Antimicrobial polymer composites with anti-biofouling features for floating solar power plant applications: Effect of zinc oxide nanoparticles

Antimicrobial hybrid polymer composites are developed for application in floating solar power plants. To avoid the degradation of the floater because of microbes living in the water as well as possible biofouling, zinc oxide (ZnO) is used as an antimicrobial agent, varying the weight percent (1, 2, and 3 wt%) within the high-density polyethylene (HDPE) matrix, along with carbon black (CB) as a reinforcing agent (1, 1.5, 2, and 2.5 wt%). Escherichia coli (facultative anaerobic) and Pseudomonas aeruginosa (aerobic-facultatively anaerobic) gram-negative bacteria formed a biofilm on HDPE in a 96-well plate for 5 days. In vitro, biofilm formation was determined by measuring absorbance (A420) in crystal violet dye, and the colony-forming unit (CFU) was determined by the spread plating technique. The biofilm formation and disruption are observed through a scanning electron microscope (SEM), where both the CFU and the SEM revealed uniform formation of biofilm onto neat HDPE. The best performance in terms of reduced biofilm formation and biofouling onto HDPE floaters was achieved for E. coli (ZnO: 2 wt% and CB: 2 wt%), whereas for Pseudomonas aeruginosa (ZnO: 3 wt% and CB: 2 wt%). Application of greener polymers and nanoparticles for future studies is highly recommended.