Additive Manufacturing and Architected
Materials: New Processes and Materials
Christopher M. Spadaccini
Center for Engineered Materials and Manufacturing
Engineering Directorate
Lawrence Livermore National Laboratory
Livermore, CA USA 94551
E-mail: spadaccini2@llnl.gov

Material properties are governed by the chemical composition and spatial arrangement ofconstituent elements at multiple length-scales. This fundamentally limits material properties
with respect to each other creating trade-offs when selecting materials for specific applications.
For example, strength and density are inherently linked so that, in general, the more dense thematerial, the stronger it is in bulk form. We are combining inverse design methods such as
topology optimization, with advanced additive micro- and nanomanufacturing techniques tocreate new material systems with previously unachievable property combinations – mechanicalmetamaterials. The performance of these materials is fundamentally controlled by geometryat multiple length-scales, from the nano- to the macroscale, rather than chemical composition
alone. We have demonstrated designer properties of these mechanical metamaterials inpolymers, metals, ceramics and combinations thereof. Properties include ultra-stiff lightweightmaterials [1], negative stiffness [2], and negative thermal expansion [3] to name a few, as well
as functional properties such electrical [4], optical [5], and even chemical responses. Recently,
we have also demonstrated metamaterials which respond to external stimuli; namely magneticfields [6].
We have primarily utilized our custom developed additive micro- and nano- additive
manufacturing techniques to create these structures and materials. These include projection
microstereolithography (PSL), direct ink writing (DIW), and electrophoretic deposition(EPD). I will also touch on new advanced concepts such as volumetric additive manufacturing(VAM) [7], computed axial lithography (CAL) [8], parallel two-photon polymerization, anddiode-based additive manufacturing (DiAM) [9] as well as new materials including graphene
aerogel [10] and nanoporous gold [11].
References:[1] Zheng, X., Lee, H., Weisgraber, T.H., Shusteff, M., DeOtte, J., Duoss, E., Kuntz, J., Biener,M.M., Ge, Q., Jackson, J., Kucheyev, S.O., Fang, N.X., and Spadaccini, C.M., “Ultralight,Ultrastiff Mechanical Metamaterials,” Science, 344, 1373, June 20, 2014.
[2] Duoss, E.B., Weisgraber, T.H., Hearon, M.K., Zhu, C., Small, IV, W., Metz, T.R.,
Vericella, J.J., Barth, H.D., Kuntz, J.D., Maxwell, R.S., Spadaccini, C.M., and Wilson, T.S.,“Three-dimensional Printing of Elastomeric, Cellular Architectures with Negative Stiffness,”
Advanced Functional Materials, vol. 24, no. 31, 4905, August 20, 2014.
[3] Wang, Q., Jackson, J.A., Ge, Q., Hopkins, J.B., Spadaccini, C.M., and Fang, N.X.,“Lightweight Mechanical Metamaterials with Tunable Negative Thermal Expansion,” PhysicalReview Letters, vol. 117, issue 17, October 21, 2016.
Lawrence Livermore National Laboratory is operated by Lawrence Livermore National Security, LLC, for the U.S. Department of Energy,
National Nuclear Security Administration under Contract DE-AC52-07NA27344.

[4] Yao, B., Chandrasekaran, S., Zhang, J., Xiao, W., Qian, F., Zhu, C., Duoss, E.B.,
Spadaccini, C.M., Worsley, M.A., and Li, Y., “Efficient 3D Printed Pseudocapacitive
Electrodes with Ultrahigh MnO2 Loading,” Joule, vol. 3, issue 2, February 20, 2019.
[5] Nguyen, D.T, Meyers, C., Yee, T.D., Dudukovic, N.A., Destino, J.F., Zhu, C., Duoss, E.B.,
Baumann, T.F., Suratwala, T., Smay, J.E., and Dylla‐Spears, R., “3D‐printed transparent
glass,” Advanced Materials, vol. 29, issue 26, July 2017.
[6] Jackson, J.A., Messner, M.C., Dudukovic, N.A., Smith, W.L., Bekker, L., Moran, B.,
Golobic, A.M. Pascall, A.J., Duoss, E.B., Loh, K.J., and Spadaccini, C.M., “Field Responsive
Mechanical Metamaterials,” Science Advances, vol. 4, issue 12, December 1, 2018.
[7] Shusteff, M., Browar, A.E.M., Kelly, B.E., Henriksson, J., Weisgraber, T.H., Panas, R.M.,
Fang, N.X., and Spadaccini, C.M., “One-step volumetric additive manufacturing of complex
polymer structures,” Science Advances, vol. 3, issue 12, December 8, 2017.
[8] Kelly, B.E., Bhattacharya, I., Heidari, H., Shusteff, M., Spadaccini, C.M., and Taylor, H.K.,“Volumetric Additive Manufacturing via Tomographic Reconstruction,” Science, vol. 363,
issue 6431, March 8, 2019.
[9] Matthews, M.J., Guss, G., Drachenberg, D.R., Demuth, J.A., Heebner, J.E., Duoss, E.B.,
Kuntz, J.D., and Spadaccini, C.M., “Diode-based additive manufacturing of metals using an
optically-addressable light valve,” Optics Express, vol. 25, issue 10, May 10, 2017.
[10] Zhu, C., Han, T.Y., Duoss, E.B., Golobic, A.M., Kuntz, J.D., Spadaccini, C.M. andWorsley, M.A., “Highly compressible 3D periodic graphene aerogel microlattices,” Nature
Communications, vol. 6, April 22, 2015.
[11] Zhu, C., Qi, Z., Beck, V.A., Luneau, M., Lattimer, J., Chen, W., Worsley, M.A., Ye, J.,
Duoss, E.B., Spadaccini, C.M., Friend, C.M., and Biener, J., “Towards Digitally Controlled
Catalyst Architectures: Hierarchical Nanoporous Gold via 3D Printing,” Science Advances,vol. 4, issue 8, August 1, 2018.

Lawrence Livermore National Laboratory is operated by Lawrence Livermore National Security, LLC, for the U.S. Department of Energy,
National Nuclear Security Administration under Contract DE-AC52-07NA27344.