Using contact angle measurement technique for determination of the surface free energy of B-SBA-15-x materials

Abstract

Pure and boron-containing, Santa Barbara Amorphous (SBA-15) mesoporous materials and B-SBA-15-x (x is molar ratio of Si/B = 50, 30, 10), were synthesized via a direct hydrothermal method. Samples were characterized by XRD, BJH pore size distribution and SEM techniques. A contact angle technique was used to determine surface free energy and its dispersive and polar components. For this purpose, ethylene glycol (EG), diiodomethane (DIM), formamide (FA) and water were used as model liquids to detect the contact angles. The OWRK/Fowkes approach was used to calculate the surface free energy values. Total surface free energy (gamma(S)) values of pure SBA-15 and B-SBA-15-50, B-SBA-15-30, B-SBA-15-10 were calculated as 64.365, 63.545, 63.490 and 64.218 mJ/m(2) at room temperature, respectively. The main results of the study can be summarized as follows: (i) The contact angle measurement technique is suitable for determining the total surface free energy (gamma(S)) and its dispersive and polar components (gamma(d)(S) and gamma(S)(p), respectively) of SBA-15 mesoporous materials and (ii) Addition of boron did not have a significant impact on the characteristic structure of SBA-15.