TAILORING CARBON NANOTUBE FIBERS FOR WEARABLE SMART DEVICES

J. Di

, Q. Li

, Q. Zhang

1Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China - Suzhou And China)

*email: [email protected]

Carbon nanotube fibers are ideal multifunctional electronic materials due to its unique combination of structural, mechanical, electrical and thermal properties, enabling them promising candidates for developing intelligent materials and devices in areas of sensing, actuating and computing fields etc.. In my talk, I will introduce our recent research progress in the strengthening, shaping and functionalization of CNT fibers for wearable smart devices. My talk includes three aspects: 1) Gas-phase spinning of high-performance CNT fibers and wet functionalization of CNT fibers with desirable morphology, strength and conductivity;

2)Fabrication of CNT fibers for artificial muscles with multifunctionalities and knittability. For instance, through the construction of a high-twist-pervaded structure, the CNT fiber produced a large reversible contraction of 62.4% under high load (10000 times the mass of the yarn muscle) and low driving voltages (<5 V). Interestingly, the fiber can be also fabricated as an artificial neuromuscular device by multilayered coaxial integration strategy, making it with adaptive actuation upon environmental change; 3) Fabrication of fiber-shaped self-powered sensing devices for smart textile. For instance, a fiber-shaped artificial optoelectronic synapse was constructed with double-twisted architecture consisting of high-density TiO2-x and MoS2 arrays.

Such a simple structure can emulate both electrical and light-induced synaptic functions such as excitatory postsynaptic current, short/ long-term plasticity, and ‘‘learning-forgetting-relearning’’

behavior. As a proof-of-concept demonstration, multiple fiber devices were woven into commercial textiles to form optoelectronic synapse arrays for perception and memory of image information. Finally, I will show my viewpoints on the future development of CNT fibers and their promise in smart textiles and composites.

References

Y.L. Wang, J.T Di, Q.W. Li, et al., Nano Energy 102 (2022) 107609;

L.Z. Dong, J.T. Di , Q.W. Li, Science Advances 8 (2022) 7033;

M. Ren, J.T. Di, Q.W. Li, ACS Nano 16 (2022) 15850−15861;

Q. Gong, Q.W. Li, J. Zhang, Advanced Functional Materials 32 (2022) 2107360.

EVIDENCE AND ANALYSIS OF DISCONTINUOUS THERMODYNAMIC PROPERTIES UNDER EXTREME ONE DIMENSIONAL CONFINEMENT – THE CENTER FOR ENHANCED NANOFLUIDIC TRANSPORT (CENT)

M. Strano

1Massachusetts Institute of Technology - Cambridge (United States)

*email: [email protected]

Not all nanopores are created equal. By definition, all have characteristic diameters or conduit widths between approximately 1 and 100 nm. However, the narrowest of such pores, perhaps best called Single Digit Nanopores (SDNs), defined as those with less than 10 nm diameters, have only recently been accessible experimentally for precision transport measurements. To address the challenges of bridging the deficiencies of theory and experiment for fluids confined within the most extreme conduits, we have formed the Center for Enhanced Nanofluidic Transport (CENT). This talk will outline some of the major successes of this collaboration in understanding the thermodynamics and transport through SDN systems. In one recent advance, highlighted in this presentation, we develop a platform based on Raman spectroscopy and ultra- long carbon nanotubes with diameters less than 3 nm suspended over electron microscopy windows to identify and study new types of vibrational coupling to the CNT environment.

Electron diffraction assigned Double Walled Carbon Nanotubes (DWNT) suspended across with

20 μm slit on 1,500 μm transmission electron microscopy (TEM) windows are used to probe in

vacuum an enormous 10 to 15% Radial Breathing Mode (RBM) downshift shift with increasing

temperature that is both reversible and robust over dozens of cycles. A new analysis based on a

harmonic oscillator model is able to assign the hyperbolic trajectory to a reversible increase in

damping, generating a shift that is the reverse of prior expectations. The environmental source of

the coupling is assigned to graphitic ribbons shown by TEM to decorate the surface up to an axial

coverage of 60%. A linear, strain-dependent coupling of the ribbon fragments driven by thermal

expansion of the supporting nanotube describes the distinctive cusp that appears throughout the

91 temperature scans of 3 distinct DWNTs. We find that each connection of the fragments with

the DWNT surface keeps the ratio of spring to damping frequencies constant, producing a

remarkable saturation of the RBM frequency in the low-tension limit. The high fidelity of the

oscillatory model shows that the RBM has negligible intrinsic temperature dependence and that

evidence for impurity-induced damping as a confounding variable is commonly present in

experiments previously thought to be on pristine systems. Overall, these findings significantly

increase our understanding of the environmental coupling of 1D nano-mechanical systems,

providing the basis for new technological applications and improved spectral analysis. This

platform sets forth a new and reliable approach for studying the environmental coupling of the

CNT to phases of interest for study, with future work demonstrating its utility for investigating

fluids in single digit nanopores under extreme confinement. CENT is organized around critical

gaps in our understanding of nanoscale hydrodynamics, molecular sieving, fluidic structure, and

thermodynamics. These knowledge gaps are, in turn, an opportunity to discover and understand

fundamentally new mechanisms of molecular and ionic transport that may inspire novel

membranes for separations, new gas-permeable materials and energy storage devices.

CLASSIFICATION OF 2D CARBON ALLOTROPES V. Meunier

, L. Macmillan

, E. Costa Girão

1The Pennsylvania State University - State College, Pa (United States)

2Universidade Federal do Piauí - Piauí (Brazil)

*email: [email protected]

A unified taxonomy for sp

nanocarbon allotropes in two dimensions (2D) is proposed where structures are assigned a unique symbol associated with the geometry of each allotrope.[1] The naming scheme will be demonstrated for all the structures described in the literature and is further illustrated for a number of other topology-allowed carbon sp

systems. The symbol is easy to use and gives a direct access to geometrical features such as the number of polygons and their arrangement. It facilitates the classification of structures reported in the literature, where many such structures are found to have been assigned a name based on each author's somewhat arbitrary choice. The naming scheme can be applied to 1D systems and has the potential to be expanded to mixed sp

-sp

carbon system as well as non-carbon nanostructures in 2D. In this talk, I will also present a search algorithm for 2D structures and show why not all structures obeying Euler criteria are acceptable solutions.

Example of the application of the proposed naming scheme where polygon counts and lattice symmetries are used.

References

[1] Classification of sp2-bonded carbon allotropes in two dimensions, EC Girão, A Macmillan, V Meunier, Carbon 203, 611-619 (2023)

CARBON NANOTUBE TRANSISTORS PROGRESS TOWARDS