Micro/nano Carbon Materials and Their Reinforced Composites Xiaodong (Chris) Li University of Virginia XL3P@virginia.edu
Epoxy- SWCNT nanocomposites X. D. Li et al., Nanotechnology, 15 (2004) 1416-1423 X. D. Li et al., J Nanoscience and Nanotechnology, 7 (2007) 2309-2317
Elastic modulus (GPa) CNT has disappointed us in its composites 50 40 30 Upper boundary Lower boundary Experimental H-T model M-T model 20 10 0 0 2 4 6 SWCNT concentration (wt.%) X. D. Li et al., Nanotechnology, 15 (2004) 1416-1423 X. D. Li et al., J Nanoscience and Nanotechnology, 7 (2007) 2309-2317
Agarose-clay nanocomposite preparation Clay platelets (montmorillonite MMT) Length (Width): 60-800 nm Thickness: ~ 1 nm Properties Elastic modulus: 178 GPa Density: 2.83 g/cm 3 Advantages High elastic modulus, aspect ratio, surface to volume ratio X. D. Li et al., Nanotechnology, 16 (2005) 2020-2029
Ductility Nanoclay - brittleness in its composites 200 Stress (MPa) 150 100 50 0 0.25 0 0.05 0.1 0.15 0.2 Strain (mm/mm) 0% clay 30% clay 60% clay 80% clay 0.2 0.15 0.1 0.05 0 0 20 40 60 80 100 Clay concentration (wt. %) X. D. Li et al., Nanotechnology, 16 (2005) 2020-2029
Hydrogen passivation induced dispersion of CNTs Ultrasonication only Coupled HP and ultrasonication X. D. Li et al., Advanced Materials, 24 (2012) 881-885
Hydrogen passivation induced dispersion of CNTs X. D. Li et al., Advanced Materials, 24 (2012) 881-885
Hydrogen passivation induced dispersion of CNTs X. D. Li et al., Advanced Materials, 24 (2012) 881-885
Hydrogen passivation induced dispersion of CNTs X. D. Li et al., Advanced Materials, 24 (2012) 881-885
Hydrogen passivation induced dispersion of CNTs X. D. Li et al., Advanced Materials, 24 (2012) 881-885
Hydrogen passivation induced dispersion of graphene X. D. Li et al., Scientific Reports, 3 (2013) 2086
Hydrogen passivation induced dispersion of graphene X. D. Li et al., Scientific Reports, 3 (2013) 2086
Hydrogen passivation induced dispersion of graphene X. D. Li et al., Scientific Reports, 3 (2013) 2086
The Shell of red abalone Nanoscale structure A nacre aragonite plate consists of thousands of nanograins! These nanograins are cobble-like polygons of approximately 32 nm in diameter, and are densely packed to form individual plates. X. D. Li et al., Nano Letters, 4 (2004) 613-617
Interlocking mechanism In-situ tensile load-time curve and AFM images Interlocking Mechanisms Nanoasperities Aragonite platelet pull-out Nanoasperites imposing arrangement - Increasing sliding resistance and absorbing energy R.Z. Wang et al., J. Mater. Res., 16 (2001) 2485-2493.
How do nanonecklace fibers work in composites? X. D. Li et al., Advanced Materials, 20 (2008) 4091
Can we synthesize nanonecklace fibers? Nanonecklaces with SiO x beads in boron strings Formation mechanism of the nano/micro necklaces 50 mm X. D. Li et al., Applied Physics Letters, 89 (2006) 053108
Superior reinforcing effect from B/SiO x nanoneklaces 0.5 wt% nanonecklace reinforced epoxy nanocomposite Control sample Hardness: 0.21± 0.01 GPa Elastic modulus: 3.59 ± 0.07 Gpa 0.5 wt% B/SiO x Nanocomposite Hardness: 0.34± 0.05 GPa 32% increase Elastic modulus: 4.75 ± 0.39 Gpa 62% increase Better than CNT in terms of reinforcing effect! 1 wt% CNT Nanocomposite Hardness: 8% increase Elastic modulus: 12% increase X. D. Li et al., Advanced Materials, 20 (2008) 4091
TEM characterization of B/SiO x nanonecklaces X. D. Li et al., Advanced Materials, 20 (2008) 4091
Elastic modulus of boron nanowires C.-H. Lin, H. Ni, X. N. Wang, M. Chang, Y. J. Chao, J. R. Deka, X. D. Li, Small, 6 (2010) 927-931.
Convert a cotton T-shirt into a hybrid B 4 C/C composite X. D. Li. et al, Advanced Materials, 22 (2010) 2055 2059
Are B 4 C nanowires strong? X. D. Li. et al, Advanced Materials, 22 (2010) 2055 2059
New finding super-elasticity X. D. Li. et al, Advanced Materials, 22 (2010) 2055 2059
Outstanding UV irradiation blocking properties X. D. Li. et al, Advanced Materials, 22 (2010) 2055 2059
Superior mechanical reinforcing effect X. D. Li. et al, Advanced Materials, 22 (2010) 2055 2059
Bioinspired, multiscale reinforced composites X. D. Li et al., Nano Letters, (2018)
Bioinspired, multiscale reinforced composites X. D. Li et al., Nano Letters, (2018)
Bioinspired, multiscale reinforced composites X. D. Li et al., Nano Letters, (2018)
Bioinspired, multiscale reinforced composites X. D. Li et al., Nano Letters, (2018)
CNT/B 4 C composites X. D. Li et al., Advanced Engineering Materials, 16 (2014) 161-166
Summary - Coupled HP and ultrasonication effectively disperses CNTs and graphene. - Nanonecklaces are much better than CNTs in terms of reinforcing effect! - Micro/nano hybrid fillers are more powerful in reinforcing than nano filler alone. - There are still a lot to learn from nature.
Acknowledgments - National Science Foundation - NASA - Army Research Office - DOE - ACS Petroleum Research Fund