Surface science methodologies, such as reflection-absorption infrared spectroscopy (RAIRS) and temperature programmed desorption (TPD), are ideally suited to studying the interaction of molecules with model astrophysical surfaces. Here we describe the use of RAIRS and TPD to investigate the adsorption, interactions and thermal processing of acetonitrile and water containing model ices grown under astrophysical conditions on a graphitic dust grain analogue surface. Experiments show that acetonitrile physisorbs on the graphitic surface at all exposures. At the lowest coverages, repulsions between the molecules lead to a decreasing desorption energy with increasing coverage. Analysis of TPD data gives monolayer desorption energies ranging from 28.8–39.2 kJ mol−1 and an average multilayer desorption energy of 43.8 kJ mol−1. When acetonitrile is adsorbed in the presence of water ice, the desorption energy of monolayer acetonitrile shows evidence of desorption with a wide range of energies. An estimate of the desorption energy of acetonitrile from crystalline ice (CI) shows that it is increased to ~37 kJ mol−1 at the lowest exposures of acetonitrile. Amorphous water ice also traps acetonitrile on the graphite surface past its natural desorption temperature, leading to volcano and co-desorption. RAIRS data show that the C≡N vibration shifts, indicative of an interaction between the acetonitrile and the water ice surface.
Before joining Johnson Matthey, Tuğçe Eralp Erden was a Marie Curie PhD student at the University of Reading, UK, studying model chiral adsorption systems using synchrotron-based structural and spectroscopic techniques (1–5). After completing her PhD, she joined the advanced characterisation department at Johnson Matthey, Sonning Common, UK, where she is currently leading the surface...
The aim of this study was to prepare microcapsules and transfer them to denim and non-denim trousers using different application methods. For this purpose, shea butter as active agent was encapsulated in an ethyl cellulose shell using the spray dryer method, and capsule optimisation was studied. A morphological assessment showed that the capsules had a smooth surface and were spherical in shape. The homogenous size distribution of the capsules was supported by laser diffraction analysis. The capsules showed a narrow size distribution, and the mean particle size of optimum formulations of shea butter was 390 nm. Denim fabrics were treated with shea butter capsules using the methods of exhaustion and spraying in order to compare these application methods. The presence of capsules on the fabrics was tested after five wash cycles. The comparison of application methods found similar preferred characteristics for both the exhaustion and spraying methods. However, the spraying method was found to be more sustainable, because it allows working with low liquor ratios in less water, with lower chemical consumption and less waste than the exhaustion method, which requires working with a high liquor ratio. This study showed that the spraying method can be used as an alternative to other application methods in the market for reducing energy consumption, and shea butter capsules can provide moisturising properties to the fabrics.
This study intends to identify the characteristics of heat regulation in heat storage microencapsulated fabrics and to examine the effect of the microcapsules application method. For this purpose, phase-changing material (PCM) microcapsules were applied by impregnation and coating methods on cotton fabrics. The presence and distribution of microcapsules on the fabric surface were investigated by scanning electron microscopy (SEM). The temperature regulation of the fabrics was examined using a temperature measurement sensor and data recorder system (thermal camera). According to the differential scanning calorimetry (DSC) analysis, melting in fabrics coated with microcapsules occurred between 25.83°C–31.04°C and the amount of heat energy stored by the cotton fabric during the melting period was measured as 2.70 J g−1. Changes in fabric surface temperature due to the presence of microcapsules in the fabric structure were determined. When comparing the PCM capsules transfer methods, the contact angle of impregnated and coated fabric was obtained as 42° and 73°, respectively. Analysis of the microcapsules transferred to the fabric by impregnation and coating methods shows that the PCM transferred fabric prepared by the impregnation method performs more efficient temperature regulation. However, the analysis shows that PCM transferred fabrics prepared by coating also perform heat absorption, although not as much as the impregnation method. Performance evaluation according to the target properties of the textile will give the most accurate results for fabrics treated by coating and impregnation methods.
Iridium as a barrier coating is an important area of high-temperature application. In Part I, the introduction was presented and the different deposition processes were reviewed (1). This paper, Part II, describes the texture and structure evolution, mechanical properties, growth mechanisms and applications of Ir coatings. The mechanisms of micropore formation after high-temperature treatment are also investigated in some detail.
We herein report on the effect of gamma ray radiation on platinum, osmium, rhodium and palladium salt solutions for synthesis of nanoparticles. Pt, Os, Rh and Pd salt solutions were exposed to intense gamma ray irradiation with doses varying from 70 to 120 kGy. The metal ion salt solutions were easily converted into metal nanoparticles using this radiolysis method. The radiolytic conversion effect produced metal nanoparticles suspended in solution. For Pt, Pd and Rh a metal coating on the edges of the polypropylene tube used as a container was unexpectedly observed but not for the Os solution. X-Ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) analyses confirmed that both the coating and the metal nanoparticles correspond to the pure metal coming from the reduction of the initial salt. Quantitative analysis of the XRD patterns shows information about the size and stress of the converted metals. The production of a metal coating on polypropylene plastic tubes by gamma ray irradiation presents an interesting alternative to conventional techniques of metal deposition especially for coating the inner part of a tube.
Introduction “Atomic Layer Deposition in Energy Conversion Applications” is a series of reviews presented as nine chapters that focus on the applications of atomic layer deposition (ALD) for photovoltaics, electrochemical energy storage and photo- and electrochemical devices. These have been edited by Julien Bachmann whose research is based on the fabrication of nanostructured materials...
Fabrics with water-repellent properties are widely valued in the textile industry. It is known that fluorocarbon compounds, which are widely used for this purpose, are harmful to the environment. Therefore, within the scope of this study, a water-repellent chemical that does not contain fluorocarbon compounds was used to treat 100% cotton fabrics and compared with fluorocarbon compounds. The results show that the environmentally friendly chemical is at least as effective as the fluorocarbon compounds. According to the spray test, water repellency at ISO 5 level was obtained. In addition, the fabrics’ usage properties were assessed and high water vapour permeability, air permeability and low bending stiffness (280 mg cm) were obtained. This has yielded important results in terms of sustainability and the potential for eliminating the use of fluorocarbons for this application.