Multiphysic modelling of a microactuator based on the decomposition of an energetic material: application to microfluidics

We present the conception of a micro pressure source for microfluidics applications. It consists in 3 main parts: (i) a heating resistance built on a dielectric membrane, (ii) an energetic material which decomposes generating a high volume of biocompatible gas, (iii) an elastomer membrane with high elastic properties. PDMS is chosen as the membrane material for its elastic properties. A bimetallic energetic material composed of Mn and Co is chosen because of the high amount of biocompatible gas liberated from its decomposition. When the actuation is required, the energetic material is heated beyond the ignition temperature to generate a high concentration of gas; the gain in pressure produces the deformation of the elastic membrane. Individual models have been developed for each physical phenomenon: (i) the heating of the resistance by an electro-thermal model, (ii) the gas generation from the decomposition of the energetic material based on an ideal gas model and a mass transfer model and coupled with the elastic membrane deformation with a mechanical deformation model. This paper presents each individual model under COMSOL Multiphysics that has been correlated with experimental results. Then, the implementation of all models into one global model allow us to predict the actuator performance as a function of input electrical signal.