Future of Engineering

A year of adding polymers to nanoparticles and testing their opacity left chemistry Ph.D. student Lindsay Bombalski frustrated. Although she was using a standard procedure to test the particles and characterize them by how much light they scatter, two samples were not giving her any signal at all, as though they had no opacity.“At no point did we think we were looking at something interesting,” said Michael Bockstaller, assistant professor of materials science and engineering who worked with Bombalski and chemistry professor Krzysztof Matyjaszewski on the project. As it turns out, they discovered that that “something” could be used to improve product packaging, windshields, and sunblock.

Particle additives such as polymers are often added to particles in other materials to increase heat resistance or mechanical strength of materials. However, the problem with this technique is that the reinforced particles scatter, altering the particles’ original appearance and making them virtually unusable for any matter that requires light to pass through.This scattering is caused by the change in the particles’ refractive index — an assessment of how fast light travels within a material — when the inorganic particles are added to an organic solution. The researchers found that by planning a target refractive index, they could eliminate the scattering of particles.

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Labels: Physics