Spectroscopic and imaging approaches for evaluation of properties of one-dimensional arrays of formulated polymeric materials fabricated in a combinatorial microextruder system

We report optical spectroscopic and imaging approaches for the high-throughput nondestructive characterization of formulated polymeric materials fabricated as one-dimensional (1D) polymeric arrays. These materials are fabricated as 1–2 mm diameter fibers or 5–12-mm-wide by 0.3–1-mm-thick films using a combinatorial system that includes a microextruder (total barrel volume of 4.5 cm³) and microfeeders. Because our microextruder approach for fabrication of formulated polymeric materials requires ∼200 times less material compared to traditional scale extruders, it provides previously unavailable opportunities for characterization of extruded materials without their pelletization. Property changes in polymeric formulations are induced along the length of the 1D arrays by several approaches that include (1) variation in composition of 1D array during polymer microextrusion, (2) variation in processing conditions during polymer microextrusion, and (3) variation in exposure conditions of a performance test for different spatial regions along the length of the array. Polymeric 1D arrays are analyzed either in-line or off-line. In-line analysis is performed using spectroscopic luminescence emission and reflected light modes. For off-line analysis, 1D fiber and film arrays are coiled as helices and flat coils, respectively. Automated measurements of coiled 1D arrays are performed using modular scanning and imaging systems. The scanning system is based on a portable spectrograph and is coupled to an X-Y translation stage to produce scans of 100 μm step size. The imaging system is operated in luminescence emission and reflected light modes. Our fabrication and analysis approaches significantly reduce the amount of material and energy needed and increase the speed of development of formulated polymeric- materials by using approaches for characterization of coiled 1D polymeric arrays.