Nanomaterials @ Interfaces Research Group

We show that visible light can polymerize diacetylene monomers into polydiacetylene (PDA) in a two-photon process. We monitor the process by measuring Raman intensities of PDA using a Raman laser at 633 nm with variable intensity I and show that the Raman cross section at short times increases as I³, corresponding to a two-photon process. The process generates a relatively stable blue phase PDA, in contrast with UV polymerization that leads to a fast blue to red phase transformation.