DNA‐Wrapped Single‐Walled Carbon Nanotube Hybrid Fibers for supercapacitors and Artificial Muscles

Abstract

Multifunctional carbon nanotube (CNT) composite fibers are currently of considerable interest in applications where actuation and energy-storage functions are highly desirable, such as electronic textiles. CNT fibers have been shown to function as excellent electrochemical supercapacitors giving specific capacitances of 100 F g -1 [1] . CNT assemblies can also produce useful actuation strains when electrochemically charged [2] and can potentially operate to high stresses because of the excellent mechanical properties of individual CNTs. The development of CNT fibers that simultaneously produce a high capacitance and useful actuation performance remains a challenge however, because the high surface area needed for high capacitance significantly reduces the strength and compromises actuation performance. To date, it has not been possible to develop an ion-conducting binder that mechanically stabilizes the CNT assembly, maintains electrical connectivity between nanotubes, and allows free transport of ions between the nanotubes and an external electrolyte. Pioneering work by Poulin [3] and Baughman [4] have established processing methods for preparing continuous fibers of CNTs and CNT composites that are ideal for electronic textiles. Various studies on these fibers and other CNT assemblies have highlighted the difficulties involved in producing mechanically robust, high-conductivity and high-surface-area electrodes. While single wall carbon nanotube (SWNT) fibers containing ∼40 % poly(vinyl alcohol) (PVA) binder give exceptional mechanical properties, their conductivity is very low at 0.2 S cm -1 .[1] The binder can be removed by pyrolysis to improve conductivity so that the fibers can be operated as electromechancial actuators. While quite high actuation stresses were obtained in these thermally annealed CNT fibers, their low flexibility and high creep during charge and discharge were noted as significant problems.[5] Similarly, fibers spun without the aid of a polymer binder [1] produce high conductivities (140 S cm -1 after thermal annealing) and capacitances (100 F g -1 ) but are mechanically fragile. To resolve these problems, crosslinked DNA has been chosen as a binder for CNT fibers. DNA is a good candidate for improved electrical conductivity for electrochemical devices with CNTs, as DNA has electrical characteristics similar to those of semiconducting diodes in that current flows in one direction only. [6][7][8] In addition, DNA more effectively coats, separates, and solubilizes CNTs than other surfactants because of the large surface area of its phosphate backbone, which interacts with water, and there are many bases in DNA that can bind to CNTs.[9] Therefore, DNA wrapping can debundle CNTs in high concentration CNT dispersions. Consequently, DNA wrapping may improve electrochemical actuation and capacitance of nanotubes in composite fibers by its improved electrical conductivity, high CNT surface area and enhanced mechanical stability due to the p-p interaction between the DNA and the CNT sidewall. We rep...

Nano-yarn carbon nanotube fiber based enzymatic glucose biosensor

“…Because of the sp 2 carbon atoms in the polycyclic aromatic hydrocarbon chemistry of the graphene tubes in CNTs and the exclusive Schiff's base glutaraldehyde crosslinking reaction of GOx-BSA proteins, covalent interactions between CNTs and GOx-BSA layers are not feasible. Hence, the GOx layer is expected to interact with CNT fiber non-covalently, which is consistent with reports that different enzymes, polypeptides and DNA can interact non-covalently with CNT [28][29][30][31][32][33][34][35]. The interactions between proteins and CNT are reported to involve many types of non-covalent forces, including electrostatic, hydrogen bonding, hydrophobic and π-π interactions; and strong non-covalent interactions were also demonstrated between GOx and DWNTs [34].…”

A Bioactive Carbon Nanotube‐Based Ink for Printing 2D and 3D Flexible Electronics

“…The electrical conductivity of the dried hybrid film was 24 ± 1.8 S/cm as measured by a four-point probe method. [27] . Even after drying (films containing ~47% GelMA/DNA which was confirmed by thermogravimetric analysis (TGA), Figure S2 ), the conductivity of these films was higher than 2D printed graphene patterns (0.1 – 100 S/m).…”

“…The enhanced mechanical stability of the ink might be due to the strong the π–π and hydrophobic interactions between the GelMA/DNA chains and MWCNTs sidewalls. [27] …”

“…In Figure 2i, the CV curve showing the rectangular shape revealed that the sample had a high electrical conductivity compared with pristine GelMA hydrogel (Figure S11 ). [27] The sample had a higher capacitance value (30.48 ± 6.47 F/g in PBS and 29.4 ± 4.7 F/g in cell culture media) compared to that of SWCNT fibers spun with ~7 F/g. It was similar to that of typical SWCNT mats with ~30 F/g in 2 M NaCl, which had higher salt concentrations compared with PBS (~150 mM).…”

Triad CNT-NPs/Polymer Nanocomposites: Fabrication, Characterization, and Preliminary Antimicrobial Study

“…[18] Several studies are particularly devoted to the generation of SWCNT-DNA nanoarchitectures via noncovalent interaction for multiple application include electronics, biomedical, and were reviewed elsewhere. [19] Shim et al reported the mechanical strength of PVA polymer can be improved by incorporation of CNTs. [1] Besides, incorporation of POSS into resins gives rise in tensile strength and mechanical properties, and can 346 R. SUBBIAH ET AL.…”