title: Toward 3D Printing of Medical Implants: Reduced Lateral Droplet Spreading of Silicone Rubber under Intense IR Curing.
abstract: The direct fabrication of silicone-rubber-based individually shaped active neural implants requires high-speed-curing systems in order to prevent extensive spreading of the viscous silicone rubber materials during vulcanization. Therefore, an infrared-laser-based test setup was developed to cure the silicone rubber materials rapidly and to evaluate the resulting spreading in relation to its initial viscosity, the absorbed infrared radiation, and the surface tensions of the fabrication bed's material. Different low-adhesion materials (polyimide, Parylene-C, polytetrafluoroethylene, and fluorinated ethylenepropylene) were used as bed materials to reduce the spreading of the silicone rubber materials by means of their well-known weak surface tensions. Further, O2-plasma treatment was performed on the bed materials to reduce the surface tensions. To calculate the absorbed radiation, the emittance of the laser was measured, and the absorptances of the materials were investigated with Fourier transform infrared spectroscopy in attenuated total reflection mode. A minimum silicone rubber spreading of 3.24% was achieved after 2 s curing time, indicating the potential usability of the presented high-speed-curing process for the direct fabrication of thermal-curing silicone rubbers.
authors.affiliation: Cluster of Excellence Hearing4all, 30625 Hannover, Germany.|BioMaterial Engineering, Department of Otorhinolaryngology, Hannover Medical School , Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Stieghorst
authors.affiliation: Cluster of Excellence Hearing4all, 30625 Hannover, Germany.|BioMaterial Engineering, Department of Otorhinolaryngology, Hannover Medical School , Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Majaura
authors.affiliation: Cluster of Excellence Hearing4all, 30625 Hannover, Germany.|BioMaterial Engineering, Department of Otorhinolaryngology, Hannover Medical School , Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
authors.forename: Hendrik
authors.initials: H
authors.lastname: Wevering
authors.affiliation: Cluster of Excellence Hearing4all, 30625 Hannover, Germany.|BioMaterial Engineering, Department of Otorhinolaryngology, Hannover Medical School , Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
authors.forename: Theodor
authors.initials: T
authors.lastname: Doll
mesh_terms: D007834:Lasers; D010100:Oxygen / Q000737:chemistry*; D058626:Plasma Gases / Q000737:chemistry*; D012826:Silicone Elastomers / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D058626:Plasma Gases; D012826:Silicone Elastomers; D010100:Oxygen
keywords: 3D printing; customized neural implants; individually tailored implants; silicone rubber printing; spreading