Effect of Etching and Modification on the Hydrophobic Angle of Epoxy/Poss Nanomaterials

Abstract

In this study, simple and feasible methods are used to increase the hydrophobicity of EP-POSS, that is, etching with concentrated hydrochloric acid and concentrated ammonia water, followed by modification with polytetrafluoroethylene and stearic acid. The principle of the study is to increase the hydrophobic angle of EP-POSS by immersion in concentrated hydrochloric acid and concentrated ammonia for a sufficiently long time, followed by modification with low-surface-energy materials, i.e., polytetrafluoroethylene and stearic acid. The contact angle of EP-POSS increased from 100° to 133° after immersing in 3 mol/L hydrochloric acid for 12 min. Compared to hydrochloric acid, the surface roughness and contact angel were not changed significantly by immersing in concentrated ammonia for 4 hours. The contact angle was not changed obviously after immersing in 0.1 mol/L polytetrafluoroethylene for 24 h, and only changed from 135° to 136° when immersed in 0.1 mol/L stearic acid. It shows that PTFE and stearic acid hasn?t effectively grafted to the surface of EP-POSS, and has no effect to the micro-nano structure of EP-POSS. According to the experimental results, hydrochloric acid etching is the proper way to enhance EP-POSS contact angel. According to further investigates, it can be determined that treating EP-POSS at 40 °C for 12 min with 3 mol/L hydrochloric acid can significantly improve its hydrophobicity, thus, the hydrophobic performance of EP-POSS is considerably improved.