Simulation of the Acoustic Environment for the Manufacture of Graded Porosity Materials by Sonication

Many materials require functionally graded cellular microstructures whose porosity is engineered to meet specific requirements of diverse applications (e.g. polymers and/or ceramics that mimic biological material such as soft tissue and bone). It has been shown in previous work that the bubble growth rate of a polymeric foam can be influenced by the surrounding acoustic environment and, once solidified, produce a solid of graded porosity. Motivated by the desire to create a flexible process for engineering graded foams this work investigated how a COMSOLTM model was developed for assessing the acoustic environment that a foaming melt was subjected to. The COMSOLTM model has demonstrated good correspondence with the experimental results. The ability to predict the interactions of ultrasound with the polymeric materials undergoing foaming will allow this phenomenon to be exploited further in the manufacture of porous materials with engineered cell sizes and distributions.