Development of Anti-Fouling Membranes By Chemical Patterning

Over 1 billion people lack access to clean drinking water.  Membranes are a tool that can help provide clean water to these people. However, treatment of impaired waters for beneficial use exposes the membranes to feed waters containing biological and abiotic species, which leads to fouling and loss of membrane productivity over time. Since reduction in flux due to fouling is one of the largest costs associated with membrane processes in water treatment, new coatings that limit fouling would have significant economic and societal impacts.  Developing these advanced coatings is the focus of our work.

Prior studies in this area largely have focused on chemical modifications to the membrane surface that either prevent microorganisms from attaching or that kill the microorganisms once they do attach.  Based on considerable literature and experience, we know that chemical modification strategies alone can be effective but not sufficient for controlling biofouling.  A more recent area of research is nano-patterning the membrane surface.  Nature provides many examples where structured features can prevent accumulation of ‘foulant’ materials on the surface (i.e., shark skin, lotus leaves, etc.).  Our hypothesis is that combining these two methods (chemical coating and patterning) will yield membrane surfaces that are more effective at biofouling control than either method alone.  This strategy is unique in its use of both chemical coating and patterning to combat biofouling.

In this contribution, we will introduce the methodology used to pattern membrane surfaces with the anti-fouling coating.  We will demonstrate the feasibility of this methodology through AFM, SEM, and attenuated total reflectance (ATR)-FTIR measurements.  Subsequently, we will test our hypothesis in bacterial deposition and membrane biofouling experiments using appropriate model systems.