Lignin is considered as a promising bio-sourced precursor for more sustainable and low-cost carbon fibers (CFs). However, lignin-based CFs generally have a poor graphitic structure, compared to polyacrylonitrile CFs. In this paper, we present an original approach that uses graphene oxide liquid crystal (GOLC) as a templating agent to promote the formation of graphitic structure in the fibers at low carbonization temperature. Both lignin and hybrid lignin/GOLC CFs were carbonized/graphitized up to 2700 °C. Structural analyses by X-ray diffraction, Raman spectroscopy and electrical measurements manifest a significant improvement in graphitic structure and a preferred orientation of graphene planes for lignin/GOLC fibers. These effects are the result of axial propagation of the templated graphitic order nucleated by the large GO flakes. The current approach reveals the possibility of preparing low-cost lignin-based CFs with improved graphitic structure and high electrical conductivity at low temperature for electrochemical or smart textile applications.

Microenergy storage devices are appealing and highly demanded for diverse miniaturized electronic devices, ranging from microelectromechanical system, robotics, to sensing microsystems and wearable electronics. However, making high‐energy microcapacitors with currently available printing technologies remains challenging. Herein, the possibility to use latex polyvinylidene fluoride (PVDF) as aqueous ink for making dielectric capacitors at the microscale is shown. The dielectric properties of printed microcapacitors can be optimized based on a novel approach, i.e., mixing PVDF latex with polyvinyl alcohol (PVA) to realize dielectric organic nanocomposites. The PVA prevents the coalescence of PVDF nanoparticles and serves as a continuous matrix phase with high dielectric breakdown strength. While the well‐dispersed PVDF nanoparticles serve as highly polarizable and isolated domains, providing large electric displacement under high fields. Consequently, a high discharged energy density of 12 J cm−3 is achieved at 550 MV m−1. These printed microcapacitors demonstrate mechanical robustness and dielectric stability over time.

The detection of Pb 2+ was performed using a completely inkjet printed multi-walled carbon nanotube (IJP-MWNT) sensor employing anodic stripping voltammetry (ASV) using Osteryoung square wave stripping voltammetry (OSWV) as the detection step. The MWNT ink was prepared in water using bile salts (BS) as a surfactant, which was further washed out with DI water and then remaining MWNT was used as an electrode surface. The IJP-MWNT electrode was used as the working electrode with a platinum wire and glass capillary Ag/AgCl as auxiliary and reference electrode, respectively. The electrode was optimized in 0.1 M acetate buffer (pH = 4.3) and had a linear range of 5-50 ppb (R 2 = 0.98235) a sensitivity of 20.15 nA/ppb and a limit of detection (LOD) of 1.632 ppb for Pb 2+. The analytical applicability of electrode was tested in a real drinking water sample (i.e.) Cincinnati tap water with a linear range of 15-70 ppb (R 2 = 0.98752) a sensitivity of 2.654 nA/ppb and a LOD of 1.269 ppb for Pb 2+ .

We propose a simple and original way to prepare surfactant-free SWNT/hydrosoluble polymer composites with high concentrations of individual SWNT. We first disperse single-walled carbon nanotubes (SWNT) in aqueous suspensions using bile salts (BS), and we mix them with a solution of hydrosoluble polymer, poly(vinylpyrrolidone) (PVP) or poly(vinyl alcohol) (PVA). We measure the yield using visible–NIR absorption spectroscopy, and we probe both the chemical environment of the nanotubes and the effectiveness of individualization from coupled Raman/photoluminescence studies. We evidence a direct exchange of BS molecules and PVA chains at the surface of SWNT. By contrast, no direct exchange is observed with PVP. On the other hand, we show that a simple dialysis process leads to the preparation of aqueous suspensions of SWNT covered by PVP or PVA with high yields and an effective individualization of the nanotubes.

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The main hurdle preventing the widespread use of single-walled carbon nanotubes remains the lack of methods with which to produce formulations of pristine, unshortened, unfunctionalized, individualized single-walled carbon nanotubes, thus preserving their extraordinary properties. In particular, sonication leads to shortening, which is detrimental to percolation properties (electrical, thermal, mechanical, etc.). Using reductive dissolution and transfer into degassed water, open-ended, water-filled nanotubes can be dispersed as individualized nanotubes in water-dimethyl sulfoxide mixtures, avoiding the use of sonication and surfactant. Closed nanotubes, however, aggregate immediately upon contact with water. Photoluminescence and absorption spectroscopy both point out a very high degree of individualization while retaining lengths of several microns. The resulting transparent conducting films are 1 order of magnitude more conductive than surfactant-based blanks at equal transmittance.

The detection of Pb 2+ was performed using a completely inkjet printed multi-walled carbon nanotube (IJP-MWNT) sensor employing anodic stripping voltammetry (ASV) using Osteryoung square wave stripping voltammetry (OSWV) as the detection step. The MWNT ink was prepared in water using bile salts (BS) as a surfactant, which was further washed out with DI water and then remaining MWNT was used as an electrode surface. The IJP-MWNT electrode was used as the working electrode with a platinum wire and glass capillary Ag/AgCl as auxiliary and reference electrode, respectively. The electrode was optimized in 0.1 M acetate buffer (pH = 4.3) and had a linear range of 5-50 ppb (R 2 = 0.98235) a sensitivity of 20.15 nA/ppb and a limit of detection (LOD) of 1.632 ppb for Pb 2+. The analytical applicability of electrode was tested in a real drinking water sample (i.e.) Cincinnati tap water with a linear range of 15-70 ppb (R 2 = 0.98752) a sensitivity of 2.654 nA/ppb and a LOD of 1.269 ppb for Pb 2+ .