Fabrication of self-assembled hydrophobic fluorinated silica particulate film

• Published in: Journal of fluorine chemistry Vol. 218; pp. 27 - 35
• Main Authors: Guo, Yudi, Zhao, Erqing, Guo, Xiaowei, Tang, Dongyan
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01-02-2019; Elsevier BV
• Subjects: Chemical composition; Contact angle; Fabrication; Fluorination; Fluoroacrylate film; Hydrophobicity; Langmuir-Blodgett films; Organic chemistry; Particulates; Self-assembling; Self-assembly; Silica; Silicon dioxide; Wetting; XPS analysis; Fluoroacrylate film; Hydrophobicity; Self-assembling; XPS analysis
• ISSN: 0022-1139; 1873-3328
• DOI: 10.1016/j.jfluchem.2018.11.013

Hydrophobic fluorinated cross-linked network films were prepared by self-assembling random fluoroacrylate polyol polymer on the HDI modified LB-SiO2 particulate monolayers. Surface analyses show a low surface segregation degree of fluorinated groups.
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•The ester groups stretch towards the inner surface during film forming process.•The surface enrichment of fluorinated groups bonded to ester groups is difficult.•The surface hydrophobicity is attributed to the polymer main chain of -C-C-.
Hydrophobic fluorinated particulate films were fabricated by coupling Langmuir-Blodgett silica (LB-SiO2) particulate monolayers with fluoroacrylate polymer, and the depth distributions of chemical compositions were studied. The resultant fluorinated particulate films show surface hydrophobic property with water contact angles (WCA) of 123° (300 nm) and 125° (550 nm), which is dominated in Wenzel wetting state. The surface F/C ratio is only 0.09 at 20°, which is slightly higher than 0.07 at 60°. Fitting results of C1s and O1s high-resolution spectra at 20° and 60° indicate the outmost surface is mainly occupied by fluoroacrylate polymer main chains and the ester side chains stretch toward inner surface and thus hydrophobic fluorinated groups in self-assembled fluoroacrylate film cannot efficiently segregate to the outer surface, which results in low surface F/C ratio and surface WCA.