Sensor materials for the future: Intelligent materials

Recently, there has been a renewed interest in the development of sensor materials. Four major trends can be discerned in this new research, i.e., (1) single crystal to poly crystal to amorphous material; (2) static material to dynamic material; (3) simple material to composite material; (4) atomic (molecular) synthesis of sensor material. These trends are an approach to obtaining ‘intelligent materials’.Up to now, sensor devices have been made using materials with given characteristics. In future, however, sensor materials should be designed to give the desired characteristics of sensor devices. These trends towards intelligent materials will be discussed here.     

Nanostructured materials

In the cores of lattice defects (e.g. dislocations, grain boundaries, phase boundaries etc.) a special state of solid matter exists due to the forces (constraints) between the atoms (molecules) in the core region of the defects and the atoms (molecules) in the surrounding strained crystal lattices. These constraints result in the formation of a solid state structure characterized by a low density (typically 60 - 80 % of the crystal density) and a very broad distribution of nearest neighbour spacings. It is the basic idea of Nanostructured Materials to utilize the atomic structures formed in the cores of defects to generate a new class of materials. This goal is achieved by incorporating so many defects into a (formerly perfect) crystal that about 50 vol % of the material consists of defect cores. The results of studies by means of electron microscopy, neutron and x-ray diffraction, various types of spectroscopy and property measurements agree with these ideas. Nanostructured Materials exhibit properties that deviate (sometimes by many orders of magnitude) from the properties of crystals and glasses with the same chemical composition.     

Supplementary materials

Table A1 A matrix of 1369 structural variables of 20 coded amino acids and loading equations of 13 principle components(PCs)No. The variable name t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 t11 t12 t13 1 Mdeosclericputloarrs w eight constitutional 0.0389 ?0.0008 0.016…     

Energy materials

Fundamental advances in the solid state chemistry of ionically conducting solids are essential if we are to address the problem of clean energy supply and hence global warming. Several new directions are discussed in this context. Recently, we have synthesised, for the first time, TiO₂ nanowires. They possess diameters between 20 and 40 nm and may be up to several microns in length. The crystal structure is that of the less well known polymorph TiO₂B. The nanowires are excellent intercalation hosts for Li, reaching a composition of Li_0.91TiO₂B (corresponding to 305 mAh g⁻¹ of charge stored), almost twice the capacity of anatase. After a small irreversible capacity loss on the first cycle, reversibility of intercalation is excellent. This material is of interest as a potential negative electrode in rechargeable lithium batteries. The first synthesis of ordered mesoporous Fe₂O₃ materials is described. Two forms, exhibiting respectively pores ordered in 2 and 3 dimensions have been characterised. Metal–polyether complexes (polymer electrolytes), the solid state analogues of the crown ether complexes, are discussed. For some 30 years it was believed that only amorphous lithium-polyether complexes supported ionic conductivity, recently we have shown that this is incorrect. We have reported the first example of crystalline polymer electrolytes supporting ionic conductivity. New developments involving the doping of stoichiometric metal–polyether complexes, specifically PEO₆:LiXF₆, where X=P,As,Sb, are discussed that enhance the conductivity by up to 2 orders of magnitude.     

Polymer materials of medical purpose and materials for dentistry

A wide range of polymer materials for medical purposes based on polysiloxane developed at the State Research Institute of Building Structures is presented. The properties of compositions cured by both end hydroxyl groups and the reaction of hydroxylation are considered and examples of their applications are presented.     

Old materials with new tricks: multifunctional open-framework materials

The literature on open-framework materials has shown numerous examples of porous solids with additional structural, chemical, or physical properties. These materials show promise for applications ranging from sensing, catalysis and separation to multifunctional materials. This critical review provides an up-to-date survey to this new generation of multifunctional open-framework solids. For this, a detailed revision of the different examples so far reported will be presented, classified into five different sections: magnetic, chiral, conducting, optical, and labile open-frameworks for sensing applications. (413 references.)     

Enhancing the flame-retardant performance of wood-based materials using carbon-based materials

We sought to improve the flame-retardant performance of wood-based materials through the development of a coating material using carbon-based materials. The coating materials were applied to the surfaces of wood-based materials used for interior materials and furniture. We measured fire characteristics of the coated wood-based materials using a cone calorimeter. The coating materials were prepared by the mixing of carbon materials, such as natural graphite, expandable graphite, and exfoliated graphite nanoplatelets, in water-based coating materials. TG analysis revealed that water-based coating materials/carbon material-blended composites had good thermal durability in the working temperature ranges. The flame-retardant performance was confirmed through cone calorimeter experiments, and the result of the experiment satisfied the standard for flame-retardant performance in ISO 5600-1.     

