Search results for "Note"
showing 10 items of 10709 documents
Building molecular models using screw-on bottle caps
2013
Chemical models can be built using screw-on bottle caps. Two identical caps can be joined together by thermal welding to form atoms, and the resulting atoms can be joined together by welding or by hot polymer glue to form molecules. The method is easy, can be applied at every level of chemical education, and gives access to an unlimited number of models at almost no cost. It inspires hands-on activity of pupils and can be used to show the dependence between the three-dimensional structure of molecules and their chemical, physical, and biological features.
Synthesis and bio-functionalization of magnetic nanoparticles for medical diagnosis and treatment
2011
The synthesis of multifunctional magnetic nanoparticles (NPs) is a highly active area of current research located at the interface between materials science, biotechnology and medicine. By virtue of their unique physical properties magnetic nanoparticles are emerging as a new class of diagnostic probes for multimodal tracking and as contrast agents for MRI. Furthermore, they show great potential as carriers for targeted drug and gene delivery, since reactive agents, such as drug molecules or large biomolecules (including genes and antibodies), can easily be attached to their surface. On the other hand, the fate of the nanoparticles inside the body is mainly determined by the interactions wi…
Preparation and processing of nanocomposites of all-inorganic lead halide perovskite nanocrystals
2021
Abstract Solution processed all-inorganic trihalide perovskite nanocrystals are potential materials for the fabrication of future generation optoelectronic devices. However, the surface of the perovskite nanocrystals should be encapsulated to prevent degradation. Because of their stability under ambient conditions, nanocomposites of perovskite nanocrystals have been intensively researched for display applications. Perovskite nanocrystals dispersion or growth in a polymer matrix imparts structural stability and influences the optical properties, preventing effects such as halide migration. Developing flexible, high-performance lighting devices through perovskite nanocomposites will need to b…
Effect of the Biopolymer Charge and the Nanoclay Morphology on Nanocomposite Materials
2016
This work represents a contribution to the design, preparation, and characterization of nanocomposite materials based on biocompatible components. The effects of composition, filler geometry, and polymer charge were highlighted, and their role on the final properties of the nanocomposites was revealed. We combined some biopolymers (methylcellulose, alginate, chitosan) with two nanoclays (kaolinite sheets and halloysite nanotubes) to prepare nanocomposites by means of the casting method from water. The thermal stability, the surface wettability, and the mechanical properties of the obtained films were studied. SEM micrographs highlighted the surface morphology of the biocomposite materials. …
Light-Fueled, Spatiotemporal Modulation of Mechanical Properties and Rapid Self-Healing of Graphene-Doped Supramolecular Elastomers
2017
Gaining spatially resolved control over the mechanical properties of materials in a remote, programmable, and fast-responding way is a great challenge toward the design of adaptive structural and functional materials. Reversible, temperature-sensitive systems, such as polymers equipped with supramolecular units, are a good model system to gain detailed information and target large-scale property changes by exploiting reversible crosslinking scenarios. Here, it is demonstrated that coassembled elastomers based on polyglycidols functionalized with complementary cyanuric acid and diaminotriazine hydrogen bonding couples can be remotely modulated in their mechanical properties by spatially conf…
Numerical model for composite material with polymer matrix reinforced by carbon nanotubes
2008
Due to the high stiffness and strength, as well as their ability to act as conductors, carbon nanotubes are under intense investigation as fillers in polymeric materials. The nature of the carbon nanotube/polymer bonding and the curvature of the carbon nanotubes within the polymer have arisen as particular factors in the efficacy of the carbon nanotubes to actually provide any enhanced stiffness or strength to the nanocomposite. Here the effects of carbon nanotube curvature and interface interaction with the matrix on the nanocomposite stiffness are investigated using nanomechanical analysis. In particular, the effects of poor bonding and thus poor shear lag load transfer to the carbon nano…
A numerical-analytical model for the characterization of composites reinforced by carbon nanotubes
2010
A mixed model, numerical-analytical, is presented that allows one to predict the elastic properties of carbon nanotube (CNT)/polymer composites containing a random distribution of CNTs, while taking account of the curvature that they show when immersed in the polymer. This hybrid approach is a significant advance over micromechanical modeling and can be applied to all nanostructured composites.
Thermomechanical degradation of PLA-based nanobiocomposite
2015
Nanobiocomposites are a new class of biodegradable polymer materials with nanometric dispersion of inert particles in a biodegradable polymer matrix that show very interesting properties often very different from those of conventional- filled polymers and also biodegradability. An important issue in the applications of the biodegradable polymers is their easy degradability during processing due to the thermomechanical stress or to the presence of humidity. In this work, the thermomechanical degradation behavior of a nanobiocomposite made by a PLA-based blend and an organomodified montmorillonite has been investigated. The degradation kinetics has been followed by means of rheological, mecha…
Nanocomposites for Novel Sensing Systems
2012
The work performed under the National Research Program of Latvia and presented here is about advanced, chemical stimuli responsive materials. Sensor materials are produced on the basis of metallophthalocyanines or zirconia nanocrystals with the purpose of detecting small size molecular compounds like NH3, O2 and O3. Polymer/nanostructured carbon composite is produced to detect large size molecular compounds like organic vapour. Basic gaseous compound sensing principles are discussed within this paper.
Morphology control in biphasic hybrid systems of semiconducting materials.
2015
Simple blends of inorganic nanocrystals and organic (semiconducting) polymers usually lead to macroscopic segregation. Thus, such blends typically exhibit inferior properties than expected. To overcome the problem of segregation, polymer coated nanocrystals (nanocomposites) have been developed. Such nanocomposites are highly miscible within the polymer matrix. In this Review, a summary of synthetic approaches to achieve stable nanocomposites in a semiconducting polymer matrix is presented. Furthermore, a theoretical background as well as an overview concerning morphology control of inorganic NCs in polymer matrices are provided. In addition, the morphologic behavior of highly anisotropic na…