Surface-controlled vapor transport in self-stratified GelMA/AESO coatings: From processing-driven morphology to moisture barrier performance

چکیده مقاله

Controlling vapor transport in polymer coatings through morphology rather than composition offers a scalable strategy for barrier optimization; however, the quantitative relationship between self-stratified structure and moisture transmission remains insufficiently elucidated. Here, light-curable GelMA/AESO coatings were employed as a model system to systematically investigate how processing-induced self-stratification governs water vapor transmission rate (WVTR) without altering overall formulation. Distinct stratified morphologies were generated by tuning curing parameters while maintaining identical bulk composition. WVTR was quantified using both instrumental and cup methods over a range of temperatures, revealing that surface GelMA enrichment significantly increases vapor transport, whereas formation of a continuous AESO-rich layer suppresses transmission. Reversal of exposure side further demonstrated that vapor transport is dictated primarily by surface composition and layer sequence, consistent with a surface-controlled sorption-diffusion mechanism. Long-term apple preservation and steam exposure tests validated the quantitative permeability trends and demonstrated simultaneous vapor transmission and liquid resistance. The optimized self-stratified coating achieved substantial reduction in WVTR relative to neat GelMA while maintaining breathable characteristics. Overall, the results establish morphology-directed vapor transport control as an effective approach for designing bio-based coatings with tunable moisture management properties.