<i>In situ</i> alignment of graphene nanoplatelets in poly(vinyl alcohol) nanocomposite fibers with controlled stepwise interfacial exfoliation

Xu, Weiheng; Jambhulkar, Sayli; Verma, Rajendra Kumar; Franklin, Rahul; Ravichandran, Dharneedar; Song, Kenan

doi:10.1039/c9na00191c

Cited by 21 publications

(20 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A multichanneled spinneret was 3D printed using selective laser sintering with cobalt‐chromium (CoCr) based on our previous design, as listed in Figure S1 and Table S1 in the Supporting Information. [ 39 ] Two types of TPU, namely, Soft35 and 1185A, were used due to their different affinities to nonsolvent during coagulation, polymer chain length, and macromolecular crosslinking density. For fiber spinning, a pure Soft35 polymer solution, an MWCNTs/GnPs/Soft35 mixture, and a pure 1185A polymer solution were injected into the inner, middle, and outer spinneret inlet, respectively, (see details listed in the Experimental Section).…”

Section: Resultsmentioning

confidence: 99%

Bioinspired, Mechanically Robust Chemiresistor for Inline Volatile Organic Compounds Sensing

Ravichandran

Jambhulkar

et al. 2020

Adv Materials Technologies

Self Cite

View full text Add to dashboard Cite

portable chemiresistive devices based on the resistance change of metal oxide semiconductors upon absorbing VOCs. [8-14] In particular, when nanostructured, their detection capabilities to analytes could reach down to a few parts per billion (ppb) and with good response time. [15] Thus, they are ideal for important biological applications, such as breath and respiratory diagnostics. [16] Their high sensitivities are nevertheless coupled with elevated operating temperatures, usually several hundred degrees Celsius as well as low thermal stability under various environments. [17-19] This limits their application in multifunctional devices, especially due to the low survivability of the rigid metaloxide devices under complex dynamic or fatigue conditions. On the other hand, conductive polymer nanoparticle composites have demonstrated stable performances under extreme conditions, [20] can be scalably manufactured, [21-23] and meet compliance requirements of wearable electronics. [24,25] Their gas sensing functionalities, based on the Flory-Huggins interaction parameters between solvents and polymers, have also been investigated with various polymer matrices and nanoparticles. [26-30] Currently, the main performance-limiting factor is their low sensitivity, usually in the range of several parts per thousand to a few hundred parts per million (ppm). Increasing the surface area is one of the most efficient methods to increase sensitivity, such as in macroscale helical structure, [31] microscale scaffolds, [32] and nanoscale nanofibers. [33] Notably, nature provides inspirations that have unparalleled advantages in material design and fabrication. [34-37] Herein, we introduce a multilayered, porous, and hollow fiber sensor with enhanced functionalities mimicking the metaxylem structure of vascular plants (Figure 1a). Vascular plants utilize metaxylem conduits for the transpiration and transport of water and minerals from the ground to the leaves. In the presence of nutrient scarcity, transpiration efficiency is enhanced as pits on the cell wall facilitate the horizontal diffusion of water and minerals into adjacent cells. [38] Inspired by this highly ordered pit structure, we developed a multilayered polymer nanoparticle sensor with a self-induced hollow core that increases the surface area in macro-and microscales, with VOC sensitivity up to 15 ppm for xylene, There are advantages to polymer/nanoparticle composite-based volatile organic compounds (VOCs) sensors, such as high chemical and physical stability, operability under extreme conditions, flexible use in manufacturing, and low cost. Nevertheless, their lower limit of detection due to thickness-dependent diffusion has constrained their application. Inspired by the metaxylem in vascular plants and its vertical conduits and horizontal pits that enable efficient transpiration, a polymer/nanoparticle compositebased sensor is fabricated with a controllable, spontaneously formed, hollow core for inline VOCs transportation, and porous microstructure for radial direction d...

show abstract

Section: Resultsmentioning

confidence: 99%

Bioinspired, Mechanically Robust Chemiresistor for Inline Volatile Organic Compounds Sensing

Ravichandran

Jambhulkar

et al. 2020

Adv Materials Technologies

Self Cite

View full text Add to dashboard Cite

show abstract

“…In the Raman analysis of the CNTs, the G band around 1600 cm −1 resulted from the E 2g vibration mode, and the D band around 1350 cm −1 was assigned to the A 1g symmetry, which was associated to the defects (Figure 6a 1 ). [46] Based on the signature peaks, both red and green spectra showed the D band at 1350 cm −1 representing the CNT/PAN layer, while the blue region represented the PAN layer (Figure 6a 2, b 2 ). Interestingly, for CNT/PAN layers, the signals in the middle of the layer (colored red) showed higher average intensity than the signals in the edge of the layer (colored green) (I 90° in Figure 6a 2 ).…”

