A substrate-independent isocyanate-modified polydimethylsiloxane coating harvesting mechanical durability, self-healing ability and low surface energy with anti-corrosion/biofouling potential

Abstract

Polydimethylsiloxane (PDMS)-derived materials have been used as functional coatings in a wide range of industrial and engineering applications owing to their appealing physical and chemical properties. However, most of them cannot harvest mechanical durability, self-healing ability and low surface energy due to the conventional chemical crosslinking method. Herein, a polymer coating featuring multifaceted functionalities is developed by facilely brush-coating isocyanate-modified PDMS (I-PDMS) on diverse substrates, in which the adjacent polymer chains are physically crosslinked by the hydrogen bonds between the urea motifs. The prepared coating can withstand 500 cycles of adhesive tape-peeling or 200 cycles of sandpaper abrasion without losing its hydrophobicity. Besides, the dynamic nature of the intermolecular hydrogen bonds leads to appreciable self-healing ability which can essentially extend the coating’s lifespan. Moreover, the I-PDMS coating possesses low surface energy, i.e., ∼ 13.1 mJ/m2 and ∼ 28.8 mJ/m2 when the PDMS Mw is ∼ 30000 and ∼ 3000, respectively. These appealing properties strongly depend on the PDMS Mw which could be attributed to the variation in mobility of the polymer chains and density of the intermolecular hydrogen bonds. Furthermore, it is found that this I-PDMS coating can effectively mitigate corrosion and biofouling on metal substrates, implying its great potential as a protective coating in practical engineering processes. Our work offers a promising approach to prepare multifunctional PDMS-based coatings with considerable application prospect.