Free volume determination of azobenzene-PMMA copolymer by a pulsed low-energy positron lifetime beam with in-situ UV illumination
The free volume properties of a poly(methyl methacrylate)-azobenzene copolymer were for the first time directly probed by use of a low-energy positron lifetime beam with in-situ excitation capabilities, showing that the free volume cavity size was not appreciably influenced by photoisomerization and thermal isomerization in the temperature range 34-180 degreesC. lsomerization is therefore suggeste
