If you're shopping for multi-walled carbon nanotubes for the first time, the catalog can be confusing. Three different MWCNT product lines, prices that span an order of magnitude, purity numbers ranging from 90% to 99.5%+, and a half-dozen diameter SKUs in each line. The right answer depends entirely on what you're doing with the material. Using research-grade MWCNT for a percolation network in a polymer composite is overspending. Using industrial-grade MWCNT for a fuel cell electrocatalyst support is undershooting and your results will scatter. This guide walks through how to make the right call by application, with a side-by-side comparison and specific recommendations for the use cases we see most often.
The Quick Answer
If your application is…
- Polymer composites, EMI shielding, conductive coatings, cement reinforcement, antistatic films, electrode percolation networks → Industrial Grade MWCNT (90%). Purity isn't the limiting factor; you're buying for mechanical and electrical percolation. Spending more for higher purity here is wasted money.
- General academic research, ink formulations, fiber spinning, hybrid material development, sensor substrates, supercapacitor electrode prep → Standard MWCNT (98%). The workhorse line. Reproducible, research-grade, and the right purity tier for most published-paper work.
- Heterogeneous catalysis, biomedical applications, single-tube electronic devices, fuel cell electrocatalyst supports, hydrogen storage, defined-surface-chemistry sensors → Graphitized MWCNT (99.5%+). When residual catalyst metals or amorphous carbon would compromise your results, the graphitization post-treatment eliminates both. The premium is worth it for these use cases.
Side-by-Side Comparison
| Spec | Industrial Grade | Standard MWCNT | Graphitized MWCNT |
|---|---|---|---|
| Purity | 90% | 98% | 99.5%+ |
| Post-treatment | As-synthesized (CVD) | Purified to research grade | Thermal graphitization (removes catalysts, converts amorphous carbon to graphitic structure) |
| Diameter SKUs | 10 nm, 10-30 nm, 20-40 nm | 8 nm, 8-15 nm, 10-20 nm, 20 nm, 20-30 nm, 30-50 nm, 50 nm | 8-15 nm, 10-20 nm, 20-30 nm, 30-50 nm, 50 nm |
| Functionalization options | Pristine (all diameters above) + COOH (10-30, 20-40 nm) + OH (10-30, 20-40 nm) | Pristine (all 7 diameters above) + COOH (8/8-15/10-20/20/20-30/30-50/50 nm) + OH (8/8-15/10-20/20-30/30-50/50 nm) + NH2 (20 nm) + Short COOH + Short OH variants | Pristine Graphitized (all 5 diameters above) + COOH-Graphitized (5 SKUs, 8-15 to 50 nm) + OH-Graphitized (5 SKUs, 8-15 to 50 nm) |
| Catalyst residues | Present (~10%) — Mo, Co, Fe typical | Reduced (~2%) | Largely eliminated (<0.5%) |
| Amorphous carbon | Present | Reduced | Converted to graphitic structure |
| Raman ID/IG (typical) | Higher (more defects) | Mid-range | Lowest (most graphitic) |
| Price tier | $ (lowest) | $$ (mid) | $$$ (premium) |
| Best for | Cost-sensitive composite + percolation work | General research, papers, broad applications | Catalysis, biomedical, high-purity electronics |
Industrial Grade MWCNT — When to Use, When Not To
The Industrial Grade MWCNT line (90% purity) is the cost-effective tier. CVD-synthesized, minimally post-processed, available in 10 nm singular, 10-30 nm combined-range, and 20-40 nm diameter SKUs. The ~10% non-tube content is mostly residual catalyst metals (Mo, Co, Fe) from the CVD growth, plus some amorphous carbon and nano-capsule byproducts.
Use it for:
- Polymer composite mechanical reinforcement (epoxy, PA66, PEEK, polyurethane)
- Conductive coatings and inks where percolation, not purity, drives performance
- EMI shielding films and ESD-protection coatings
- Cement and concrete nanocomposite reinforcement
- Antistatic textile coatings and yarn modification
- Battery electrode binder + conductive additive at scale
- Printable flexible electronics where cost per square meter dominates the engineering decision
- Educational lab work where students need bulk material to practice handling
Don't use it for:
- Heterogeneous catalysis (residual Mo, Co, Fe will compete with engineered active sites)
- Biomedical applications where metal cytotoxicity matters
- Single-tube electronic device fabrication
- High-purity sensor electrodes with defined surface chemistry requirements
- Fuel cell electrocatalyst supports
- Published-research surface-chemistry work (you'll get scattered results)
The decision rule: if the impurity load doesn't affect what you're measuring or what your product does, use industrial grade and save the cost premium for materials that actually matter to your performance.
Standard MWCNT — The Research-Grade Workhorse
The Standard MWCNT line (98% purity) is the broadest catalog by diameter range and the most commonly cited in peer-reviewed papers. Available in 8 nm, 8-15 nm, 10-20 nm, 20 nm, 20-30 nm, 30-50 nm, and 50 nm SKUs. Catalyst residues reduced to ~2%, amorphous-carbon content significantly lower than industrial grade, and reproducibility between lots good enough that controlled experiments produce clean results.
