Spatial and temporal evolution of the photoinitiation rate in thick polymer systems [electronic resource] /

by Kenning, Nicole Lynn.

It was once thought either impossible or inefficient to photopolymerize a thickness greater than a thin film because of the optical attenuation of light into the depth of the sample. However, if several considerations are allowed, it is indeed possible. Three particular modifications are essential to enhance light penetration into the depth of the system. An initiator that absorbs in a region of the spectrum where no other components absorb maximizes the incident light intensity for photolysis of the initiator. Concentration and/or molar absorptivity of the initiator lower than typically used in thin films enhance light penetration. Finally, photobleaching initiators exhibit decreased absorbance upon photolysis and thus allow light to penetrate more deeply into the system with time.