Section: Shear Stress-induced Nanoparticle Orientationmentioning

confidence: 99%

Hierarchically Structured Composite Fibers for Real Nanoscale Manipulation of Carbon Nanotubes

Ravichandran

Jambhulkar

et al. 2021

Adv Funct Materials

Self Cite

View full text Add to dashboard Cite

Carbon nanotube (CNT)-reinforced polymer fibers have broad applications in electrical, thermal, optical, and smart applications. The key for mechanically robust fibers is the precise microstructural control of these CNTs, including their location, dispersion, and orientation. A new methodology is presented here that combines dry-jet-wet spinning and forced assembly for scalable fabrication of fiber composites, consisting of alternating layers of polyacrylonitrile (PAN) and CNT/PAN. The thickness of each layer is controlled during the multiplication process, with resolutions down to the nanometer scale. The introduction of alternating layers facilitates the quality of CNT dispersion due to nanoscale confinement, and at the same time, enhances their orientation due to shear stress generated at each layer interface. In a demonstration example, with 0.5 wt% CNTs loading and the inclusion of 170 nm thick layers, a composite fiber shows a significant mechanical enhancement, namely, a 46.4% increase in modulus and a 39.5% increase in strength compared to a pure PAN fiber. Beyond mechanical reinforcement, the presented fabrication method is expected to have enormous potential for scalable fabrication of polymer nanocomposites with complex structural features for versatile applications.

show abstract

“…In this paper, we report the fabrication and characterization of polymethyl methacrylate (PMMA)-TiO 2 fibers, manufactured by low-cost and scalable methods ( Figure 1 a–c). In this investigation, two fiber architectures were studied [ 18 ]. The first was a porous PMMA fiber containing dispersed TiO 2 (D-phase), where the porous morphology entailed enhanced mass transport ( Figure 1 c 1,2 ).…”

Section: Introductionmentioning

confidence: 99%

PMMA-TiO2 Fibers for the Photocatalytic Degradation of Water Pollutants

Kanth

Prasad

et al. 2020

Nanomaterials

Self Cite

View full text Add to dashboard Cite

Titanium dioxide (TiO2) is a promising photocatalyst that possesses a redox potential suitable for environmental remediation applications. A low photocatalytic yield and high cost have thus far limited the commercial adoption of TiO2-based fixed-bed reactors. One solution is to engineer the physical geometry or chemical composition of the substrate to overcome these limitations. In this work, porous polymethyl methacrylate (PMMA) substrates with immobilized TiO2 nanoparticles in fiber forms were fabricated and analyzed to demonstrate the influence of contaminant transport and light accessibility on the overall photocatalytic performance. The influences of (i) fiber porosity and (ii) fiber architecture on the overall photocatalytic performance were investigated. The porous structure was fabricated using wet phase inversion. The core-shell-structured fibers exhibited much higher mechanical properties than the porous fibers (7.52 GPa vs. non-testability) and maintained the same degradation rates as porous structures (0.059 vs. 0.053/min) in removing methylene blue with comparable specific surface areas. The highest methylene blue (MB) degradation rate (kMB) of 0.116 min−1 was observed due to increases of the exposed surface area, pointing to more efficient photocatalysis by optimizing core-shell dimensions. This research provides an easy-to-manufacture and cost-efficient method for producing PMMA/TiO2 core-shell fibers with a broad application in water treatment, air purification, and volatile sensors.

show abstract

In situ alignment of graphene nanoplatelets in poly(vinyl alcohol) nanocomposite fibers with controlled stepwise interfacial exfoliation

Abstract: Exfoliated and aligned continuous graphene nanoplatelet channels with enhanced mechanical properties and superior electrical conductivity.

Cited by 21 publications

References 45 publications

Bioinspired, Mechanically Robust Chemiresistor for Inline Volatile Organic Compounds Sensing

Bioinspired, Mechanically Robust Chemiresistor for Inline Volatile Organic Compounds Sensing

Hierarchically Structured Composite Fibers for Real Nanoscale Manipulation of Carbon Nanotubes

PMMA-TiO2 Fibers for the Photocatalytic Degradation of Water Pollutants

Contact Info

Product

Resources

About