Ultra-Long SWCNT for Transparent Conductive Films: New 100 micron, 99.5% Purity Product Spec-Matched to Recent Research

Cheap Tubes is launching a new ultra-long, high-purity single-walled carbon nanotube product engineered for transparent conductive films, conductive coatings, and electromagnetic interference shielding applications where aspect ratio and chemistry purity dominate performance. Specifications: 99.5% ± 0.5% purity, ≥100 micron tube length, 1-2 nm outer diameter, 800-1,400 m²/g specific surface area, Fe content ≤5,000 ppm, six-year shelf life. This Spotlight contextualizes the new product through two recent peer-reviewed studies that establish what ultra-long CNT transparent conductive films can do and what role Cheap Tubes has played in the TCF research record. The Hebrew University of Jerusalem demonstrated 1.5 to 1.2 kohm/sq sheet resistance at 85-88% transmittance in ultra-long CNT TCF heaters that survived 5,000 bending cycles and reached 100 °C in 20 seconds at 100 V (Dubnov et al., Coatings 2025); KAUST demonstrated a Cheap Tubes COOH-SWCNT + GNP heating-rate-triggered 3D conducting network for noncontact moisture sensing (Tai & Lubineau, Scientific Reports 2016). Both lines of work map directly to the new Cheap Tubes 99.5% / 100 μm material.

The Application: Ultra-Long SWCNT for Transparent Conductive Films

Transparent conductive films are the foundational component in flexible displays (OLED), touch panels, transparent electrodes for solar cells, smart windows, flexible heaters, and wearable electronics. The benchmark material has been indium tin oxide (ITO), but ITO has three structural problems: brittleness (cracks under bending), oxidation susceptibility, and indium supply / cost constraints. Carbon nanotube films are the leading alternative because they offer:

• Mechanical compliance — nanotube networks tolerate large strain and bending without conductivity loss.
• High optical transparency at appropriate loading because the percolating network needs only a small mass fraction to conduct.
• Chemical robustness across a wider operating window than metal films.
• Scalable wet processing compatible with roll-to-roll and printing methods.

The performance ceiling on a CNT TCF is set by the geometry of the percolating network. Shorter, lower-aspect-ratio tubes need more material per unit area to form a conductive percolating network, which costs both transparency (more material absorbs more light) and flexibility (denser networks crack at lower strain). Longer tubes form percolating networks at lower volume fraction, so the equivalent sheet resistance is achieved at higher transparency. Tube length is the property that most directly improves the trade-off curve between transparency and conductivity.

The Research Context — What Ultra-Long CNT TCFs Can Do

Dubnov et al., Coatings (2025) — ultra-long CNT TCF heaters with industrial-tier durability

The Magdassi group at the Hebrew University of Jerusalem, with collaborators at Tortech NanoFibers, published a 2025 demonstration of ultra-long CNT-based flexible transparent heaters (TCFs) in Coatings. The film stack: an aqueous ink of ultra-long mix-walled CNTs (TorTech CNTM1, length >100 μm, potentially cm scale) processed via flow coating on polyethylene terephthalate, glass, and polycarbonate substrates. The reported performance:

• Sheet resistance: 7.5 kΩ/sq single layer to 1.5 kΩ/sq triple layer.
• Transmittance: 85-88% single layer at 550 nm; ~57% triple layer.
• After flash-photonic heating treatment: sheet resistance reduced by up to 80% (from 7.5 to 1.2 kΩ/sq).
• Mechanical durability: stable sheet resistance over 5,000 bending cycles with no degradation in heating performance.
• Joule heating: ~100 °C in 20 seconds at 100 V.
• Process: water-based, low-temperature, compatible with PET and polymer substrates.

The performance is in the range that suits demisting / defogging films, smart windows, wearable thermal therapy, and printable electronic textiles. Critically, the paper explicitly attributes the performance to ultra-long CNT tubes (length >100 μm) reducing junction density per unit area — the same physical mechanism that makes the new Cheap Tubes 99.5% / 100 μm material a fit for this application class. Note: this study used TorTech ultra-long CNT supply (mix-walled), not Cheap Tubes material. It is cited here as the technology demonstration that establishes what ultra-long CNT TCFs are capable of.

