scholarly journals Electrical Percolation Threshold and Size Effects in Polyvinylpyrrolidone-Oxidized Single-Wall Carbon Nanohorn Nanocomposite: The Impact for Relative Humidity Resistive Sensors Design

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1435
Author(s):  
Bogdan-Catalin Serban ◽  
Cornel Cobianu ◽  
Niculae Dumbravescu ◽  
Octavian Buiu ◽  
Marius Bumbac ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Percolation Threshold ◽  
Threshold Value ◽  
Electrode Spacing ◽  
Humidity Sensors ◽  
Carbon Nanohorns ◽  
Electrical Percolation ◽  
Oxidized Carbon ◽  
Electrical Percolation Threshold ◽  
Percolation Thresholds

This paper reports, for the first time, on the electrical percolation threshold in oxidized carbon nanohorns (CNHox)–polyvinylpyrrolidone (PVP) films. We demonstrate—starting from the design and synthesis of the layers—how these films can be used as sensing layers for resistive relative humidity sensors. The morphology and the composition of the sensing layers are investigated through Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and RAMAN spectroscopy. For establishing the electrical percolation thresholds of CNHox in PVP, these nanocomposite thin films were deposited on interdigitated transducer (IDT) dual-comb structures. The IDTs were processed both on a rigid Si/SiO2 substrate with a spacing of 10 µm between metal digits, and a flexible substrate (polyimide) with a spacing of 100 µm. The percolation thresholds of CNHox in the PVP matrix were equal to (0.05–0.1) wt% and 3.5 wt% when performed on 10 µm-IDT and 100 µm-IDT, respectively. The latter value agreed well with the percolation threshold value of about 4 wt% predicted by the aspect ratio of CNHox. In contrast, the former value was more than an order of magnitude lower than expected. We explained the percolation threshold value of (0.05–0.1) wt% by the increased probability of forming continuous conductive paths at much lower CNHox concentrations when the gap between electrodes is below a specific limit. The change in the nanocomposite’s longitudinal Young modulus, as a function of the concentration of oxidized carbon nanohorns in the polymer matrix, is also evaluated. Based on these results, we identified a new parameter (i.e., the inter-electrode spacing) affecting the electrical percolation threshold in micro-nano electronic devices. The electrical percolation threshold’s critical role in the resistive relative-humidity sensors’ design and functioning is clearly emphasized.

MORPHOLOGICAL, OPTICAL AND ELECTRICAL CHARACTERIZATION OF SOLUTION PROCESSED MWNT–PEDOT:PSS NANOCOMPOSITE

2011 ◽  
Vol 25 (19) ◽  
pp. 2543-2556 ◽  
Author(s):  
MALTI BANSAL ◽  
RITU SRIVASTAVA ◽  
C. LAL ◽  
M. N. KAMALASANAN ◽  
L. S. TANWAR
Keyword(s):  
Percolation Threshold ◽  
Flexible Electronics ◽  
Electrical Characterization ◽  
Threshold Value ◽  
Multiwall Carbon Nanotube ◽  
Solution Processed ◽  
Electrical Percolation ◽  
Turn On ◽  
Electrical Percolation Threshold ◽  
Near Future

Carbon nanotubes have been the subject of extensive research during the past decade because of their exceptional properties. These tiny nanostructures have eventually paved their way into the exciting and promising field of organic electronics, which is expected to dominate the area of low cost and flexible electronics in the near future. We have prepared multiwall carbon nanotube (MWNT) and poly(3,4-ethylenedioxythiophene):poly(styrenesulphonic acid) (PEDOT:PSS) based nanocomposites using different concentrations of MWNTs. These nanocomposites have been characterized using SEM, AFM, absorption spectroscopy, and electrical characterization methods. The SEM micrographs clearly reveal that the nanotubes are quasi uniformly dispersed in huge quantities throughout the polymer matrix. They also show the wetting of the nanotubes by the polymer. It is observed that the solution processed MWNT–PEDOT:PSS nanocomposite based films exhibit improved, higher current, and lower turn-on voltage as compared to pure PEDOT:PSS based films. On the basis of percolation theory, a low electrical percolation threshold value of 0.1 wt% was obtained for this nanocomposite system, signifying the formation of a continuous conductive network at a very low MWNT concentration. The ease of fabrication of the nanocomposite (solution processed), higher current, lower turn-on voltage and low electrical percolation threshold value, make it an excellent candidate for flexible electronics applications, which will dominate the electronics scenario in the near future.

Electrical conductivity and rheological properties of carbon black based conductive polymer composites prior to and after annealing

2021 ◽  
pp. 096739112110012
Author(s):  
Qingsen Gao ◽  
Jingguang Liu ◽  
Xianhu Liu
Keyword(s):  
Electrical Conductivity ◽  
Carbon Black ◽  
Percolation Threshold ◽  
Rheological Properties ◽  
Network Formation ◽  
Loss Modulus ◽  
Conductive Polymer ◽  
Complex Viscosity ◽  
Electrical Percolation ◽  
Electrical Percolation Threshold

The effect of annealing on the electrical and rheological properties of polymer (poly (methyl methacrylate) (PMMA) and polystyrene (PS)) composites filled with carbon black (CB) was investigated. For a composite with CB content near the electrical percolation threshold, the formation of conductive pathways during annealing has a significant impact on electrical conductivity, complex viscosity, storage modulus and loss modulus. For the annealed samples, a reduction in the electrical and rheological percolation threshold was observed. Moreover, a simple model is proposed to explain these behaviors. This finding emphasizes the differences in network formation with respect to electrical or rheological properties as both properties belong to different physical origins.

