FAQ About (-COOH) Functionalized Single Walled Carbon Nanotubes

1) What does the 2.7% carboxyl content mean in practice?

A carboxyl content of 2.7% describes the proportion of –COOH groups introduced onto the nanotube surface. Those groups serve two purposes: they raise polarity so the nanotubes disperse in water and polar solvents with far less mechanical energy than unfunctionalized SWCNTs, and they provide reactive sites for covalent attachment of biomolecules, polymers and metal centres through standard carbodiimide coupling chemistry. Higher functionalization improves dispersibility but consumes more of the pristine sp² surface.

2) Should I choose the (-COOH) or the (-OH) functionalized grade?

Both grades share the same backbone specification — >92% purity, 1.0 nm average diameter, 370 m²/g SSA — and differ in surface chemistry and functionalization level. Choose –COOH at 2.7% when covalent conjugation is required, since carboxyl groups activate readily for amide coupling and coordinate metal ions. Choose the (-OH) functionalized SWCNT grade at 4.0% when hydrogen bonding into a polyol or polymer matrix matters more than covalent chemistry.

3) Does functionalization compromise electrical conductivity?

This grade is specified at an electrical conductivity of 98 S/cm with an Ig/Id ratio of 9. Covalent functionalization necessarily converts a fraction of sp² carbon to sp³ and introduces defect sites, so a functionalized nanotube does not match a pristine one on transport properties. An Ig/Id of 9 indicates that graphitic order remains dominant, which is why this grade retains useful conductivity for conductive composites, electrode formulations and transparent conductive films.

4) Which solvents are suitable for dispersing this grade?

The carboxyl surface makes this material suited to water and polar solvents, where it disperses uniformly and remains compatible with polar polymer matrices. Dispersion still requires energy input — typically bath or probe sonication with controlled power and duration — because van der Waals attraction between nanotubes remains strong. Excessive sonication shortens tubes and degrades the aspect ratio, so process energy should be optimised against dispersion quality rather than maximised.

5) Is >92% purity with 1.5 wt% ash suitable for electrochemical research?

For most electrochemical work, yes. The 1.5 wt% ash figure represents residual catalyst and inorganic content from CVD growth. Because trace metals can themselves be electrocatalytically active, studies making mechanistic claims about intrinsic carbon activity should account for that residue or run appropriate controls. For supercapacitor electrodes, battery conductive additives and fuel-cell supports, where performance rather than mechanistic attribution is measured, this specification is standard.

6) What do the dimensional specifications mean for composite reinforcement?

The tubes are specified at 1–2 nm outer diameter, 0.8–1.6 nm inner diameter and 5–25 µm length, giving an aspect ratio in the thousands. A high aspect ratio lowers the volume fraction needed to form a percolating conductive network, so target loadings are typically well below those required for particulate fillers. Preserving that aspect ratio through mixing and processing is usually the limiting factor on final composite performance.

7) What does an SSA of 370 m²/g indicate for this material?

370 m²/g reflects accessible surface on nanotubes that are individually separated rather than tightly bundled, and it sets the practical ceiling on interfacial area available for charge storage, catalyst dispersion or biomolecule loading. Single-walled nanotubes expose substantially more surface per gram than multi-walled grades, where inner walls contribute mass without accessible area — one reason SWCNTs are preferred where surface area governs performance, as discussed in SWCNT vs MWCNT.

8) In what quantities is this grade available?

This material is supplied in 5 g, 25 g, 100 g, 500 g and 1000 g quantities, with larger volumes quoted on request, supporting both single-project academic work and sustained industrial development. Alternative purities, lengths and functionalizations within the same product family are listed under single-walled carbon nanotubes.