Optimization of concentration and exposure time of polytetrafluoroethylene (PTFE) for the development of hydrophobic coating of drying chamber of spray dryer

Abstract

Modelling was applied using response surface methodology (RSM) and central composite rotatable design (CCRD) in order to establish the optimum conditions for applying PTFE on borosilicate glass to create a hydrophobic surface coating. Two experimental operating conditions of concentration and exposure time of polytetrafluoroethylene (PTFE) were optimized, obtaining high contact angle value, and showed high hydrophobic characteristics for PTFE-coated plate. Multiple linear regression analysis was implemented to develop a second-order polynomial model for the response. Results indicated that the most significant (p<0.05) factors influencing the contact angle value of the PTFE-coated plate were the main effect of concentration of PTFE. When the PTFE concentration increases, the plate’s contact angle also increases. The optimum conditions to maximize the value of contact angle (113.23°) for hydrophobic characteristics were a PTFE concentration of 9.17% and a PTFE exposure time of 6 minutes. The experimental results met what was predicted, indicating the model suitability for hydrophobic conditions optimization for the plate. This research indicated a good optimization of a PTFE solution in developing hydrophobic surface on a PTFE-coated plate.