Short Carbon Nanotubes

By Cheap Tubes, INC

Short carbon nanotubes are multi-walled carbon nanotubes (MWCNTs) that have been cut to lengths of 0.5-2 um through controlled air milling — significantly shorter than the 5-30 um of standard MWCNT grades. This reduction in length dramatically decreases entanglement between tubes, lowering the viscosity of MWCNT dispersions and enabling uniform dispersion without the aggressive sonication that can damage tube structure or shorten tube length unpredictably. Short CNTs retain all the electrical, thermal, and mechanical properties of standard MWCNTs at the individual tube level. Their advantage is entirely in processability: easier to disperse, less prone to aggregate formation, and loadable at higher concentrations in polymer matrices without gel formation. Short CNTs vs. Standard MWCNTs - Length: Short CNTs 0.5-2 um; Standard MWCNTs 5-30 um - Outer Diameter: Short CNTs 8-50 nm; Standard MWCNTs 8-50 nm - Dispersion Ease: Short CNTs Excellent — 5-10 min sonication; Standard MWCNTs Moderate — 30-60 min sonication - Aspect Ratio: Short CNTs 10-250; Standard MWCNTs 100-3000 - Percolation Threshold: Short CNTs 1-5 wt%; Standard MWCNTs 0.1-1 wt% - High-Loading Processing: Short CNTs Excellent (>5 wt% possible); Standard MWCNTs Difficult (>3 wt% causes gelling) The key tradeoff: shorter tubes are easier to process but require higher loading to achieve equivalent electrical percolation as longer tubes. For applications where processability is the primary constraint — high-viscosity polymer matrices, thin coatings, precision inkjet deposition — short CNTs offer decisive advantages. Applications of Short Carbon Nanotubes High-Loading Polymer Composites In injection-molded thermoplastic composites, short CNTs can be loaded at 5-15 wt% without the fiber breakage and viscosity issues that plague longer tubes. At these loadings, they significantly improve tensile strength, stiffness, and electrical conductivity of polyamide, polypropylene, and ABS parts. This is the dominant application for short CNTs in commercial production. Conductive Coatings and Inks Short CNTs disperse to near-individual-tube level in common solvents (NMP, DMF, IPA) with 5-10 minutes of bath sonication — versus 30-60 minutes for standard MWCNTs. This makes them ideal for formulating conductive inks, antistatic coatings, and conductive paints where smooth, aggregate-free films are required at 2-5 wt% CNT loading. Battery Electrode Slurries Short CNTs disperse readily in NMP (the standard electrode solvent) and distribute uniformly in electrode films, preventing conductivity dead zones that reduce capacity and rate capability. At 1-3 wt% loading in cathode slurries, short CNTs improve C-rate performance by 15-25% compared to carbon black alone, with no processing penalty. Fast-Cure and Short-Window Systems Fast-cure epoxy systems, reactive injection molding (RIM), and UV-cure coatings have processing windows too short for extended mixing of standard MWCNTs. Short CNTs disperse in 5-10 minutes of low-shear mixing — compatible with rapid manufacturing processes without sacrificing conductivity or mechanical reinforcement. Dispersion Protocol For aqueous systems: disperse at 0.5-2 mg/mL using 10 minutes of bath sonication with 0.1-1% surfactant (SDS, Triton X-100, or SDBS). For organic solvents (NMP, DMF): 5-15 minutes probe sonication at 20-30% amplitude, no surfactant needed. For polymer melt blending: feed dry short CNT powder directly to a twin-screw extruder alongside polymer pellets — no pre-dispersion required. Available Grades Cheap Tubes offers short carbon nanotubes in outer diameters from 8 nm to 50 nm, in both unfunctionalized and COOH/OH/NH2 functionalized grades. Functionalized short CNTs offer even better dispersibility and are preferred for biomedical, polar matrix composites, and aqueous systems. All grades available from 1g (research) to kilogram (production) quantities. Pricing starts at $10/g.