Modelling the sensor and actuator operations of the ElectroMechanical Film EMFi

The ElectroMechanical Film (EMFi) is a thin, cellular, biaxially oriented polypropylene film coated with metal electrodes. Elementary models with one air gap structure have been previously proposed to describe the EMFi's operation as a sensor and as an actuator. In this work a model based on a multiple air gap structure is presented and shown to reduce into a model with one air gap. The models are based on charge layers on the polypropylene/air interfaces and on the film's surfaces. The models are evaluated with some experimental results.