates the contact angle from the flow speed of a liquid inside the channel. This will lead to a contact angle profile through the channel with high resolution, allowing to assess the SAM coating quality and homogeneity. Once successfully established, several projects and approaches related to Life Science will profit from this new method.