Gas sensitivity of polymeric composites with carbon nanotubes

Abstract

Abstract. The possibility of application for carbon nanotubes DEALTOM as a conductive filler for composite sensors based on polysiloxanes is shown. Sensors show predicted results on sensitivity and selectivity. Nanotubes according to chemical, physical and mechanical characteristics are suitable for modifying of specified composites and are applicable for work with rather aggressive reagents. IntroductionCombination of nano-and biotechnologies, computer, information and cognitive technologies in a single chain enables the emergence of new scientific trends on creation of inanimate matter intellectual systems, which can be used in a wide number of areas from industrial production to ecology and medicine. One of a recent trends is a chemical analysis with the use of multi-touch gas-analysis systems called «electronic nose» [1,2]. The basis of these systems is an array of sensors characterized by the sensitivity to a broad range or the whole class of analyzed substances (analytes).Nowadays a wide range of various sensors can be used in sensor arrays, but chemoresistors based on composites with the application of nanotubes are of special interest. Carbon nanotubes have a number of unique properties making their usage in chemical sensors very prospective. A large surface area of nanotubes provides efficient adsorption of molecules in many substances, and modification of carbon nanotubes surface by polymers can increase both selectivity, and sensitivity of sensors [3].Nanocomposite materials can also provide important advantages for sensors: the possibility of sensitivity control by alteration of a quantitative relationship and the nature of filler and polymer interaction, little response time owing to a fast diffusion of analyte molecules into the volume of a film and the expansion in a variety of sensitive layers [4].The purpose of this work is to examine gas sensitivity in a hybrid sensor array comprising polymeric composite sensors based on three variously modified polysiloxanes with electroconductive filler in the form of carbon black and DEALTOM nanotubes.

Hansen Solubility Parameters (HSPs): A Reliable Tool for Assessing the Selectivity of Pristine and Hybrid Polymer Nanocomposites in the Presence of Volatile Organic Compounds (VOCs) Mixtures

“…[33] Other studies opt for the Hildebrand and Scott model to compare the solubility of the coating polymer and the vapor analytes. [34,35] However, all these methods fell short in truly explaining the selectivity of polymeric materials towards VOCs and other gases. To tackle these limitations, Hansen suggested three main parameters that consider all major interactions between gas molecules and a certain polymer [36] : i) dispersion interactions caused by the Van der Waals forces; ii) dipolar interactions caused by the polarity of the molecule; and iii) hydrogen bonding interactions.…”

Materials for diagnostics of impurities of car-bon monoxide in the environment

“…Подтверждение получения нового, отличного от исходных веществ, материала проводили методом по данным рентгенофазового анализа (дифрактометр D8 Advance (Bruker)), который подтвердил получение вещества со структурой вюрцит [4].…”

“…Положение основных линий на рентгенограммах и распределение их интенсивности свидетельствуют о том, что сульфид кадмия и твердый раствор CdS:CdTe, в соотношении 23:77 масс. % имеют структуру вюрцита, а CdTe -структуру сфалерита [4].…”

“…При воздействии оксида углерода (II) на водородный показатель значения ∆рН изменяется на 0,6 единиц и смещается в слабощелочную область (в ИК-спектрах, при экспонировании в оксиде углерода увеличивается интенсивность полос, отвечающих за валентные колебания адсорбированных молекул СО (2342 см -1 )). Такое влияние газа на водородный показатель логично связать с электронной структурой и двойственной функцией молекул СО [1,4].…”