Alkyl chain modified diatomaceous earth superhydrophobic coatings

Abstract

Superhydrophobic surfaces were prepared with treated diatomaceous earth (DE) particles treated with different chain lengths at 2.2 mg/m2 silane treatment using alkyltrimethoxysilanes (H 3 C(CH 2 ) n−1 -Si(OCH 3 ) 3 with n = 3, 8, 12, 16, and 18). The properties of the untreated and treated DE particles were characterized with thermogravimetric analysis (TGA) and temperature modulated differential scanning calorimetry (TMDSC). The wettability and surface morphology of treated DE polyurethane coatings were studied using contact angle measurements and scanning electron microscopy (SEM). Surfaces with C12 and greater alkylsilane chain lengths could become superhydrophobic. Alkyl chain lengths shorter than C12 only formed hydrophobic coatings at 50% treated DE particle loading with polyurethane as a binder. SEM images showed an enhancement in surface roughness with increasing the chain length of treated DE.