A Test Device for Microalgal Antifouling Using Fluctuating pH Values on Conductive Paints

Due to the current dependence on biocidal antifouling coatings for biofouling control, there is a continuing international challenge to develop more environmentally acceptable antifouling systems. Fluctuating the pH values on paint surfaces is one of these approaches. We developed an antifouling test device to investigate algal biofilms on conductive paints by using a flume with electrochemically working test panels and subsequent confocal laser scanning microscopy (CLSM) of biofilms. By employing a pole reversal of direct current, fluctuating pH values on the paint surface were generated. As a consequence of the resulting pH stress, colonization of the paint surface by diatoms decreased substantially. The density of biofilm algae decreased with increasing pH fluctuations. However, breaks between electrochemical treatments should not exceed one hour. Overall, we established an experimental setup for testing the antifouling capabilities of electrodes based on conductive paints, which could be used for further development of these varnishes.