A promising approach to low electrical percolation threshold in PMMA nanocomposites by using MWCNT-PEO predispersions

2016 ◽  
Vol 111 ◽  
pp. 253-262 ◽  
Author(s):  
Seyed Mohammad Mir ◽  
Seyed Hassan Jafari ◽  
Hossein Ali Khonakdar ◽  
Beate Krause ◽  
Petra Pötschke ◽  
...  
Keyword(s):  
Percolation Threshold ◽  
Electrical Percolation ◽  
Electrical Percolation Threshold

scholarly journals Broadband Dielectric Properties of Fe2O3·H2O Nanorods/Epoxy Resin Composites

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Darya Meisak ◽  
Jan Macutkevic ◽  
Dzmitry Bychanok ◽  
Algirdas Selskis ◽  
Juras Banys ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Percolation Threshold ◽  
Epoxy Resin ◽  
Polymer Matrix ◽  
Finite Conductivity ◽  
Resin Composites ◽  
Electrical Percolation ◽  
Electrical Percolation Threshold ◽  
Percolation Network ◽  
Properties Of Composites

A series of polymer composites based on epoxy resin with a 5–40 vol.% concentration of goethite (Fe2O3·H2O) nanorods was produced. The electrical percolation threshold in these composites was determined as 30 vol.% of nanorods. The dielectric properties of the composites both below and above the percolation threshold were studied in a wide temperature (200 K–450 K) and frequency (from Hz to THz) ranges. The dielectric properties of composites below the percolation threshold are mainly determined by the relaxation in a pure polymer matrix. The electrical properties of composites above the percolation threshold are determined by the percolation network, which is formed by the goethite nanorods inside the polymer matrix. Due to the finite conductivity of the epoxy resin, the electrical conductivity at high temperatures occurs in the composites both above and below the percolation threshold.

scholarly journals A Numerical Study on Electrical Percolation of Polymer-Matrix Composites with Hybrid Fillers of Carbon Nanotubes and Carbon Black

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yuli Chen ◽  
Shengtao Wang ◽  
Fei Pan ◽  
Jianyu Zhang
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Black ◽  
Percolation Threshold ◽  
Polymer Matrix ◽  
Polymer Matrix Composites ◽  
Matrix Composites ◽  
Electrical Percolation ◽  
Hybrid Fillers ◽  
Nonlinear Relation ◽  
Electrical Percolation Threshold

The electrical percolation of polymer-matrix composites (PMCs) containing hybrid fillers of carbon nanotubes (CNTs) and carbon black (CB) is estimated by studying the connection possibility of the fillers using Monte Carlo simulation. The 3D simulation model of CB-CNT hybrid filler is established, in which CNTs are modeled by slender capped cylinders and CB groups are modeled by hypothetical spheres with interspaces because CB particles are always agglomerated. The observation on the effects of CB and CNT volume fractions and dimensions on the electrical percolation threshold of hybrid filled composites is then carried out. It is found that the composite electrical percolation threshold can be reduced by increasing CNT aspect ratio, as well as increasing the diameter ratio of CB groups to CNTs. And adding CB into CNT composites can decrease the CNT volume needed to convert the composite conductivity, especially when the CNT volume fraction is close to the threshold of PMCs with only CNT filler. Different from previous linear assumption, the nonlinear relation between CB and CNT volume fractions at composite percolation threshold is revealed, which is consistent with the synergistic effect observed in experiments. Based on the nonlinear relation, the estimating equation for the electrical percolation threshold of the PMCs containing CB-CNT hybrid fillers is established.

Qualitative Equivalence Between Electrical Percolation Threshold and Effective Thermal Conductivity in Polymer/Carbon Nanocomposites

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Majid Baniassadi ◽  
Akbar Ghazavizadeh ◽  
Yves Rémond ◽  
Said Ahzi ◽  
David Ruch ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Percolation Threshold ◽  
Effective Thermal Conductivity ◽  
Electrical Percolation ◽  
Aspect Ratios ◽  
Wide Range ◽  
Statistical Continuum ◽  
Electrical Percolation Threshold

In this study, a qualitative equivalence between the electrical percolation threshold and the effective thermal conductivity of composites filled with cylindrical nanofillers has been recognized. The two properties are qualitatively compared on a wide range of aspect ratios, from thin nanoplatelets to long nanotubes. Statistical continuum theory of strong-contrast is utilized to estimate the thermal conductivity of this type of heterogeneous medium, while the percolation threshold is simultaneously evaluated using the Monte Carlo simulations. Statistical two-point probability distribution functions are used as microstructure descriptors for implementing the statistical continuum approach. Monte Carlo simulations are carried out for calculating the two-point correlation functions of computer generated microstructures. Finally, the similarities between the effective conductivity properties and percolation threshold are discussed.

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