RAMAN CHEMICAL IMAGING - NONINVASIVE VISUALIZATION OF POLYMER BLEND ARCHITECTURE

A generally applicable methodology for routine, noninvasive chemical image characterization of materials is described. The methodology is based on Raman imaging microscopy employing a solid-state acoustooptic electronically tunable imaging spectrometer integrated within a laser-excited optical microscope. Multichannel charge-coupled device detection is employed to capture the Raman images. Chemical imaging with electronically tunable filters can be performed automatically under computer control, making analysis of unknowns routine. The Raman chemical imaging system is applied to the visualization of polypropylene/polyurethane blends. Raman chemical imaging is complementary to electron microscopy for polymer blend characterization; however, Raman imaging does not require as extensive sample preparation. Raman imaging provides images having molecular specificity at the spatial resolution of the optical microscope, without the use of dyes or stains: Chemical image contrast is provided by the intrinsic vibrational signature of the polymer constituents in the blend.