scholarly journals Non-universal scaling behavior of polymer-metal composites across the percolation threshold

2015 ◽  
Vol 5 ◽  
pp. 136-141 ◽  
Author(s):  
Maheswar Panda ◽  
V. Srinivas ◽  
A.K. Thakur
Keyword(s):  
Percolation Threshold ◽  
Scaling Behavior ◽  
Metal Composites ◽  
Universal Scaling ◽  
Polymer Metal

Universal scaling behavior of polymer chains at the percolation threshold

Soft Matter ◽  
2018 ◽  
Vol 14 (41) ◽  
pp. 8249-8252 ◽  
Author(s):  
Piotr Polanowski ◽  
Andrzej Sikorski
Keyword(s):  
Percolation Threshold ◽  
Scaling Behavior ◽  
Polymer Chains ◽  
Universal Scaling

A universal scaling behavior of chain size at the percolation threshold is presented.

scholarly journals Frequency-dependent scaling behavior of polyvinylidene fluoride/metal composites

2019 ◽  
Vol 09 (02) ◽  
pp. 1950010
Author(s):  
Maheswar Panda
Keyword(s):  
Polyvinylidene Fluoride ◽  
Dielectric Constants ◽  
Scaling Behavior ◽  
Process Conditions ◽  
Polarization Model ◽  
Metal Composites ◽  
Frequency Dependent ◽  
Alloy Particles ◽  
Polymer Metal ◽  
Experimental Values

The frequency-dependent percolation and scaling behavior of a variety of polymer/metal composites (PMC), based on polyvinylidene fluoride (PVDF) matrix and various types of fillers such as; metal/alloy particles of different sizes, prepared through cold/hot pressing process conditions have undergone investigation. The universal percolation behavior in the vicinity of percolation threshold ([Formula: see text]), i.e., [Formula: see text] and [Formula: see text] is well satisfied, which suggests [Formula: see text] to be independent of frequency, where [Formula: see text] and [Formula: see text] are the effective ac conductivity and effective dielectric constants of the composite and [Formula: see text] is the frequency of applied ac signal. The obtained experimental values of the exponents are consistent with the inter-cluster polarization model ([Formula: see text] and [Formula: see text]), satisfying [Formula: see text]. The widely used percolative equations are well fitted with the experimental results of all PMC at all values of the frequency. The value of [Formula: see text] is found to be independent of frequency of the applied signal, suggesting the studied PMC are real percolating systems. The critical exponents ([Formula: see text] and [Formula: see text]) which characterize the divergence of [Formula: see text] and [Formula: see text] in the vicinity of [Formula: see text] are found to decrease with the increase of frequency. The rate of decrease of ‘[Formula: see text]’ and ‘[Formula: see text]’ with increase of frequency is attributed to the method of preparation, size of the fillers, adhesiveness of polymer/filler and the rate of decrease of [Formula: see text] with frequency (due to the absence of different extents of contributions of various types of conventional polarizations).

scholarly journals Dielectric spectroscopy of polymer-metal composites across the percolation threshold

2014 ◽  
Vol 04 (04) ◽  
pp. 1450027 ◽  
Author(s):  
Maheswar Panda ◽  
V. Srinivas ◽  
A. K. Thakur
Keyword(s):  
Percolation Threshold ◽  
Volume Fraction ◽  
Strong Dependence ◽  
Low Frequency ◽  
Frequency Dispersion ◽  
Process Conditions ◽  
Predominant Role ◽  
Dipolar Relaxation ◽  
Metal Composites ◽  
Polymer Metal

Polymer (polar/nonpolar)/metal composites (PMC) were prepared under different process conditions. In polar PMC, dipolar relaxation plays a predominant role below percolation threshold (fc) and anomalous low frequency dispersion (ALFD) becomes dominant above fc while ALFD is the only likely possibility for nonpolar PMC above fc. The magnitude of relaxation exponents "m", "p" and "n", evaluated from the experimental results using Jonscher's universal dielectric response (JUDR) laws, falls within the universal limit ~ [0, 1] with additional feature of strong dependence on volume fraction of conductor (f con ). The decrease in the relaxation exponent "m" with an increase of f con is directly linked with decrease in the number of dipoles of the polymer in the composite and is accompanied by a distribution of relaxation time due to increased heterogeneity of the system. The magnitude of the relaxation exponent "n" decreases at fc, due to the prevalence of Maxwell–Wagner–Sillar polarization contributed by uncorrelated electrons.

