Research/development, chemical sensors

The development of AW thin-film characterization techniques has occurred largely because of the interest by various research groups in developing chemical sensors based on coated AW devices (see Chapter 5). Thus, many of the film characterization techniques described here were developed in an effort to characterize sensor coatings or to interpret the observed responses from AW chemical sensors in operation. 

Our research on chemical sensors and electronic noses is supported by grants from the Swedish National Board for Technical and Industrial Development, the Swedish Engineering Sciences Research Council and the Center for Industrial Information Technology at Linkdping University. 

The researchers of the National Centre for Sensor Research, Dublin City University (Ireland), developed chemical sensors able to measure and analyze sweat in real time on the body. They designed a microchip version of the platform to measure changes in the pH of sweat. The color change of the pH sensitive fabric was detected by placing a surface mount LED and photodiode module on either side of the chip, aligned with the pH sensitive fabric. The final device (180 pm thick) is flexible and can adapt to the body (Benito-Lopez et al., 2009). 

The development of highly selective chemical sensors for complex matrixes of medical, environmental, and industrial interest has been the object of greate research efforts in the last years. Recently, the use of artificial materials - molecularly imprinted polymers (MIPs) - with high recognition properties has been proposed for designing biomimetic sensors, but only a few sensor applications of MIPs based on electrosynythesized conductive polymers (MIEPs) have been reported [1-3]. 

Even listing all above problems and requirements leading to their solution indicates that development of the method of semiconductor chemical sensors opens a wide research domain. In order to resolve this problems and implement all capabilities of the method of semiconductor sensors there are two ways now the old trial and error approach and approach related to further studies of physical and chemical properties of surface phenomena, reactions and processes underlying this method. It is quite clear that the second approach is more promising in order to obtain semiconductor sensors designed for the use in accurate scientific studies and for practical gas analysis. 

In biomedicine, an important field of research is the one associated with the development of sensors for the detection of physical and chemical parameters in the human body. 

A number of optical chemical sensor systems have been developed for food and packaging applications and proven their utility. Some sensors, such as phase-fluorimetric oxygen sensor, have already reached high degree of maturity and demonstrated their potential for use on a mass scale. While the others still require extensive research, development and search for new solutions, so as to match basic practical requirements for such sensors. The experience and lessons learned with current optical sensor systems must be... 

The goal of this book is to cover the full scope of electrochemical sensors and biosensors. It offers a survey of the principles, design and biomedical applications of the most popular types of electrochemical devices in use today. The book is aimed at all scientists and engineers who are interested in developing and using chemical sensors and biosensors. By discussing recent advances, it is hoped to bridge the common gap between research literature and standard textbooks. 

Dr. Hui has worked on various projects, including chemical sensors, solid oxide fuel cells, magnetic materials, gas separation membranes, nanostruc-tured materials, thin film fabrication, and protective coatings for metals. He has more than 80 research publications, one worldwide patent, and one U.S. patent (pending). He is currently leading and involved in several projects for the development of metal-supported solid oxide fuel cells (SOFCs), ceramic nanomaterials as catalyst supports for high-temperature PEM fuel cells, protective ceramic coatings on metallic substrates, ceramic electrode materials for batteries, and ceramic proton conductors. Dr. Hui is also an active member of the Electrochemical Society and the American Ceramic Society. 

An excihng new scientific direction emerged in the 1980s and 1990s for exploring molecular sieves as advanced solid state materials. In a 1989 review, Ozin et al. [88] speculated that zeolites (molecular sieves) as microporous molecular electronic materials with nanometer dimension window, channel and cavity architecture represent a new fronher of solid state chemistry with great opportunihes for innovahve research and development . The applicahons described or envisioned included molecular electronics, quantum dots/chains, zeolite electrodes, batteries, non-linear ophcal materials and chemical sensors. More recently there have been significant research reports on the use of zeolites as low k dielectric materials for microprocessors [89]. 

The first report of surface-immobilized dendrimers was in 1994 [54]. Subsequently, our research group showed that the amine-terminated PAMAM and PPl dendrimers could be attached to an activated mercaptoimdecanoic acid (MUA) self-assembled monolayer (SAM) via covalent amide linkages [55, 56]. Others developed alternative surface immobilization strategies involving metal com-plexation [10] and electrostatic binding [57]. These surface-confined dendrimer monolayers and multilayers have found use as chemical sensors, stationary phases in chromatography, and catalytic interfaces [41,56,58,59]. Additional applications for surface-confined dendrimers are inevitable, and are dependent only on the synthesis of new materials and the development of clever, new immobilization strategies. 

The rapid adoption of DCC by the chemical community bodes well for continued development and enhancement over the coming years. It stands to reason that the importance of stereochemical selectivity in a broad array of research problems (catalysis, sensors, etc.) will drive the evolution of the topic of this chapter to higher and higher levels of sophistication. 

This rather obvious observation led us to begin work on chemical sensors that look for the actual explosive molecules. Undoubtedly, other researchers came to similar conclusions because several programs were begun at about the same time to develop this basic idea. Chapter 4 provides a brief glimpse at the history of some of these programs. 

Figure 1,17 — Focal points for research and development in (bio)chemical sensors. For details, see text.

Dittmann, B., Nitz, S. (2000) A new chemical sensor on a mass spectrometric basis-development and applications. In Schieberle, R, Engel, K.H. (eds) Erontiers of flavour Science, Proceedings of the 9th Weurman Flavom Research Symposium, Ereising, Germany, 22-25 June 1999, pp 153-159. 

Organometallic compounds play an essential role in the development and production of new materials for industry, especially electronic materials. The role of metalloporphyrins as chemically interactive materials in chemical sensors has interested researchers for a long time (1-4). The rich coordination chemistry of porphyrins is responsible for their use in chemical-sensor... 

MAJOR limitation TO research on surface-exchange and flux measurements is the lack of sensitive, reliable, and fast-response chemical species sensors that can be used for eddy correlation flux measurement. Therefore we recommend that continued effort and resources be expended in developing chemical species sensors with the responsiveness and sensitivity required for direct eddy correlation flux measurements. This recommendation (I) was assigned the first priority in the report of the recent Global Tropospheric Chemistry workshop jointly convened by the National Science Foundation, the National Aeronautics and Space Administration, and the National Oceanic and Atmospheric Administration. The authors of the report recognized that the limited availability of fast, accurate chemical sensors is a major measurement challenge in the field of atmospheric chemistry. 

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