Development of high durability hydrophobic coating using oil palm ash on glass substrates
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Date
2016-06
Authors
Luqmanul Hakim Ameran
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Abstract
Glasses are widely used in various field including building materials, construction, transport industry, solar panels and some other commercial products. However, the challenging issues are the stains that prone to occur on glass surface over a period of time. This is due to hydrophilic behavior of glass. Hence, the objective of this work are to form cost effective and environmental friendly hydrophobic coating (without fluoro compound) with water contact angle (WCA) more than 90o. In order to obtain cost effective coating, silicon sodium solution (SSS) was extracted from Oil Palm Ash (OPA) to substitute the use of Dimethyldiethoxysilane (DMDEOS) as modifier. The effect of temperature and time was varied during the extraction and it was found SSS obtained at 80oC for 2hours were suitable to be used to formulate hydrophobic coating. This solution contained high silica and the coating was more transparent in nature. The method of coating; wipe versus dip coating technique and number of coating layers were investigated and wipe coating technique and 3 layers coating resulted. Various ratio of SSS: DMDEOS were investigated to find best composition that poses high roughness and lowest surface energy for good hydrophobicity. The best composition was SSS: DMDEOS is 30:10 ratios which is SSS30D10. Characterization technique such as WCA, UV-Vis, FESEM, AFM and FTIR being studied. Among the composition studied, SSS30D10 which has composition between SSS and DMDEOS 30ml and 10ml respectively and showed good WCA of 100o due to low surface energy (23.37), high roughness (6.457nm) and good transparency with 96% transmission. This composition is then tested under accelerated environment; UV aging and water immersion for 240h. The WCA only drop by 4°, indicating the hydrophobic coating is very durable. Therefore, in this research, hydrophobic coating from OPA waste with formulation of SSS30D10 is recommended as best hydrophobic coating from cost and functional aspect.