Microplastic fibres (MPFs) released during the laundering of synthetic textiles are one of the largest sources of microplastic pollution in oceanic environments, forming a barrier to a sustainable textile industry. Here we report a robust fabric finish for nylon, taking advantage of environmentally friendly polydimethylsiloxane (PDMS) brushes, which lessens the release of MPFs by lowering friction. Tribological evaluation reveals a substantially reduced coefficient of friction for PDMS-coated nylon in both dry and wet conditions. A molecular primer based on sulfonated mercaptosilane creates strong ionic bonding between the PDMS coating and the nylon fabric to enhance wash durability. Accordingly, MPF formation can be reduced by 93 +/- 2% for coated fabrics after repeated laundering. Importantly, none of the essential properties, such as hydrophobicity, surface structure and comfort of the fabrics, are compromised after washing. Low-friction fabric finishes provide a green route for the design of synthetic fabrics and could help the textile industry transition away from its current, unsustainable practices.