Characterizing phase-separated microstructure of polymeric blended membrane using combined multiphoton and reflected confocal imaging

In this study, we propose a novel, minimally-invasive multimodal optical imaging method which combines multiphoton and reflected confocal microscopy for characterizing three-dimensional phase-separated microstructure of polymeric nylon/chitosan blends. The multimodal image acquisition was performed on a Zeiss LSM 510 inverted microscope system using a ti-sapphire laser source. Differences in nonlinear optical signals between individual homopolymers were used to characterize the phase-separation phenomenon within the polymeric blends. We also used the reflected confocal signals for defining the interfacial boundaries of different refractive indices. Our work demonstrates that the proposed multimodal imaging modality can be used to provide the necessary microstructural information for characterizing the degrees of phase separation within polymeric blends.