Patents have been awarded and licenses have been negotiated, one to Dow Chemical, for a material created by a Cambridge University professor and researcher.

The material, microcapillary film (MCF), is a flat extrusion-processed, plastic film that is flexible and contains an array of microcapillaries that run its entire length. The capillaries are engineered at uniform distances, ranging between 30 microns and 1 millimeter in diameter depending on the die design and processing conditions.

MCF with varied voidage, die, and processing conditions. Image source: Cambridge UniversityCapillaries are formed in the material as air is sucked into molten plastic through hypodermic needles. Using numerical modeling, the team is able to understand how the operation can affect the final shape and form of the MCF. Computer codes are used to predict key product features. Additional development has allowed the product to achieve high voidage within the material. The team says the material is an excellent heat exchanger and development is underway to use it in solar water heating for an energy efficient, lightweight domestic heating system.

Dow has further advanced the development of MCF, applying for a patent for the film which allows for coextrusion of a second polymer into the microchannels. In a paper presented at a Society of Plastics Engineers’ ANTEC conference, a Dow researcher explained how different viscosities and processing conditions affect the microcapillary structure creating a variety of unique films.

The Cambridge team anticipates the material can be used in sensors, as a low-cost material for solar panels, and for the sailing and automotive racing industry. It could even be used to create colored materials that do not use chemical dyes.