Preparation of Hydrophobic Surface of Stearic Acid Encapsulated Calcium Carbonate

• Main Author: Muhammad Pohan, Rizaldy
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/40817
• Institution: Institut Teknologi Bandung

Hydrophobic surfaces are actively investigated due to their potential for various technological applications. Synthesis of hydrophobic surface here is aimed at attempting the usage of relatively cheap and non-toxic materials from the local market. Calcium carbonate powder and stearic acid are commonly available in the local market and a good candidate for developing hydrophobic surfaces. Calcium carbonate can enhance the surface roughness, while stearic acid reduces the surface energy. The development of hydrophobic surface was conducted by blending calcium carbonate powder into stearic acid solutions. Ethanol and hexane is used as a solvent to prepare stearic acid solution with various concentrations. 10 gram of calcium carbonate powder is poured into 25 mL stearic acid solution while stirring on a heated plate at 50°C for 30 minutes, followd by cooling and drying. The stearic acid encapsulated calcium carbonate powders was spread onto the surface of adhesive tape. Hydrophobic properties was characterized by observing the contact angle between a 5?L water droplet and the covered tape surface of stearic acid encapsulated calcium carbonate, and their stability against elapsed time. It is found that the maximum contact angle of 149° and 147° is achieved for the powder developed by using 2% weight stearic acid for hexane and ethanol, respectively. The stability of a water droplet on the hydrophobic surface lasted about 115 minutes, and the contact angle has decreased 30% after 2 hours of elapsed time. The usage of acrylic resin as a binder has reduced the contact angle due to the lack of surface roughness. Keywords: hydrophobic, calcium carbonate, stearic acid, acrylic resin, contact angle