(777g) PDMS-Based Ink Development for 3D Printing Applications

Additive manufacturing (AM) is an emerging research field due to its ability to manufacture materials with controlled geometry and properties using computer-based 3D printing technology.[1-2] Currently, the main challenge with this technology deals with limited materials, or ink, available for processing, specifically in the field of polymers. Only a single commercially available silicone resin (SE1700) possesses an appropriate viscosity and flow suitable for 3D printing capabilities, severely limiting advancements for improved performance of silicone-based materials for aerospace, engineering, and biomedical applications. Advancements in resin development rely on both new printable formulations and integration of novel fillers in order to alter the material’s properties. Typical fillers include fumed silica particles; however, other fillers (carbon nanotubes, graphene, surface-modified silica) can be incorporated to target specific applications relying on thermal, mechanical, and/or electronic properties.[3]

In this study, we first report novel 3D printable PDMS-based inks that possess appropriate rheological properties and wide temperature range applicability. Furthermore, compared to commercial silicone kits (e.g. SE1700), these inks also exhibit a very clear composition of ink formulation to broaden our application spectrum. Elastic architectures, which were patterned in a face-centered tetragonal (FCT) structure, were obtained by extrusion from a micro-nozzle using pressurized ink from a syringe, followed by a post-heat treatment to cure the part. The PDMS-based inks were prepared by mixing PDMS with three types of silica fillers having different surface characteristics to achieve three main attributes: i) sufficient elasticity (storage modulus) in the liquid state to withstand typical sagging and flowing issues during 3D printing; ii) excellent processing conditions and engineering properties for 3D printing applications, such as an appropriate pot life (working life or printable time), thermal properties over a wide temperature range (glass transition/crystallization), and a clear ink formulation of the 3D printed products; iii) full understanding of structure-property-performance relationship between silica fillers in the PDMS matrix and their 3D printed products, offering tunable properties to further extend their field of applications. [4]

 References

1. S. L. N. Ford, Additive Manufacturing Technology: Potential Implications for U.S. Manufacturing Competitiveness, J. Int. Commer. Econ. (2014)
2. Additive Manufacturing: Opportunities and Constraints: A Summary of a Roundtable Forum Held on 23 May 2013 Hosted by the Royal Academy of Engineering, Royal Academy of Engineering, (2013)
3. E. B. Duoss, T. H. Weisgraber, K. Hearon, C. Zhu, W. Small, T. R. Metz, J. J. Vericella, H. D. Barth, J. D. Kuntz, R. S. Maxwell, C. M. Spadaccini, T. S. Wilson, Adv. Funct. Mater. 24, 4905 (2014).
4. K.-S. Lee and A. Labouriau US Provisional Patent Application. (2017).