Injection Molded Nanostructures Together with Hearing Instrument Materials

Abstract: The purpose of this Master's Thesis was to gain insight to how injection molded nanostructures could be used together with hearing instrument materials. The reason to investigate this new nanotechnology was to see if it is of interest for Oticon to invest in. To reach conclusions, literature was studied regarding surfaces wetting properties, capillary effects, adhesion and material properties. Surface properties of different polymers were determined by measuring contact angles and surface energies. Thereafter, two tools were designed in collaboration with Oticon and Transform in order to test how well Oticons hearing aid materials could replicate the nanostructures. The two test geometries were also created to test capillarity and glue adhesion. From the contact angle and surface energy measurements, plus the two test geometries, some conclusions were made. All materials could replicate the nano\-structured pattern, where the semi-crystalline polyamide gave the best results. From the glue adhesion test it could be seen that the nanostructured material with the highest surface energy, amorphous polyamide, gave best results. Further it was also possible to draw the conclusion that in capillaries a nanostructured surface, together with a chemical coating, is able to hinder water ingress to some extent. From the results of this project it is possible to further investigate whether this is an interesting technology for Oticon. Future studies could consist of studying wear of the tools and how nanostructures are replicated on curved geometries.