Light transmission in nanocellular polymers: Are semi-transparent cellular polymers possible?

[Display omitted] •Optical properties of nanocellular polymers have been tested.•For microcellular foams as the mean pore is reduced the transmissivity decreases.•For nanocellular polymers a reduction of the cell size increases the transmissivity.•Semi-transparent cellular polymers could be produced reducing further the cell size. This work presents the light transmission through a collection of solid cellular polymers based on poly (methyl methacrylate) (PMMA) with cells sizes covering the micro and nano-scale. The obtained results showed that the behavior of light transmission when cell size is in the nano-scale is opposite to the one shown by microcellular foams or the one predicted by theoretical models of light scattering (LS). In fact, the expected trend is that a reduction of cell size increases the opacity of the samples. However, for nanocellular polymers based on amorphous polymers reducing the cell size increases the light transmission. Therefore, this result indicates that a further reduction of the cell size could result in cellular polymers optically semi-transparent.