Electrical percolation in extrinsically conducting, poly(ε-decalactone) composite neural interface materials

AbstractBy providing a bidirectional communication channel between neural tissues and a biomedical device, it is envisaged that neural interfaces will be fundamental in the future diagnosis and treatment of neurological disorders. Due to the mechanical mismatch between neural tissue and metallic neural electrodes, soft electrically conducting materials are of great benefit in promoting chronic device functionality. In this study, carbon nanotubes (CNT), silver nanowires (AgNW) and poly(hydroxymethyl 3,4-ethylenedioxythiophene) microspheres (MSP) were employed as conducting fillers within a poly(ε-decalactone) (EDL) matrix, to form a soft and electrically conducting composite. The effect of a filler type on the electrical percolation threshold, and composite biocompatibility was investigated in vitro. EDL-based composites exhibited favourable electrochemical characteristics: EDL/CNT—the lowest film resistance (1.2 ± 0.3 kΩ), EDL/AgNW—the highest charge storage capacity (10.7 ± 0.3 mC cm− 2), and EDL/MSP—the highest interphase capacitance (1478.4 ± 92.4 µF cm−2). All investigated composite surfaces were found to be biocompatible, and to reduce the presence of reactive astrocytes relative to control electrodes. The results of this work clearly demonstrated the ability of high aspect ratio structures to form an extended percolation network within a polyester matrix, resulting in the formulation of composites with advantageous mechanical, electrochemical and biocompatibility properties.

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Effect of Mixing Parameter on Electrical Conductivity of Carbon Black/Graphite/Epoxy Nanocomposite Using Taguchi Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.393.68 ◽

2013 ◽

Vol 393 ◽

pp. 68-73 ◽

Cited By ~ 2

Author(s):

Mohd Yusuf Zakaria ◽

Hendra Suherman ◽

Jaafar Sahari ◽

Abu Bakar Sulong

Keyword(s):

Electrical Conductivity ◽

Electrical Properties ◽

Carbon Black ◽

Polymer Composite ◽

Low Cost ◽

Conducting Phase ◽

Electrical Percolation ◽

Electrically Conducting ◽

Conducting Materials ◽

Mixing Parameter

Polymer composite has attracted many researchers from various field of application due to its unique features and properties including light weight, low cost, ease to process and shaping and corrosion resistant [1-3]. Fillers is typically added to enhance the chemical and physical properties of polymers [4, 5]. One of the properties is the electrical conductivity. Carbon based filler such as graphite (G), carbon black (CB), carbon fibers (CF) and carbon nanotubes (CNT) has been extensively used to improve electrical properties of polymer composite [6-8]. Electrical properties of the composite can be explained from percolation theory which means electrical percolation in mixtures of electrically conducting and non-conducting materials [9]. The concentration of conducting phase must above the critical value called percolation threshold, in order for the material become electrically conductive [10].

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Influence of Carbon Nanotube-Pretreatment on the Properties of Polydimethylsiloxane/Carbon Nanotube-Nanocomposites

Polymers ◽

10.3390/polym13091355 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1355

Author(s):

Astrid Diekmann ◽

Marvin C. V. Omelan ◽

Ulrich Giese

Keyword(s):

