Fragrance carriers
A novel thermally controlled release system was developed from PEO-b-PCL block copolymer compounds for fragrances or volatile compounds with extremely effective loading on the basis of multi-shell vesicles (MLV) while minimizing costs. Due to the high biocompatibility and biodegradability of PEO-b-PCL polymers, they do not contribute to the accumulation of microplastics in the environment. The large inner surface of the nanostructured, aqueous emulsion multi-shell vesicles of 500 nm size gives them high capacity for the absorption of fragrance molecules of different structure and high affinity to the textile.
The silica core shell nanoparticles newly developed at DWI from physiologically and ecologically harmless starting materials were added to the project. Both carrier systems can be used in aqueous formulations as well as in dry state on textiles/corporate identity clothing. The size distribution and the inner lamellar structure of the particles were investigated by cryoelectron microscopy (Kryo-EM). The evidence for the actual loading of the vesicles with a multicomponent fragrance oil, the high loading capacity and efficiency as well as the delayed or by a specific trigger caused continuous fragrance release in small concentrations were provided by gas chromatography mass spectrometry (GC-MS) and head space GC-MS. Multi-shell vesicles as well as silica particles are characterized by the desired high encapsulation efficiency for guest molecules of almost 100%. An outstandingly high capacity is obtained for the multi-shell vesicles, which allow the loading of a very high amount of fragrance in a very small amount of polymer. The goal of triggering a delayed release of fragrance in small concentrations or a release initiated by a specific impulse temperature at high loading efficiency with fragrances was achieved for both the multi-shell vesicles and the silica nanoparticles. By incorporating the fragrance oil into the fragrance carriers, the usual rapid development of fragrance notes for the top note, but especially for the heart and base note, could be considerably delayed: The top note was still detectable after 2 days for MLV, the heart note of the medium volatile fragrances after 9 days and the volatile fragrances such as 10-undecenal and 2-methylundecanal even after 30 days.