Rice bran wax-hexane superhydrophobic coating production: an environmental assessment

Food packaging waste, particularly from plastic-based materials, represents an environmental concern, accounting for nearly half of global plastic waste. While bio-based superhydrophobic coatings have recently emerged as promising alternatives, their environmental implications remain insufficiently understood. This study applies a laboratory-scale cradle-to-gate life cycle assessment (LCA) to establish the environmental profile of rice bran wax-n-hexane superhydrophobic coating fabrication and identify the environmental hotspots within its production stage. The analysis is based on primary laboratory-scale production data, with a functional unit representing the preparation of the coating dispersion required for coating 1 m² of glass surface. Solvent selection was identified as the dominant contributor across all impact categories, accounting for at least 50% of the total impact, followed by electricity under the laboratory-scale modelling assumptions. Sensitivity analysis showed that substituting n-hexane with petroleum ether led to substantial reductions across all categories, with reductions exceeding 50% for eutrophication potential (64%), photochemical ozone creation potential (61%), abiotic depletion potential (elements) (53%), and terrestrial ecotoxicity potential (51%). Replacing the baseline electricity mix with renewable electricity further reduced impacts, with the most significant decrease observed in global warming potential (36%). Although petroleum ether resulted in slightly lower coating performance, it consistently achieved lower environmental impacts, highlighting the importance of integrating environmental assessment alongside functional performance during material selection. Overall, this study establishes an environmental baseline for an emerging bio-based superhydrophobic coating and demonstrates how early-stage LCA can identify fabrication hotspots and support environmentally informed process design for the development of more sustainable barrier coating technologies. Laboratory-scale LCA reveals solvent selection and associated upstream processes as the main environmental hotspots in coating dispersion preparation. Switching solvent systems and electricity supply significantly reduces environmental impacts.