Abundant octadecylamine modified epoxy resin for superhydrophobic and durable composite coating

Abstract

Concretes are generally porous and hydrophilic which lead moisture penetration to corrode metal frame resulting safety concerns. Many attempts to change concrete's wettability were leveraging fluorinated and/or silanized materials that are less environmentally friendly, costly, and non-sustainable. In this study, the epoxy resin and octadecylamine (ODA), two cost effective abundant materials, were combined to form an aqueous hydrophobic slurry as a binder to be mixed into the ordinary Portland concrete (o-concrete). By leveraging the micro/nanostructures in the system, the superhydrophobic concrete composite (SCC) with a water contact angle of 156° and sliding angle of 8° was created. Used as the stucco coating, the SCC exhibited superior adhesion to the o-concrete when hammering and sustained aggressively polishing by sandpapers. In addition, the intrinsic acid and base resistances (pH 1–13) of ODA and epoxy resin have ensured an environmentally stable SCC with an order of magnitude lower current density and 30% higher voltage potential to against corrosions. Furthermore, the SCC had a remarkable self-cleaning ability, and 68% and 87% antimicrobial reductions of Staphylococcus aureus and Escherichia coli bacteria, respectively. Therefore, this s-concrete coating prepared through facile and rapid two-step mixing processes has great potential to be implemented practically in the construction industry.