Figure | High-resolution dry patterning of single-walled carbon nanotube films via membrane imprinting for tunable THz optics and strain sensing. (IMAGE)
Caption
Figure | High-resolution dry patterning of single-walled carbon nanotube films via membrane imprinting for tunable THz optics and strain sensing.
The graphical abstract illustrates a novel, waste-free, one-step, and entirely dry approach for producing spatially patterned thin films of single-walled carbon nanotubes (SWCNTs) with feature sizes down to ~100 µm, without any post-growth processing or chemical treatment.
Fabrication (left). SWCNTs are synthesized continuously by aerosol chemical vapor deposition (aerosol CVD). The aerosol is directed onto a nitrocellulose filter membrane whose surface has been selectively clogged in advance by mechanical imprinting with a laser-structured metal stencil. The collected SWCNT film is subsequently dry-transferred onto any target substrate — including elastic elastomers — without liquids, surfactants, or chemical treatment, preserving the intrinsic purity and electrical properties of the nanotubes.
Application 1 — mechanically tunable THz spiral zone plate (top right). The patterning method was used to fabricate a four-charge spiral zone plate (SZP) by transferring the SWCNT film onto a stretchable elastomer. Due to the high THz absorption of the SWCNT film combined with its mechanical compliance, the SZP acts as a tunable diffractive optic: applying 0–12% radial strain continuously shifts the focal distance by up to 44%. The four-arm intensity pattern at the focal plane (top right inset) carries orbital angular momentum characteristic of a charge-4 vortex beam.
Application 2 — high-sensitivity SWCNT strain sensor (bottom right). The newly developed patterning approach was employed to fabricate serpentine SWCNT based strain gauges. The piezoresistive response (ΔR/R₀) of the sensors — schematically represented by the nonlinear ΔR/R₀ vs. strain curve in the center of the abstract — significantly outperforms the state of the art: the best gauge factor obtained 5.1 in the elastic regime, corresponding to approximately 10 times improvement over the best literature reported value for an equivalent geometry (Arana et al., 2023) and ~4× improvement in the maximum linear gauge factor. Cyclic testing over 3000 load–unload cycles confirmed stable response with no drift, demonstrating the robustness of the dry-transfer SWCNT films on rigid substrates.
Taken together, the approach combines the scalability and purity of aerosol CVD with the geometric precision of laser-structured metal stencils to yield reusable, chemically clean patterned SWCNT membranes suitable for single-step fabrication of advanced optical and electronic devices.
Credit
Dmitry V. Krasnikov et al.
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CC BY