Surface modification of thin film composite polyamide membrane using atomic layer deposition method

We present surface modification of thin-film-composite (TFC) polyamide (PA) reverse osmosis (RO) membrane by atomic layer deposition (ALD) process using trimethylaluminium (AlMe3). The aim of the inorganic ALD coating is to improve the anti-fouling performance of TFC PA membranes. The ALD processing parameters were systematically studied because of the lack of previous investigations of the ALD coated RO membranes. Two different processing temperatures (70 °C and 100 °C) and three different ALD cycles (10, 50 and 100) were used to deposit the Al2O3 ALD coatings on TFC PA membranes. The ALD process parameters affected on the hydrophilicity and the surface polarity as well as on the surface roughness of the coated membranes. The bacteria attachment test results indicated that the lowest number of Pseudomonas aeruginosa cells was adhered on the most hydrophilic and polar surface, among the ALD coated membranes. RO tests showed the effect of ALD coating on the water and salt permeability as well as on the salt rejection of the membranes.