Abstrait

An optimized methodology to analyze biopolymer capsules by environmental scanning electron microscopy

Egle Conforto, Nicolas Joguet, Jean-Eudes Vendeville, Carine Chaigneau, Thierry Maugard

 We present an optimal approach for studying the surface properties and interior structure of biopolymer capsules using Scanning Electron Microscopy (SEM) in environmental mode. During studies, a water vapour pressure of 1.3–2.0 mbar is supplied into the SEM specimen chamber to increase the capsule surface's electrical and thermal conductivity and protect it from harm. The fundamental benefit of this procedure is that it requires no preparation and, more importantly, no metallic coating is formed on the specimen's surface, keeping its natural form. It prevents the introduction of preparation artefacts that might alter the capsule's surface and shape, as well as masking information on critical features like as porosities, roughness, coating continuity, and fissures. In addition, chemical contrast is retained in Backscattered Electron (BSE) pictures of unprepared samples, allowing for visualisation of the capsule's internal structure, envelope quality, and so on. Secondary electrons (SE) pictures illustrate the surface shape of uncovered capsules made of an inorganic salt. The coating permeability and coating-core interactions may be evaluated using BSE images of the same salt coated with 10% type A gelatin. This information was also acquired from a study in which hydrogenated vegetable oil was used to wrap capsules containing the same salt. Fine features of gelatin and, in particular, fatty coatings may be seen, which are difficult to study using typical SEM methods. Environmental Energy Dispersive Spectroscopy (EDS) studies have been successfully done to obtain the relative concentration C/O for several simple fatty compounds, such as stearic acids. Finally, this technique allows for a reliable assessment of the parameters employed in capsule development for research and industrial applications, as well as capsule functionality, which is critical for technological advancement in this field. Although there is no formal definition, nanomaterials are materials with at least one dimension of less than 100 nanometers. Nanofilms and coatings (100 nanometers in one dimension), nanotubes and wires (100 nanometers in two dimensions), and nanoparticles (100 nanometers in three dimensions) are among them. Nanoparticles can be found in nature, created inadvertently, or purposefully made. The focus of this review will be on nanoparticles that have been created or created (ENPs). Nanoparticles have distinct physico-chemical characteristics than the bulk substance they come from because of their size. Changes in optical characteristics can affect colour, thermal behaviour, material strength, solubility, conductivity, and (photo) catalytic activity, among other things. Nanoparticles function as a connection between atomic or molecular structures and bulk materials. Nanoparticles formed of semiconducting materials with a size of between 1 and 10 nm, for example, are tiny enough to display quantum effects and are commonly referred to as quantum dots. The shift in surface-to-volume ratio, on the other hand, is probably the most important effect on nanoparticle behaviour. Because the number of atoms at the particle surface grows as the particle size decreases, the surface qualities can override the bulk material's qualities