Nanometer positioning, parallel alignment, and placement of single anisotropic nanoparticles using hydrodynamic forces in cylindrical droplets.
Droplets of liquid drying on a surface with pinned contact area develop an internal hydrodynamic flow that carries entrained particles to the air-liquid-substrate interface. We use this phenomenon in cylindrical, micrometer-sized droplets of large aspect ratio (more than 1000:1) to align, position, and place individual anisotropic nanostructures such as single-walled carbon nanotubes (SWNT). More than 84% of SWNT are aligned in parallel within +/-5 degrees relative to the target axis of alignment. A potential flow model accurately describes and quantifies the statistical variation in the positioning of the nanostructures. We demonstrate for the first time the top-down parallel alignment and placement of individual (unbundled) nanotubes from solution electrically contacted across gold electrodes.
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Richa
R
Sharma
Chang Young
CY
Lee
Jong Hyun
JH
Choi
Kejia
K
Chen
Michael S
MS
Strano
D016880:Anisotropy; D003198:Computer Simulation; D003460:Crystallization / Q000379:methods*; D044085:Microfluidics / Q000379:methods*; D008846:Micromanipulation / Q000379:methods*; D008962:Models, Theoretical; D036103:Nanotechnology / Q000379:methods*; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013314:Stress, Mechanical
D037742:Nanotubes, Carbon