This work focuses on making PVDF ultrafiltration (UF) membranes by the new innovative Combined Crystallisation and Diffusion (CCD) method. The combined crystallisation and diffusion (CCD) method is a membrane fabrication technique based on a unidirectional freezing approach to fabricate porous membranes. The CCD method offers much better process control and batch reproducibility compared to the traditional methods used in industry such as the non-solvent induced phase separation (NIPS) and the thermally induced phase separation (TIPS). The CCD membranes have also shown to have much better permeances than their commercial counterparts with similar rejections. This work carried out three main studies, with each focusing on controlling the permeation rate, rejection capability and surface hydrophilicity of the CCD membranes respectively. The innovative dual-layer casting approach applied to CCD membranes in this study allows one to independently control the tightness of the separation layer, and improve the porosity in the support layer, which allows one to further enhance the membrane permeances while still maintaining the separation pore sizes. With this technique, it was for the first time that PVDF membranes with pore sizes of ~30 nm had pure water permeances (PWPs) as high as ~2400 LMH.bar-1, which is almost 15 times higher than traditional NIPS membranes. With regards to influencing the membranes’ rejection properties, a simple blending approach using PMMA as the additive was discovered. This is a cost and energy-efficient alternative to reduce the pore size compared to other routes such as increasing the total polymer loading or the cooling duty. Increasing the blender proportion progressively reduced the mean flow pore sizes of the membranes to below 20 nm which is then capable of producing safe drinking water by rejecting most viruses by size exclusion. For improving the membrane surface hydrophilicity, polydopamine (PDA) modification was applied to the CCD UF membranes, and the results showed good permeance recovery post BSA fouling. In fact, the PWP of fouled membranes were still higher by almost 3.5 times than that of fresh (un-fouled) commercial membranes. This showcased the true potential of CCD membranes for real-life applications and its ability to be able to challenge the well-established industry standards.