Microcapsules developed to deliver chemicals ‘on demand'

A research project at the College of Chemistry, University of California-Berkeley, developed the concept using microcapsules found in carbon-free copy paper.

The copy paper was developed to burst the capsules under the pressure of a pen, which helped the research group develop microcapsules that can be triggered once they are exposed to light.

Light-rupturable microencapsules​

The scientists say that light-rupturable, liquid-filled microencapsules were developed using coencapsulation of carbon nanotubes, based on an interfacial polymerization technique that forms a nylon external barrier to encase the capsule.

The nylon barrier takes the form of a sphere, which is about the size of a grain of sand, and designed to enclose any liquid chemicals using the coencapsulation carbon nanotubes.

The nanotubes have been developed to react to light from a laser, in turn converting it to heat that bursts the nylon capsule, allowing the contents to be dispersed when needed.

Impermeable shell walls​

Further to this, the scientists say that the microencapsules can be developed with impermeable shell walls, enabling the coexistence of otherwise incompatible chemicals in a single container, which can then be combined once the desired release is triggered.

Clearly the research work could have applications for personal care products such as anti-ageing creams, which are developed using high-technology active ingredients that are far more effective if they are locked in to a time-release microencapsulation process.

The scientists say that extensive testing of the encapsulation process showed that the barriers were extremely efficient and hardly showed any sign of leaking before the phototriggering was activated.

Release triggered using lasers​

Likewise, the scientists said that triggering release process using a laser was the equivalent of an ‘on-off’ switch, making the whole process very easy to control, both efficiently and quickly.

The research into the release mechanism is ongoing but the study underlines that it could have significant implications for both the personal care and home care industries, as well as for the development of pharmaceuticals and medicines.

The research team was led by Jean Frechet PhD and the most up-to-date results of the study appear in the peer-reviewed Journal of The American Chemical Society.