ISO 20579-4:2018 pdf free

ISO 20579-4:2018 pdf free.Surface chemical analysis一Guidelines to sample handling, preparation and mounting
The literature contains many examples of ‘identical’ nanoparticles for which very different behaviours have been demonstrated. Such differences can be caused by minor variations in the synthesis method or processing of the materials[15][36]. Careful research has reported difficulties with reproducing well-defined nanoparticles using the same detailed and careful processes[15][22]. Francia et al.[22] described challenges in the preparation of core-shell nanoparticles. Samples prepared by the same experienced chemist, using the same identical equipment and the same lots of reagents, showed significant batch-to-batch variation in both the percentage composition and surface chemistry of the nanoparticles. Without analytical measurements of the surface chemistry on these particles, the differences would have gone unrecognized and the causes of the inconsistency of results would have been unknown.
Discussions with commercial vendors suggest they can face similar issues because a synthesis process used for years seems to ‘drift’ with time and particle properties produced by the same well-documented process might produce particles with differing properties. Careful technical records of procedure (and the person executing it), storage times and conditions, and processing, as well as measurements that can assist identification of particle variations, are needed, together with the development of ‘failure’ margins for quality assurance of ‘batch-to-batch’ reproducibility.
Because surface or interfacial atoms make up a large fraction of the total atoms in nanomaterials,surfaces and interfaces can have a major impact on the properties of nano-objects. Particle surfaces usually include deliberate or environmentally induced coatings. Both inconsistency of deliberate coatings, such as reported by Francia et al.[22], or the presence of unplanned elements or coatings (such as fluorine on a copper oxide particle[4]) can cause unexpected problems. Often the presence of an unexpected coating or surface element is not readily detected without the use of specific surface-sensitive analysis tools. The type of information that can be obtained by surface analysis tools has been highlightel11[9][37-41].ISO 20579-4 pdf free download.