Paper Number
AM17 

Session
Additive Manufacturing

Title
Multimaterial 3D printing of silica-titania glass: Predictive tuning of suspension rheology

Presentation Date and Time
October 16, 2018 (Tuesday) 11:05

Track / Room
Track 3 / Bellaire

Authors (Click on name to view author profile)

  1. Dudukovic, Nikola (Lawrence Livermore National Laboratory)
  2. Wong, Lana (Lawrence Livermore National Laboratory)
  3. Nguyen, Du (Lawrence Livermore National Laboratory)
  4. Destino, Joel (Creighton University)
  5. Yee, Timothy (Lawrence Livermore National Laboratory)
  6. Ryerson, Frederick (Lawrence Livermore National Laboratory)
  7. Suratwala, Tayyab (Lawrence Livermore National Laboratory)
  8. Duoss, Eric (Lawrence Livermore National Laboratory)
  9. Dylla-Spears, Rebecca (Lawrence Livermore National Laboratory)

Author and Affiliation Lines (in printed abstract book)
Nikola Dudukovic1, Lana Wong1, Du Nguyen1, Joel Destino2, Timothy Yee1, Frederick Ryerson1, Tayyab Suratwala1, Eric Duoss1, and Rebecca Dylla-Spears1
1Lawrence Livermore National Laboratory, Livermore, CA; 2Creighton University, Omaha, NE

Speaker / Presenter 
Dudukovic, Nikola

Text of Abstract
The ability to 3D print transparent glass could impact applications ranging from microfluidics to optics. Multimaterial printing offers incorporating diverse functionalities by spatial control of material composition. The addition of dopants such as titania to silica glass can impart modifications in the optical or mechanical properties of the material. In this regard, multimaterial additive manufacturing (AM) of glass could enable advanced optics with tailored properties. However, a lack of predictive methodology is frequently a bottleneck in material development for AM. Hence, exploration of new printable materials often relies on trial and error, which is time-consuming, labor-intensive, and costly. We overcome these issues by quantifying and controlling the rheology of colloidal suspensions for direct ink writing (DIW) of silica-titania glass. We formulate inks from suspensions of fumed silica in an organic solvent with a dissolved molecular titania precursor. The multimaterial construct is printed from two inks (doped and undoped), then heat treated to form a dense, transparent glass. Since this process is extremely sensitive to ink formulation and discrepancies in solids loading, it is challenging to control the printability and compatibility of these inks. We use a small set of experimental data and estimates of interaction potentials to develop a predictive tool that allows us to design and obtain compatible inks without additional chemical species. Using this approach, we can formulate inks that are well-matched both in desired rheological properties as well as total solids loading. We validate the model predictions and find that the rheology can be tuned for given process parameters. We print a multimaterial object from these inks to produce a transparent glass with spatial change in refractive index. ***This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 within the LDRD program 16-SI-003. LLNL-ABS-751466.***