Microcapsules for immediate UV-light triggered release

 
Triggered release of active substances, from reservoirs activated by remote stimuli, is desired in a range of fields. Critical bottlenecks are cost-efficient formulation pathways applicable for industrial scale-up, viable triggers, and immediate release rather than continuous release upon activation. UV-sensitive microcapsules based on self-immolating polyphthalaldehyde, in combination with thin shells and morphological weak spots, are here shown great potential for immediate triggered release. A fluorescence microscopy method was developed to study the microcapsule morphology and the triggered release. Formation of the microcapsules is driven by the surface activity of the stabilizer, effectively lowering the high polymer-water interfacial tension, which is in sharp contrast to conventional encapsulation systems. The capsules are highly sensitive to both acid- and UV-mediated triggers, leading to a rupturing of the shell that releases the actives. In both aqueous and dry environment, the microcapsules lose their core content after less than one minute of UV light exposure.