Electrical Conductivity ◽

Carbon Nanotube ◽

Mechanical Performance ◽

Softening Effect ◽

Electrical Percolation ◽

Optimum Parameters ◽

Lauryl Ether ◽

Solvent Residues ◽

Electrical Percolation Threshold ◽

Filler Dispersion

Incorporating nanofillers into elastomers leads to composites with an enormous potential regarding their properties. Unfortunately, nanofillers tend to form agglomerates inhibiting adequate filler dispersion. Therefore, different carbon nanotube (CNT) pretreatment methods were analyzed in this study to enhance the filler dispersion in polydimethylsiloxane (PDMS)/CNT-composites. By pre-dispersing CNTs in solvents an increase in electrical conductivity could be observed within the sequence of tetrahydrofuran (THF) > acetone > chloroform. Optimization of the pre-dispersion step results in an AC conductivity of 3.2 × 10−4 S/cm at 1 Hz and 0.5 wt.% of CNTs and the electrical percolation threshold is decreased to 0.1 wt.% of CNTs. Optimum parameters imply the use of an ultrasonic finger for 60 min in THF. However, solvent residues cause a softening effect deteriorating the mechanical performance of these composites. Concerning the pretreatment of CNTs by physical functionalization, the use of surfactants (sodium dodecylbenzenesulfonate (SDBS) and polyoxyethylene lauryl ether (“Brij35”)) leads to no improvement, neither in electrical conductivity nor in mechanical properties. Chemical functionalization enhances the compatibility of PDMS and CNT but damages the carbon nanotubes due to the oxidation process so that the improvement in conductivity and reinforcement is superimposed by the CNT damage even for mild oxidation conditions.

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

Polymers and Polymer Composites ◽

10.1177/09673911211001277 ◽

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.

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Effective Doping of Single-Walled Carbon Nanotubes with Polyethyleneimine

Materials ◽

10.3390/ma14010065 ◽

2020 ◽

Vol 14 (1) ◽

pp. 65

Author(s):

Monika Rdest ◽

Dawid Janas

Keyword(s):

Carbon Nanotubes ◽

Technological Progress ◽

Single Walled Carbon Nanotubes ◽

Performance Limits ◽

Operational Parameters ◽

Single Walled Carbon ◽

Electrically Conducting ◽

Conducting Materials ◽

Walled Carbon Nanotubes ◽

Synthesis Stage

More and more electrically conducting materials are required to sustain the technological progress of civilization. Faced with the performance limits of classical materials, the R&D community has put efforts into developing nanomaterials, which can offer sufficiently high operational parameters. In this work, single-walled carbon nanotubes (SWCNTs) were doped with polyethyleneimine (PEI) to create such material. The results show that it is most fruitful to combine these components at the synthesis stage of an SWCNT network from their dispersion. In this case, the electrical conductivity of the material is boosted from 249 ± 21 S/cm to 1301 ± 56 S/cm straightforwardly and effectively.

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Experimental Investigation of Morphological and Electrical Characteristics of PS/MWCNT Nanocomposite Films

Materials Science Forum ◽

10.4028/www.scientific.net/msf.915.104 ◽

2018 ◽

Vol 915 ◽

pp. 104-109

Author(s):

Barış Demirbay ◽

Şaziye Uğur

Keyword(s):

Annealed Film ◽

Nanocomposite Films ◽

Electrical Characteristics ◽

Liquid Form ◽

Mwcnt Content ◽

Electrical Percolation ◽

Glass Substrates ◽

Multi Walled Carbon Nanotubes ◽

Electrical Percolation Threshold ◽

Walled Carbon Nanotubes

Electrical characteristics and morphology of nanocomposite films composed of two different polystyrene (PS) latexes impregnated with multi-walled carbon nanotubes (MWCNT) in the range between 0 wt% and 20 wt% were assessed by considering photon transmission (UV-Vis) technique and electrical conductivity measurements. Emulsion polymerization technique was employed both to synthesize very fine PS particles dispersed in water and to tailor the sizes of the PS particles as 382 nm and 560 nm, respectively. PS/MWCNT nanocomposite films were obtained from the liquid form on glass substrates via drop-casting method and all they dried at 40 QUOTE C. Each dried sample was then annealed at varying temperatures between 100 QUOTE C and 250 QUOTE C for 10 min. The surface conductivity QUOTE of each annealed film at 250 QUOTE C was measured and was found to increase dramatically above a certain mass fraction of MWCNT content, QUOTE . Each set of PS/MWCNT nanocomposite film had a similar electrical percolation threshold of QUOTE =1.5 wt% as the MWCNT content and critical exponents of QUOTE were found to be 2.64 and 1.19 for 382 nm and 560 nm PS latex systems, respectively.

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