Desalination membranes by deposition of polyamide on polyvinylidene fluoride supports using the automated layer-by-layer technique

Thin-film composite (TFC) membranes with a polyamide (PA) active layer are the industry standard in desalination applications. The layer-by-layer (LbL) approach provides more precise control over the properties of this active PA layer. The automated spin-assisted LbL version of this approach then minimizes human error and improves repeatability. To improve durability of these membranes, more robust supports are desired, such as polyvinylidene fluoride (PVDF). The use of the LbL technique on this support requires an interlayer to enable the deposition onto the PVDF. In this case, levodopa was utilized to coat the PVDF prior to deposition of the PA layer. The membranes exhibited moderate permeability and higher selectivity for sodium chloride under typical brackish water conditions compared to commercially available NF membranes. This novel interlayer further expands on the automated spin assisted LbL approach, enabling deposition of PA onto a support.

Automated summary

Thin-film composite membranes with a polyamide active layer are widely used in desalination applications, with the layer-by-layer approach providing precise control over the properties of the active layer. The automated spin-assisted version of this method reduces human error and improves repeatability. By using polyvinylidene fluoride as a more robust support and utilizing levodopa as an interlayer prior to the deposition of the polyamide layer, the membranes show moderate permeability and higher selectivity for sodium chloride.