title: Approaching theoretical strength in glassy carbon nanolattices.
abstract: The strength of lightweight mechanical metamaterials, which aim to exploit material-strengthening size effects by their microscale lattice structure, has been limited by the resolution of three-dimensional lithography technologies and their restriction to mainly polymer resins. Here, we demonstrate that pyrolysis of polymeric microlattices can overcome these limitations and create ultra-strong glassy carbon nanolattices with single struts shorter than 1 μm and diameters as small as 200 nm. They represent the smallest lattice structures yet produced--achieved by an 80% shrinkage of the polymer during pyrolysis--and exhibit material strengths of up to 3 GPa, corresponding approximately to the theoretical strength of glassy carbon. The strength-to-density ratios of the nanolattices are six times higher than those of reported microlattices. With a honeycomb topology, effective strengths of 1.2 GPa at 0.6 g cm(-3) are achieved. Diamond is the only bulk material with a notably higher strength-to-density ratio.
authors.affiliation: Institute for Applied Materials, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Bauer
authors.affiliation: Institute for Applied Materials, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Schroer
authors.affiliation: Institute for Applied Materials, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Schwaiger
authors.affiliation: Institute for Applied Materials, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany.
authors.forename: O
authors.initials: O
authors.lastname: Kraft
references.citation: J Mech Behav Biomed Mater. 2008 Jan;1(1):76-85
references.pmid: 19627773
references.citation: Nat Mater. 2013 Oct;12 (10 ):893-8
references.pmid: 23995324
references.citation: Adv Mater. 2010 Mar 12;22(10):1084-101
references.pmid: 20401933
references.citation: Science. 2014 Sep 12;345(6202):1322-6
references.pmid: 25214624
references.citation: Nanoscale Res Lett. 2013 Nov 20;8(1):492
references.pmid: 24256942
references.citation: Chem Rev. 2010 Jan;110(1):111-31
references.pmid: 19947596
references.citation: Science. 2009 Sep 18;325(5947):1513-5
references.pmid: 19696310
references.citation: Science. 2011 Nov 18;334(6058):962-5
references.pmid: 22096194
references.citation: Rev Sci Instrum. 2012 Dec;83(12):125001
references.pmid: 23278017
references.citation: Nano Lett. 2012 Aug 8;12(8):4392-6
references.pmid: 22783965
references.citation: Small. 2009 Dec;5(24):2792-6
references.pmid: 19823996
references.citation: Proc Natl Acad Sci U S A. 2014 Feb 18;111(7):2453-8
references.pmid: 24550268
references.citation: Philos Trans A Math Phys Eng Sci. 2006 Jan 15;364(1838):31-68
references.pmid: 18272452
references.citation: Adv Mater. 2012 May 22;24(20):2710-4
references.pmid: 22495906
references.citation: Nanoscale Res Lett. 2009 Sep 23;5(1):14-19
references.pmid: 20652145
references.citation: Science. 2014 Jun 20;344(6190):1373-7
references.pmid: 24948733
references.citation: Proc Natl Acad Sci U S A. 2003 May 13;100(10):5597-600
references.pmid: 12732735
references.citation: Adv Mater. 2012 Sep 18;24(36):4782-810
references.pmid: 22899377