Use it for:
- Academic research where reproducibility and clean characterization data matter
- Ink and dispersion formulations for printable electronics and inkjet work
- Carbon nanofiber spinning + electrospinning with PAN or other polymer precursors
- Hybrid composite material development (MWCNT/GO, MWCNT/polymer/metal hydride)
- Sensor substrate fabrication where surface chemistry is engineered post-purchase
- Supercapacitor electrode preparation at research scale
- Pre-functionalized COOH, OH, or NH2 work (broadest pre-functionalized catalog of any MWCNT line)
- Any application where the published-paper community uses “MWCNTs” without further spec
Don't use it for:
- Pure cost-driven bulk composite applications (industrial grade is fine and cheaper)
- Catalysis where even 2% catalyst residue would skew your active-site measurements
- Biomedical applications where graphitized purity is the safety bar
The decision rule: if you're publishing research, characterizing reproducibility, or doing controlled experiments where impurities would scatter results, Standard MWCNT is the right starting point.
Graphitized MWCNT — The Premium Tier
The Graphitized MWCNT line (99.5%+ purity) takes Standard MWCNT material and applies a high-temperature thermal treatment that vaporizes residual catalyst metals and converts amorphous carbon to graphitic structure. The result is a MWCNT with the lowest Raman ID/IG ratio in the catalog, minimal metal contamination, and the most ordered crystalline structure available off-the-shelf. Available in matched 8-15 nm, 10-20 nm, 20-30 nm, 30-50 nm, and 50 nm SKUs, plus pre-functionalized COOH and OH variants.
Use it for:
- Heterogeneous catalysis where catalyst-metal residues would compete with engineered active sites (Pt, Pd, Au, transition-metal oxide supports)
- Fuel cell electrocatalyst supports (PEMFC, DMFC, AEMFC)
- Hydrogen storage composites where catalyst residues bias kinetics measurements
- Biomedical and biosensor applications where Mo/Co/Fe cytotoxicity matters
- Single-tube electronic devices where impurities create charge traps
- High-purity sensor electrodes with defined surface chemistry
- Photovoltaic and photoelectrochemical electrodes (clean charge transport)
- Aerospace and defense applications with stringent contamination specifications
Don't use it for:
- Anything where Standard MWCNT would have worked (you're overspending without performance gain)
- Bulk composite filler applications (waste of premium material)
The decision rule: if your application specifically requires the absence of catalyst residues or amorphous carbon (catalysis, biomedical, high-purity electronics), Graphitized MWCNT is the right choice and the cost premium is functional. Otherwise, you're paying for performance you can't use.
Two Special Cases Worth Calling Out
DIY purification of Industrial Grade or Standard MWCNT
If you want higher purity than your starting tier but don't want to pay the Graphitized premium, you can purify in-house. A published 3-step alcohol + H2O2 + separation-funnel protocol from a 2020 Iraqi research team drops impurities to <0.6% with <5% MWCNT mass loss. The full protocol takes 1-2 days of lab time per batch. Read the methodology Spotlight here. The economics work out when your lab time is cheap and your material cost is the constraint.
Functionalized MWCNTs (COOH, OH, NH2)
Every MWCNT line ships in both pristine and pre-functionalized variants — if your application needs functional groups (carboxyl, hydroxyl, or amine side groups) attached to the MWCNT sidewall, you don't need to DIY-functionalize unless you have a specialty chemistry requirement. The breadth of available functionalization differs by line:
- Standard MWCNT (98%) has the broadest functionalization catalog: COOH in 7 diameter SKUs (8, 8-15, 10-20, 20, 20-30, 30-50, 50 nm), OH in 6 SKUs (8, 8-15, 10-20, 20-30, 30-50, 50 nm), NH2 in 20 nm, plus Short COOH and Short OH variants in matched diameters for applications needing shorter aspect ratios. The Standard line is also the only line offering NH2 functionalization off the shelf.
- Industrial Grade (90%) offers COOH in 10-30 and 20-40 nm, OH in 10-30 and 20-40 nm. Lower per-gram cost; suitable when the functionalized MWCNT goes into a composite or bulk application where purity isn't the constraint.
- Graphitized MWCNT (99.5%+) offers COOH-Graphitized and OH-Graphitized each in 5 diameter SKUs (8-15, 10-20, 20-30, 30-50, 50 nm). The premium tier for catalysis, biomedical, and high-purity sensor work where pre-purified material is essential.
DIY functionalization is still an option for groups with established surface-chemistry workflows or specialty group requirements (e.g., PEG, biotin, custom ligands) that we don't offer pre-attached. But for standard COOH, OH, or NH2 work, the pre-functionalized variants save you the lab time and give consistent batch-to-batch chemistry.
Common Mistakes Researchers Make
- Buying Graphitized MWCNT for a polymer composite percolation network. The graphitization doesn't help your performance; you're paying for purity that doesn't change the percolation threshold or the bulk conductivity. Industrial Grade is the right call.
