Modification of superhydrophobic surface on metal fins in heating, ventilation and air conditioning using PVDF/TiO2 coating
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Date
2019-06
Authors
Low, Ying Kai
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Abstract
Moisture condensation on the metal fins of HVAC is a serious issue as it will trap dust particles and reduce the energy efficiency of the system. In order to tackle the problem, the surface of the metal fins is modified. Artificial superhydrophobic surface with self-cleaning property is proposed to tackle the issue. The purpose of this work was to prepare and investigate the superhydrophobic coating on aluminium and copper fins. Dip-coating method was used to coat the coating solution on the metal surface. Screening of materials was carried out to find potential functional ingredient for coating. Polyvinylidene fluoride (PVDF) coating solution gave high hydrophobicity with high water contact angle (WCA) compared to steric acid and acrylic polymer solution. The PVDF was incorporated with TiO2 nanoparticles to prepare the coating solution. The effect of concentration of PVDF and TiO2 nanoparticles on the hydrophobicity was investigated. As concentration PVDF and TiO2 in the coating increased, the hydrophobicity of the surface increased. The optimum concentration of PVDF and TiO2 are 10.0 wt% and 1.0 wt% respectively which created smooth coated surface with high hydrophobicity (WCA from 137.3˚ to 138.2˚). Silane is used as primer to pre-treat the metal surface to improve the adhesion between the coating and metal surface. The Trimethoxymethylsilane (MTMS) and (3-glycidyloxypropyl)trimethoxysilane (GLYMO) were used in the study. However, incompatible concentration of silane gave weak bonding and unable to improve the adhesion.