Tai & Lubineau, Scientific Reports (2016) — Cheap Tubes SWCNT and GNP in a TCF moisture-sensing array

From the Materials section of the paper (verbatim): "Carboxyl group (-COOH) functionalized SWCNTs were purchased from CheapTubes, Inc.: tubes had an outer diameter of 1-2 nm, a length of 5-30 μm, over 95 wt.% purity, and 2.56 wt.% COOH groups. Graphene nanoplatelets were purchased from CheapTubes, Inc.: tubes had a diameter of 2 μm, a surface area > 700 m²/g, and over 99 wt.% purity."

Tai & Lubineau at KAUST (King Abdullah University of Science & Technology) used Cheap Tubes COOH-SWCNT and Cheap Tubes GNP in a heating-rate-triggered 3-dimensional porous SWCNT/PEDOT:PSS conducting network, which they call SWCNT-PTCFs (PEDOT-based Transparent Conductive Films). The application: a 5×5 pixel array transparent conductive film for noncontact moisture sensing — the device responded to humidity changes from a human index finger held at varying distances. Specifications and key outcomes:

• Drop-cast lithography of a Cheap Tubes COOH-SWCNT / PEDOT:PSS aqueous ink, baking-rate controlled to form 3D porous networks.
• Sheet resistance tunable from 139 kΩ/sq down by orders of magnitude with the porous architecture.
• Noncontact moisture-sensing 5×5 pixel array demonstrated — humidity field from a human fingertip detected at variable distance.
• Established Cheap Tubes COOH-SWCNT as a viable feedstock for TCF research at the time, at >95% purity and 5-30 μm length.

This is the precedent: Cheap Tubes SWCNT was used in published TCF research at the prior generation of length/purity specifications. The new 99.5% / 100 μm product extends the spec envelope by an order of magnitude in length and brings purity up from >95% to 99.5%.

The New Cheap Tubes Ultra-Long SWCNT — Spec Sheet

Spec Comparison — Cheap Tubes vs Ultra-Long CNT Sources vs OcSiAl TUBALL

Researchers evaluating ultra-long CNT options for TCF, EMI shielding, and conductive-coating applications typically benchmark against three sources: ultra-long CNT specialty suppliers (e.g., the TorTech ultra-long CNT used in Dubnov 2025), the industrial-scale OcSiAl TUBALL SWCNT product (the largest-volume commercial SWCNT supply), and Cheap Tubes. Head-to-head spec comparison:

The differentiation is straightforward: the new Cheap Tubes material delivers the length advantage that ultra-long CNT specialty suppliers exploit, paired with the purity and chemistry control that industrial SWCNT supply chains usually trade off. Pure SWCNT (vs mix-walled) matters for TCF applications where percolation threshold and transparency are key — mix-walled CNT introduces MWCNT mass that does not contribute proportionally to percolation. High purity matters for any application where amorphous carbon and metal-catalyst residue would introduce optical loss, electrochemical artifact, or unwanted reactivity.

Application Areas for the New Ultra-Long SWCNT

• Transparent conductive films (TCF) — the headline application, where length-dependent percolation lowers required loading for a given sheet resistance, raising transmittance. Spec-matched to Dubnov 2025 demonstration class.
• Flexible heaters, defoggers, demisters — same TCF technology base, with Joule-heating applications in automotive, eyewear, smart windows, wearable therapeutic devices.
• EMI shielding films — high-aspect-ratio SWCNT enables thin, lightweight shielding (see Yang et al. Carbon 2023 in our EMI shielding Spotlight).
• Conductive composites at low loading — percolation threshold drops with aspect ratio. Lower loading means lower viscosity, easier processing, lower cost-per-unit-conductivity.
• Structural reinforcement — aspect ratio drives mechanical reinforcement gains. Long tubes bridge particle boundaries more effectively than short tubes.
• Stretchable conductors — long-aspect-ratio percolation networks tolerate higher strain before electrical disconnection.
• Electrochemistry, sensors, fuel cells — high SSA (800-1,400 m²/g) with low metal contamination is the right combination for clean baseline electrochemistry and well-defined electrode interfaces.

Order the New Ultra-Long Cheap Tubes SWCNT

The new ultra-long, high-purity SWCNT is available now from Cheap Tubes at research and production volumes. Available variants: pristine, COOH-functionalized, NH₂-functionalized, OH-functionalized (special order). Full Technical Data Sheet, Safety Data Sheet, and batch-specific Certificate of Analysis included with every shipment. Production-scale supply, custom dispersions, and application-specific formulation support available on request.

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