- Buying Industrial Grade MWCNT for a fuel cell electrocatalyst support. The ~10% catalyst-metal residues will skew your active-site composition and bias your performance measurements. Graphitized is essential.
- Buying Standard MWCNT for a published paper without specifying the lot. If you don't report the diameter, length, and purity grade in your Methods section, reviewers will ask. The Standard catalog has seven diameter SKUs — pick the right one and cite it explicitly.
- Mixing batches from different lots without re-characterizing. Even within a single product line, lot-to-lot variation matters for reproducibility. Order enough material upfront for your full experimental campaign.
- Defaulting to the cheapest option because your PI is cost-pressured. If you end up scattering data and re-running experiments because the impurity load contaminated your measurements, the cheaper material was the more expensive choice. Match purity to application.
Browse the Three Lines
Industrial Grade MWCNT (90%)
Composites, EMI shielding, conductive coatings, cement, antistatic films, bulk percolation networks.
Browse Industrial Grade →Standard MWCNT (98%)
Academic research, ink formulation, electrospinning, supercap electrodes, hybrid material R&D, DIY-functionalization precursor.
Browse Standard MWCNT →Graphitized MWCNT (99.5%+)
Catalysis, biomedical, fuel cells, single-tube electronics, high-purity sensors, photovoltaic / photoelectrochemical electrodes.
Browse Graphitized MWCNT →Frequently Asked Questions
What's the actual difference between Industrial Grade, Standard, and Graphitized MWCNT?
Three things differ: purity, post-treatment, and price. Industrial Grade is CVD-synthesized and minimally post-processed at 90% purity (the other 10% is residual catalyst metals plus amorphous carbon and nano-capsule byproducts). Standard MWCNT is purified to 98% research grade. Graphitized MWCNT takes the Standard material and applies a high-temperature thermal treatment that vaporizes catalyst metals and converts amorphous carbon to graphitic structure, reaching 99.5% plus purity. The three tiers price approximately at 1x / 2-3x / 5-10x of each other depending on diameter and quantity.
How do I know which one I need?
Ask whether impurities would affect your measurement or product performance. If you're building a polymer composite for mechanical reinforcement or electrical percolation, the 10% impurity load in Industrial Grade is invisible to your application — use it and save money. If you're doing catalysis where residual Mo, Co, or Fe would compete with your engineered active sites, you need Graphitized. If you're doing general academic research where reproducibility and clean characterization data matter, Standard MWCNT is the workhorse line.
Can I just buy the cheapest one and purify it myself?
Yes, if your lab time is cheap relative to material cost. A published 3-step alcohol plus H2O2 plus separation-funnel protocol drops Industrial Grade MWCNT impurities to less than 0.6 percent with less than 5 percent mass loss, taking 1 to 2 days per batch. This is the DIY-economics path. If your lab time is expensive or you need consistent batch-to-batch purity without your team running purification protocols, buy Graphitized.
Do all three lines have the same diameter SKUs?
No. Industrial Grade comes in 10 nm singular, 10-30 nm combined range, and 20-40 nm. Standard MWCNT has the broadest catalog: 8 nm, 8-15 nm, 10-20 nm, 20 nm, 20-30 nm, 30-50 nm, 50 nm. Graphitized MWCNT comes in 8-15 nm, 10-20 nm, 20-30 nm, 30-50 nm, 50 nm. Note that the 10-30 nm combined range is unique to Industrial Grade — if a paper cites that diameter, it identifies the IG line specifically.
What about functionalized MWCNT (COOH, OH, NH2)?
All three lines ship in both pristine and pre-functionalized variants. Pristine: every diameter SKU is available unfunctionalized in all three lines (Industrial Grade, Standard, Graphitized). Pre-functionalized: Standard MWCNT (98%) has the broadest catalog — COOH in 7 diameters, OH in 6 diameters, NH2 in 20 nm, plus Short COOH and Short OH variants. Industrial Grade offers COOH and OH in 10-30 and 20-40 nm. Graphitized offers COOH and OH in 5 diameter SKUs (8-15 to 50 nm). NH2 is only available in the Standard line.
Will my paper's reviewers expect a specific grade?
Reviewers will expect you to specify the diameter, length, purity, and supplier of any commercial MWCNT you used in your Methods section. For most academic research, Standard MWCNT at the appropriate diameter is the defensible choice and is widely cited in peer-reviewed literature. For catalysis, biomedical, or high-purity electronics work, reviewers will increasingly expect to see Graphitized or equivalent post-purified material justified in the Methods. For composite engineering papers, Industrial Grade is perfectly acceptable if the impurities don't affect what you're measuring.
How do I cite Cheap Tubes products in a paper?
Cite the specific SKU name (e.g., “Industrial Grade Multi Walled Carbon Nanotubes 10-30 nm, Cheap Tubes Inc., Grafton, VT, USA”) along with the diameter, length, and purity grade. Use cheaptubes.com URLs in your bibliography if your journal accepts URL references. Reproducibility downstream depends on other researchers being able to source the same material.