Preventing algae adhesion using lubricant-modified polydimethylsiloxane/polythiourethane nanocomposite

To meet the need for an environmentally friendly fouling-release coating with high mechanical strength and good adhesion to substrates, a four-component nanocomposite was developed by a simple and industrially applicable blending approach. The nanocomposite consists of mechanically stable matrix polythiourethane (PTU), 1 wt% low surface free energy and rubber-like polydimethylsiloxane (PDMS), 1 wt% lubricant silicone oil, and 1 wt% tetrapodal shaped micro-nano ZnO (t-ZnO) filler particles, hereafter named PPZO. The rubber-like PDMS formed microdomains at the PTU/air interface, while silicone oil was distributed between the PDMS microdomains. The tensile strength of PPZO nanocomposite was approximately 63 MPa, two to four hundred times higher than the tensile strength of previously reported oil-modified coatings. The adhesion strength of PPZO to the substrate was 30 times higher than that of pure PDMS. After a five-month dynamic field test, the PPZO surface revealed much less biofouling than the references (AlMg3 and PTU), confirming its long-term biofouling control property. The attached algae on PPZO could easily and completely be removed by gentle brush cleaning. The good biofouling control property of PPZO can be attributed to the increased water repellency (signified by the increased water contact angle) and the surface slippage by silicone oil incorporation.