Discover Top Posts Tagged with #polyaniline

Conductive polymers: First successful synthesis of polyaniline with golden luster

Researchers at the University of Tsukuba, Japan, have developed a method for synthesizing polyaniline—a conductive polymer exhibiting golden luster—marking the first successful attempt globally. The reflection spectrum of this polyaniline resembles that of metallic gold. Polyaniline, a conductive polymer typically synthesized in water and appears dark green, exhibits different properties based on its synthesis and processing conditions. The research team involved in the study, now published in Next Materials, successfully synthesized polyaniline, with golden luster, in two stages. In the first stage, fine particles were prepared using short-time electrochemical polymerization, high-voltage spark treatment and other methods, and in the second stage, chemical polymerization was applied. Notably, the electrical conductivity of this golden polyaniline is lower than that of polyacetylene, making it unsuitable for transmitting large currents. However, this golden polyaniline has the potential to revolutionize the electronics sector due to its applicability in micro-organic semiconductor thin-films and other similar devices.

New conductive, cotton-based fiber developed for smart textiles

A single strand of fiber developed at Washington State University has the flexibility of cotton and the electric conductivity of a polymer, called polyaniline. The newly developed material showed good potential for wearable e-textiles. The WSU researchers tested the fibers with a system that powered an LED light and another that sensed ammonia gas, detailing their findings in the journal Carbohydrate Polymers. "We have one fiber in two sections: one section is the conventional cotton: flexible and strong enough for everyday use, and the other side is the conductive material," said Hang Liu, WSU textile researcher and the study's corresponding author. "The cotton can support the conductive material which can provide the needed function."

Electrically conductive paints and other polymer alloys now produced easily

Medical devices, cars, and many advanced technologies contain innumerable delicate components that are held together by electrically conductive polymers, such as polyaniline. For several decades, synthesis of polyaniline for industrial electronics applications has faced a major limitation: what solvent best facilitates synthesis? This abstract question is important for minimizing the cost and complexity of polyaniline production and facilitating useful properties such as shaping. The ability to use a range of cheap, low-boiling-point solvents would greatly assist versatile polymer processing modes such as inkjet printing, but had remained elusive until now.

In a study recently published in Polymer-Plastics Technology and Materials, researchers from the University of Tsukuba and collaborating partners have synthesized polyaniline in various common solvents. This improved ability to synthesize and process polyaniline will greatly simplify production and lower manufacturing costs.

"Polyaniline is an extremely versatile polymer in routine and advanced technologies, but restrictions on which solvents can be used for synthesis have long hindered this versatility," explains Professor Hiromasa Goto, senior author. "Our discovery of how to facilitate polymerization in diverse solvents will be useful in basic research and industrial applications."

Stronger than spider silk: Bagworm silk enables strong conducting fibers

Think spider silk is strong? Recent work has shown that bagworm silk is superior to spider silk in both strength and flexibility. Building on these findings, a research team at the University of Tsukuba, led by Professor Hiromasa Goto, has harnessed the strength of bagworm silk to produce a strong, flexible, conductive fiber. This research may lead to new flexible electronic devices, such as wearable electronic materials.

Owing to its high flexibility and strength, spider silk has received much attention for uses ranging from medicine to aerospace applications. By combining natural silk, such as spider silk, with synthetic conductive polymers, researchers can produce textiles with conduction, light emission, and photovoltaic functions. It is also possible to create biocompatible materials that can be used in regenerative medicine and biomedical materials. "We've taken the next step from previous research efforts by utilizing the strongest known natural fiber—bagworm silk," explains Professor Goto.

In this study, the research team combined polyaniline, a conducting polymer that can be easily synthesized, with bagworm silk obtained from a bagworm nest. The composite fibers obtained from the silk and polyaniline were 2 microns in diameter and acted as optical waveguides. The investigators demonstrated that green laser light propagates along these fibers, while remaining confined within each fiber. To determine the magnetic properties of the material, the investigators performed superconducting interference device (SQUID) measurements. The results revealed that the composite fibers can act as paramagnets: the fibers become magnetized when placed in an external magnetic field. By applying the bagworm silk/polyaniline composite in a field-effect transistor device, the research team also confirmed that the composite fiber is suitable for use in textile transistors.

Surrey unveils fast-charging super-capacitor technology

Experts from the University of Surrey believe their dream of clean energy storage is a step closer after they unveiled their ground-breaking super-capacitor technology that is able to store and deliver electricity at high power rates, particularly for mobile applications.

In a paper published by the journal Energy and Environmental Materials, researchers from Surrey's Advanced Technology Institute (ATI) revealed their new technology which has the potential to revolutionize energy use in electric vehicles and reduce renewable based energy loss in the national grid. The team also believe their technology can help push forward the advancement of wind, wave and solar energy by smoothing out the intermittent nature of the energy sources.

The ATI's super-capacitor technology is based on a material called Polyaniline (PANI), which stores energy through a mechanism known as "pseudocapacitance." This cheap polymer material is conductive and can be used as the electrode in a super-capacitor device. The electrode stores charge by trapping ions within the electrode. It does this by exchanging electrons with the ion, which "dopes" the material.

New 'supercondensers' store electric charge in textile materials

Researchers of the Alcoi campus of Valencia's Polytechnic University (UPV) have developed new devices that store electric charge in textile materials, which could be used to, for example, charge our mobile phone. They are supercondensers placed on active carbon tissues that stand out due to their electric properties and high level of power. Their work has been published in the European Polymer Journal.

The study was focused on using textile materials as electrodes. In this case, the devices they have designed and tested make use of all the potential of active carbon, graphene and polyaniline, a polymer with high capabilities that is already broadly used in textile materials.

From their laboratories in the Alcoi campus, they evaluated different strategies that obtain electric charge accumulators from the electrochemical reduction of graphene oxide on the surface of the activated carbon (reduced graphene oxide—RGO) and the subsequent electrosynthesis of polyaniline (Pani).

"We have obtained new electric charge accumulators with specific power that are very competitive, and which could be used to charge the batteries of several devices. The supercondensers have been developed on textile materials, and therefore, the volume/mass and surface/mass ratios are very high. Hence their great potential. And as textile materials, these supercondensers could be small to supply energy to mobile devices, from our mobile phone, to a tablet or laptop, to name a few examples," says Francisco J. Cases, head of the GESEP.

Smallest pixels ever created could light up color-changing buildings

The smallest pixels yet created -- a million times smaller than those in smartphones, made by trapping particles of light under tiny rocks of gold -- could be used for new types of large-scale flexible displays, big enough to cover entire buildings.

The colour pixels, developed by a team of scientists led by the University of Cambridge, are compatible with roll-to-roll fabrication on flexible plastic films, dramatically reducing their production cost. The results are reported in the journal Science Advances.

It has been a long-held dream to mimic the colour-changing skin of octopus or squid, allowing people or objects to disappear into the natural background, but making large-area flexible display screens is still prohibitively expensive because they are constructed from highly precise multiple layers.

At the centre of the pixels developed by the Cambridge scientists is a tiny particle of gold a few billionths of a metre across. The grain sits on top of a reflective surface, trapping light in the gap in between. Surrounding each grain is a thin sticky coating which changes chemically when electrically switched, causing the pixel to change colour across the spectrum.