Design and processing of an elastomeric nanocomposite for biomedical pressure sensing applications

Abstract Taguchi Method is used to identify parameter effects and interactions to inform the design and processing of a carbon black (CB) and poly(styrene-isobutylene-styrene) (SIBS) nanocomposite. Potential uses include stick-to-skin pressure sensors and other applications for which targeted mechanical properties and pressure sensitivity derived from the tailorability of SIBS/CB are required. Specimens ranging from 10% to 20% CB content by weight were fabricated by high-shear mixing, ultrasonication, and solvent casting. The relationship between pressure-sensing capability and tensile strength of SIBS/CB nanocomposites is complex and dependent upon nanoparticle dispersion (represented by high-shear mixing time), CB content, and casting temperature. By using an L8 3-Factor 2-Level Taguchi orthogonal array and screening analysis, design and processing parameters to achieve targeted mechanical and electrical performance of SIBS/CB nanocomposites can be determined through a relatively small number of experiments. Main effects and interactions of the processing parameters were identified. Analysis indicates that mechanical strength is highly dependent on CB content and dispersion (mixing time), whereas pressure-dependent electrical resistance is highly dependent on CB content and casting temperature. The predictive models derived from these efforts will enable preliminary design of processing parameters for SIBS/CB nanocomposites to targeted, application-specific mechanical and pressure-sensing properties.