Geometry-based, n-type-enhanced p-type polymer/metal oxide nanocomposites for high-efficiency, high-specificity conductive systems

2014 ◽  
Vol 1630 ◽  
Author(s):  
Riccardo Raccis ◽  
Laura Wortmann ◽  
Shaista Ilyas ◽  
Johannes Schläfer ◽  
Andreas Mettenbörger ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Percolation Threshold ◽  
High Efficiency ◽  
High Specificity ◽  
Data Fitting ◽  
Basic Properties ◽  
Frenkel Effect ◽  
Polymer Metal ◽  
Different Shapes ◽  
P Type

ABSTRACTHematite (α-Fe2O3) nanoparticles were diffused of two different shapes (spherical and cubical) in PEDOT:PSS matrices below the percolation threshold. Increases in conductivity within a distinct range in concentration were observed in the dark and under simulated solar illumination. The effect was ascribed to a generalized Poole-Frenkel effect in conjunction with basic properties of heterojunctions and electrostatic dipoles, and verified through data fitting. A difference in behaviour between sphere- and cube-based nanocomposites was also observed.

An IPMC Actuated 3D Swimming Microrobot and its Propulsive Efficiency Analysis

2009 ◽  
Vol 419-420 ◽  
pp. 785-788
Author(s):  
Xiu Fen Ye ◽  
Yu Dong Su ◽  
Shu Xiang Guo
Keyword(s):  
Autonomous Navigation ◽  
Water Electrolysis ◽  
Efficiency Analysis ◽  
Infrared Sensors ◽  
Metal Composites ◽  
Propulsive Efficiency ◽  
Ionic Polymer Metal Composites ◽  
Ionic Polymer ◽  
Wireless Control ◽  
Polymer Metal

An Ionic polymer metal composites (IPMC) actuated 3D swimming microrobot is presented first. Inspired by biologic fins, passive plastic fin is attached to the IPMC strip to increase the thrust. Infrared sensors are equipped for wireless control and autonomous navigation. Then propulsive efficiency analyses are carried out. From the water electrolysis influence analysis of the IPMC, the best working voltage is confirmed. Finally, a two parts IPMC actuator is presented to improve the propulsive efficiency of the microrobot after the analysis of propulsive efficiency of caudal fin.

Biomimetic Applications of Ionic Polymer Metal Composites (IPMC) Actuators - A Critical Review

2014 ◽  
Vol 20 ◽  
pp. 1-10 ◽  
Author(s):  
Muhammad Farid ◽  
Zhao Gang ◽  
Tran Linh Khuong ◽  
Zhuang Zhi Sun ◽  
Naveed Ur Rehman ◽  
...  
Keyword(s):  
Critical Review ◽  
Low Voltage ◽  
Metal Composite ◽  
Ionic Polymer Metal Composite ◽  
Metal Composites ◽  
Ionic Polymer Metal Composites ◽  
Ionic Polymer ◽  
Design And Manufacturing ◽  
Polymer Metal ◽  
Biomedical Field

Biomimetic is the field of engineering in which biological creatures and their functions are investigated and are used as the basis for the design and manufacturing of machines. Ionic Polymer Metal Composite (IPMC) is a smart material which has demonstrated a meaningful bending and tip force after the application of a low voltage. It is light-weighted, flexible, easily actuated, multi-directional applicable and requires simple manufacturing. Resultantly, IPMC has attracted scientists and researchers to analyze it further and consider it for any industrial and biomimetic applications. Presently, the research on IPMC is bi-directional oriented. A few groups of researchers are busy to find out the causes for the weaknesses of the material and to find out any remedy for them. The second class of scientists is exploring new areas of applications where IPMC material can be used. Although, the application zone of IPMC is ranging from micropumps diaphragms to surgical holding devices, this paper provides an overview of the IPMC application in biomimetic and biomedical field.

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