The growth in the application of electronic devices across a broad spectrum of military, industrial, commercial and consumer sectors has created a new form of pollution known as noise or radio frequency interference (RFI) or electromagnetic radiation or electromagnetic interference (EMI) that can cause interference or malfunctioning of equipment. Therefore, there is a greater need for the effective shielding of components from its adverse effects. This review surveys the shielding materials like metals, conducting plastics and conducting polymers for the control of electromagnetic radiations. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

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EMI shielding: Methods and materials—A review

This paper summarizes and reviews the research on electromagnetic interference (EMI) shielding with intrinsically conducting polymers (ICPs), mainly polyaniline (PANI) and polypyrrole (PPY), and their composites in various frequency ranges. ICPs are new alternative candidates for EMI shielding applications due to their lightweight, corrosion resistance, ease of processing, and tunable conductivities as compared with typical metals. More importantly, the dominant shielding characteristic of absorption other than that of reflection for metals render ICPs more promising materials in applications requiring not only high EMI shielding effectiveness but also shielding by absorption, such as in stealth technology. Copyright © 2005 John Wiley & Sons, Ltd.

Intrinsically conducting polymers for electromagnetic interference shielding

Some aspects of preparation methods and properties of polyaniline blends and composites with organic polymers

A paradigm shift takes place in the fabrication of conducting polymers from bulky features with microsize to ultrafine features with nanometer range. Novel conducting polymer nanomaterials require the potential to control synthetic approaches of conducting polymer on molecular and atomic levels. In this article, the synthetic methodology of conducting polymer has been briefly considered with chemical oxidation polymerization and electrochemical polymerization. The recent achievements in the fabrication of conducting polymer nanomaterials have been extensively reviewed with respect to soft template method, hard template method and template-free method. It also details the morphological spectrum of conducting polymer nanomaterials such as nanoparticle, core-shell nanomaterial, hollow nanosphere, nanofiber/nanorod, nanotube, thin film and nanopattern and nanocomposite. In addition, their applications are discussed under nanometer-sized dimension.

Conducting polymer nanomaterials and their applications

A polyaniline/polystyrene composite film with a lotus-leaf-like structure is prepared via a simple electrospinning method. The film shows stable superhydrophobicity and conductivity, even in many corrosive solutions, such as acidic or basic solutions over a wide pH range, and also in oxidizing solutions. The special surface composition and morphology are the two important aspects that induce such unusual properties. The polystyrene content can strongly influence the morphology of the composite films, which thus display different superhydrophobicities and conductivities.

Stable, Superhydrophobic, and Conductive Polyaniline/Polystyrene Films for Corrosive Environments

Polyaniline-poly(vinyl alcohol) conducting composite : material with easy processability and novel application potential

The current paper presents a novel and unique scheme for biomedical image watermarking in wavelet domain by hiding multiple copies of the same data in the cover image using bit replacement in the horizontal (HL) and vertical (LH) resolution approximation image components. The proposed scheme uses an approach for recovering the hidden information from the damaged copies due to unauthorized alteration of the data by applying an algorithm to find the closest twin of the embedded information by bit majority algorithm. Experimental results of the proposed watermarking technique show much enhancement in the visual and statistical invisibility of hidden information after data recovery that supports the improvement in performance.

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Biomedical Image Watermarking in Wavelet Domain for Data Integrity Using Bit Majority Algorithm and Multiple Copies of Hidden Information

Recent history has witnessed the rapid development in information technologies that has given an extended and easy access to digital information Along with several developments it leads to the problem of illegal copying and redistribution of digital media As a result the integrity and confidentiality of the digital information has come under immense threat The concept of an emerging technology, digital watermarking came in order to solve the problems related to the intellectual property of media (PWWong, 1998) Digital Watermarking is a technique which allows an individual to add hidden copyright notices or other verification messages or even classified information to digital media (Rafael C Gonzalez and Richard E Woods, 2002), (Cox I J, Miller M, Bloom J, 2002)

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A Novel Digital Image Watermarking Scheme for Data Security Using Bit Replacement and Majority Algorithm Technique

The current paper presents a new digital watermarking method through bit replacement technology, which stores mul-tiple copies of the same data that is to be hidden in a scrambled form in the cover image. In this paper an indigenous approach is described for recovering the data from the damaged copies of the data under attack by applying a majority algorithm to find the closest twin of the embedded information. A new type of non-oblivious detection method is also proposed. The improvement in performance is supported through experimental results which show much enhancement in the visual and statistical invisibility of hidden data.

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Reversible Digital Image Watermarking Scheme Using Bit Replacement and Majority Algorithm Technique

The current paper proposes a biomedical image watermarking technique through modified bit replacement algorithm in spatial domain. In this algorithm, multiple copies of the same information are hidden in the biomedical images. Detection is performed by applying bit majority algorithm which can reconstruct the hidden information from different recovered sets subjected to some common attacks. Keys for watermark recovery are also embedded in the cover image. The superiority of the proposed modified bit replacement scheme over the LSB technique is indicated through evaluation of image quality metrics that shows much enhancement in the visual and statistical invisibility of hidden data.

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Goutam Ghosh

Papers

Polyaniline-poly(vinyl alcohol) conducting composite : material with easy processability and novel application potential

Biomedical Image Watermarking in Wavelet Domain for Data Integrity Using Bit Majority Algorithm and Multiple Copies of Hidden Information

A Novel Digital Image Watermarking Scheme for Data Security Using Bit Replacement and Majority Algorithm Technique

Reversible Digital Image Watermarking Scheme Using Bit Replacement and Majority Algorithm Technique

A Comparative Study between LSB and Modified Bit Replacement (MBR) Watermarking Technique in Spatial Domain for Biomedical Image Security