QCM-D experiments were conducted using a Q-sense open module (401 E4 system, Q-sense, Sweden) with a gold-coated sensor to characterize the mass of the deposited TiO2 and GO during the LbL procedure. The sensor was spin-coated with a thin PSf layer to simulate the PSf base membrane subject to surface modification. The procedure for the QCM-D experiments was the same ad that for the membrane surface modification by TiO2-Go.
The vibration frequency and dissipation of the sensor were recorded during the coating process to calculate the amount of mass (ng/cm2) deposited on the sensor surface.