Designing nanoporosity in a swollen polymer for the controlled release of a highly volatile fragrance

Abstract

Controlling the fragrance release profile, especially the highly volatile top note, can prolong the desired scent of the fragrance. Here, the porosity of a swollen cross‐linked polyurethane acrylate (PUA) polymer, which is tuned by the length of a modulator, can influence the evaporation rate of the top note. In particular, the evaporation rate of benzyl acetate (BA), a common top note, is reduced by a factor of 6.5 (from 134 to 17 mg m–2 min–1) when BA is released from the best‐performing PUA against a reservoir of BA. The average diameter of an opening in the fragrance‐loaded PUA is ~6 nm, as determined by the thermoporosimetry approach. Such a pore size can effectively control the evaporation rate of BA, as predicted by the theoretical model, which reveals that a pore diameter of <16 nm is required. Computational modelling reveals the optimal chain length for a modulator used for the sustained released of fragrance, confirming the experimental data. Finally, BA continues to be released from the PUA matrix for a prolonged period, even after 3 months, whereas the same quantity of BA would completely evaporate after 1 week in the absence of PUA matrix. Approximately 50wt% of BA remains after 60 days, making it one of the best techniques in sustaining the release of a top note.

Osmanthus fragrance polyurethane/silkfibroin‐based double‐shellmicrocapsules for aromatic leather with sustained release fragrance

“…However, silk fibroin capsules were fragile due to poor thermostability, which limited its practical applications 21–24 . Notably, the synthetic polyurethane with high mechanical strength, oxidation stability and heat resistance was used as the shell of capsules to ensure the high encapsulation efficiency and loading rate 25–27 . If two or more materials combined as the wall material of the microcapsules, it is potential to display the advantages of each material and increase the loading rate, thus realizing the versatile and tunable properties of microcapsules 28–30 .…”

“…[21][22][23][24] Notably, the synthetic polyurethane with high mechanical strength, oxidation stability and heat resistance was used as the shell of capsules to ensure the high encapsulation efficiency and loading rate. [25][26][27] If two or more materials combined as the wall material of the microcapsules, it is potential to display the advantages of each material and increase the loading rate, thus realizing the versatile and tunable properties of microcapsules. [28][29][30] Typically, using the mixture of silk fibroin and polyurethane would meet the demand for improving mechanical properties, thermostability and flexural resistance.…”

Controllable Fragrance Release Mediated by Spontaneous Hydrogen Bonding with POSS–Thiourea Derivatives

“…[8][9][10][11][12][13] For instance, the fragrance molecules are enclosed in polymeric materials that can release the fragrances upon the breakage or diffusion of shells. [14][15][16][17][18][19][20][21][22][23][24][25][26] In contrast to physical encapsulation, chemical approaches of profragrances have been developed by Herrmann and others, with chemically covalent binding of volatile molecules to the proper substrates duringthe formation ofprofragrance non-volatiles, 1,[27][28][29][30][31][32][33] wherein the volatile perfume molecules are chemically released with cleavage of a covalent bond or a weak interaction such as hydrogen bond.…”