| Ionic Polymer Transducers (IPTs) display a sensing behavior, whereby a current signal is generated, when they are deformed. IPTs also exhibit bending deformation when a voltage difference is applied across the surfaces of the transducer, thus displaying actuation. However, the mechanisms responsible for actuation and sensing differ; research to date has focused predominantly on actuation, while identification of the fundamental physical mechanism responsible for IPT sensing remains an open topic. Nevertheless, IPTs are promising in sensing, reliable, flexible, light, and cost effective. Even so, they are poorly understood, which has limited their optimization and subsequently their widespread application. As sensors they are most often studied in bending mode; however a measurable signal can be generated in any mode of mechanical deformation. This thesis offers the streaming potential hypothesis as the mechanistic model explaining IPT sensing on the basis that it is uniquely able to predict the existence of a transient sensing signal in any mode of deformation. To date, streaming potential models of IPT transient sensing response under bending and shear have been presented. These models, however, have lacked access to appropriate transient experimental studies for validation; moreover, there has been a complete absence of study of the final compressive sensing mode. This thesis offers a modeling methodology appropriate to compression, while also offering experimental studies enabling validation studies for all IPT sensing modes. The experimental studies introduce novel test rigs enabling step-deflection application in bending, shear, compression modes and in situ measurement of the resulting transient IPT current. Finally, because the ultimate goal of defining the physical mechanism primarily responsible for sensing is to enable widespread use of these transducers, electrode architecture studies are offered as illustration of the potential to optimize IPT sensing via the streaming potential hypothesis. |