Reference materials and certified reference materials for spectrometry in Romania

Several reference materials (RMs) and certified reference materials (CRMs) are widely used in Romania as measurement standards in different spectrochemical measurements. Among them, single element standard solution certified for their mass concentration play a key role in ensuring the required traceability of results expressed in this measurement unit. A short review of the locally available elemental RMs and CRMs used in atomic spectrometry or in other analytical techniques where aqueous standard solutions are required (usually called RMs or CRMs for spectrometry) is given. The experience of the INM in preparation and certification of such materials is described. Some aspects regarding their use for ensuring the accuracy and for confirmation of the traceability of analytical measurements, especially through calibration and metrological validation of main instrument performances, are discussed.     

Cement-polymer adhesive materials

Tile adhesives consisting of Portland cement, fillers, water, and polymer admixtures are described. The key components of tile adhesives are considered. Special attention is paid to polymer components of these adhesives. Information on the largest manufacturers of tile adhesives in Russia is given.     

New fluoropolymer materials

We report the synthesis of two classes of fluoropolymers that could impact several key lithographic techniques; one has potential applications in next generation photolithography (193 nm, 157 nm, and immersion lithography) and the other in lithographic techniques which are emerging as viable alternatives to photolithography for future applications (i.e., soft lithography).     

Biological soft materials

With one or two exceptions, biological materials are "soft", meaning that they combine viscous and elastic elements. This mechanical behavior results from self-assembled supramolecular structures that are stabilized by noncovalent interactions. It is an ongoing and profound challenge to understand the self-organization of biological materials. In many cases, concepts can be imported from soft-matter physics and chemistry, which have traditionally focused on materials such as colloids, polymers, surfactants, and liquid crystals. Using these ideas, it is possible to gain a new perspective on phenomena as diverse as DNA condensation, protein and peptide fibrillization, lipid partitioning in rafts, vesicle fusion and budding, and others, as discussed in this selective review of recent highlights from the literature.     

Nanoscale metal-organic materials

Metal-organic materials are found to be a fascinating novel class of functional nanomaterials. The limitless combinations between inorganic and organic building blocks enable researchers to synthesize 0- and 1-D metal-organic discrete nanostructures with varied compositions, morphologies and sizes, fabricate 2-D metal-organic thin films and membranes, and even structure them on surfaces at the nanometre length scale. In this tutorial review, the synthetic methodologies for preparing these miniaturized materials as well as their potential properties and future applications are discussed. This review wants to offer a panoramic view of this embryonic class of nanoscale materials that will be of interest to a cross-section of researchers working in chemistry, physics, medicine, nanotechnology, materials chemistry, etc., in the next years.     

Thermo-responsive monolithic materials

One of the recent major improvements of HPLC was the introduction of monolithic silica columns, which have the advantage of faster separation and lower back pressure as compared to common silica beads. Here, we present an interesting alternative to such reversed-phase monolithic columns by a convenient coupling route of a thermo-responsive polymer to hydrophilic silica monoliths. Poly(N-isopropylacrylamide) (PNIPAM) was polymerized in solution via a reversible addition fragmentation chain transfer (RAFT) polymerization technique and coupled then in situ onto an amino-modified silica monolithic column. These columns were compared with RP-18 monolithic columns in the separation of steroids under isocratic condition in aqueous mobile phase. Separation is optimized just by changing the temperature, instead of changing the mobile phase composition.     

Organosilicon rapid-curing materials

The article describes organosilicon rapid-curing compositions developed and produced by the State Research Institute of Chemistry and Technology of Organoelement Compounds Institute on pilot scale. Polymers based on these compositions are characterized by superior dielectric properties, water and moisture resistance, and sufficient adhesion to numerous engineering materials; furthermore, they are capable of operating in aggressive environments, in a vacuum, and under the action of shock and thermal loads in the temperature range from −60 (−90) to +200 (+350)°C, and possess chemical and biological inertness. The fields of application of rapid-curing compositions are described. The prospects of developing new materials are considered.     

Contemporary superconducting materials

Superconductors currently under active study are briefly described from a chemical perspective. The author's current views on those superconductors, the role of theory in searching for new superconductors, and possibilities for new superconducting materials that might be found in the future are presented.     

Reference materials and certified reference materials for spectrometry in Romania

Several reference materials (RMs) and certified reference materials (CRMs) are widely used in Romania as measurement standards in different spectrochemical measurements. Among them, single element standard solution certified for their mass concentration play a key role in ensuring the required traceability of results expressed in this measurement unit. A short review of the locally available elemental RMs and CRMs used in atomic spectrometry or in other analytical techniques where aqueous standard solutions are required (usually called RMs or CRMs for spectrometry) is given. The experience of the INM in preparation and certification of such materials is described. Some aspects regarding their use for ensuring the accuracy and for confirmation of the traceability of analytical measurements, especially through calibration and metrological validation of main instrument performances, are discussed.