In order to improve the water permeability of poly(vinylidene fluoride) (PVDF) ultrafiltration (UF) membranes with low molecular weight cut-off (MWCO), polydopamine (PDA) was employed in the membrane preparation process. Owing to its merits of material-independent adhesion. PDA was coated on inorganic partides or added in coagulation bath to tailor the final membrane structure and property. The introduction of PDA broke through the permeability/selectivity trade-oltof the PVDF membrane. By adding the PDA coated titanium dioxide (PDA/TiO2) nanoparticles, water flux increased by 287% while MWCO kept similar with the pristine PVDF membrane. Thermodynamics and Kinetics of the PVDF/additives/non-solvent were analyzed and shown that nanoparticles reduced the thermodynamic stability and increased the phase separation speed, and the speed can be adjusted using different nanopartides. Additionally, X-ray diffraction (XRD) test indicated that PVDF crystalline form changed from alpha phase to beta phase after adding different nanoparticles. Permeability/selectivity trade-off was broken through by DA addition in coagulation bath. Compared with the original PVDF membrane, when the DA concentration of the coagulation bath was 2.0 g.L-1, water flux increased by 312%, and MWCO of the PVDF membrane ranged in 10,000 to 20,000 Da as well as contact angle decreased from 81.4 degrees to 45 degrees. (C) 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.