Wettability modification of graphene oxide by removal of carboxyl functional groups using non-thermal effects of microwave

We study the non-thermal effects of microwave on the wettability of graphene oxide. It is shown that removal of carboxyl compound by using the non-thermal microwave effects decrease the wettability of graphene oxide. X-ray photoelectron spectroscopy (C1s and O1s peaks) and Fourier transform infrared spectroscopy show that carboxyl compound decreases dramatically due to microwave irradiation while other functional groups were gradually reduced. Consequently, after 20 min microwave irradiation, carboxyl functional groups are removed. Wettability tests of carboxyl-reduced graphene oxide show that water uptake capability decreases to half and contact angle of water droplets increases from ~ 29.7° to ~ 69.9°. - Highlights: • Carboxyl compound is removed by using the non-thermal microwave effects after 20 min. • Water uptake capability decreases to half by removal of carboxyl functional groups. • Contact angle of water droplets increases from ~ 29.7° to ~ 69.9° in carboxyl-reduced graphene oxide