3, Singapore Institute of Technology, Singapore, , Singapore
2, Institute of High Performance Computing, A*STAR, SIngapore, , Singapore
Controlling the fragrance release profile, especially the highly volatile top note, can prolong the desired scent of the fragrance. Here, a swollen cross-linked polyurethane acrylate (PUA) polymer is found to influence the evaporation rate of the fragrance molecule. Particularly, we found that the evaporation rate of benzyl acetate (BA), a typical top note, reduces by a factor of 8 (from 134 to 17 mg/m2/min) when BA is entrapped and released from the best-performing PUA polymer against a reservoir of BA. The average size opening of these free volumes in the fragrance-loaded PUA is ~6 nm, as determined by thermoporosimetry approach. Such pore size can effectively control the evaporation rate of BA as predicted by the theoretical model, which reveals that <16 nm pore diameter is required. Computational modeling shows that an optimal chain length for the modulator in sustained released of fragrance, confirming the experimental data. BA continues to be released from PUA matrix even after 3 months while the same amount of BA would have completely evaporated after 1 week. Such release performance, where ~50wt% of BA remains in the PUA matrix after 60 days, is one of the best performing techniques in sustaining the release of top note in literature. Lastly, we demonstrates that this material system can be 3D printed into customized membranes and shapes for controlled release of fragrance.