Micrograph of the Month(s) from the Journal of Sol-Gel Science and Technology

Each month, the ISGS Newsletter features an interesting and striking micrograph (or series of micrographs) chosen from a recent issue of the Journal of Sol-Gel Science and Technology or from unpublished sources such as PhD theses, etc (with full attribution given). If you know of any interesting images that might be suitable, please contact the ISGS Newsletter Editor for inclusion. The micrographs can be optical, SEM, TEM, AFM, etc, and a brief description of the samples should be provided.

This months’ images are taken from four different papers in the latest issues of JSST and once again highlight the breadth of sol-gel science and technology, together with the areas in which our community is making an impact.

The first series is taken from the work of Borovik, Oestreicher, Angelomé, Barja and Jobbágy entitled “Room temperature synthesis of lanthanum phosphates with controlled nanotexture as host for Ln(III) through the Epoxide Route” (JSST, (2022); https://doi.org/10.1007/s10971-022-05744-w), and explores the use of an epoxide route for synthesising Eu(III)-doped LaPO4 as a Rhabdophane phase at ambient temperature. The work demonstrates control of the size and shape of the LaPO4 particles by modulating the mixed solvent system used for their synthesis, with diverse particle shapes such as dumbbells, urchins and needles being obtained with sizes from < 200 nm to > 5 µm.

The second series of micrographs is from the work of Hamed, Ahmad, Hairom, Faridah, Mamat, Mohamed, Suriani, Soon, Fazli, Mokhtar and Shimomura. This paper, entitled “Photocatalytic degradation of methylene blue by flowerlike rutile-phase TiO2 film grown via hydrothermal method” (JSST, (2022); https://doi.org/10.1007/s10971021-05691-y), explores the effect of processing conditions such as initial alkoxide concentration on the morphology of flower-like rutile structures obtained under hydrothermal conditions. An intriguing series of film morphologies were observed, varying from rods oriented vertically on the substrate to flower-like and cauliflower-like materials. The flower-like morphology obtained using an initial alkoxide concentration of 0.10 M exhibited the best performance for the photocatalytic degradation of methylene blue.

The third series of images is from the work of Sfez, De-Botton, Avnir and Wakshlak entitled “Sol–gel glazes – a safe glass and ceramics coloring approach” (JSST, (2022); https://doi.org/10.1007/s10971-021-05699-4). This paper explores the use of organic colorants (approved for use with humans) entrapped within aluminosilicate hybrid matrices as replacements for the more toxic inorganic compounds typically used as pigments in glass and ceramic technology. Such an approach, which provides an artist’s palette consisting of thousands of colorants, reduces the energy required to produce glazed products and facilitates ready recyclability. The images on the left illustrate tiles glazed using this approach, under normal (left) and UV irradiation (second from left), while the images in the right-hand pane illustrate the artistic potential of such technology.

The final series of images is from the work of Colusso, Cicerchia, Rigon, Gomes and Martucci. This paper, entitled “Photoluminescence properties of silk–carbon quantum dots composites” ((JSST, (2022); https:// doi.org/10.1007/s10971-022-05742-y), explores solution casting approaches for producing silk fibroin-carbon quantum dot composites deposited on polydimethylsiloxane substrates. The top row of images illustrates the effect of varying the quantum dot content on the transparency of the hybrid films, while the bottom row shows the luminescence of the samples under UV irradiation. The best combination of transparency and luminescence intensity is achieved for a quantum-dot loading of 0.5 wt%, with higher concentrations leading to aggregation of the quantum dots and associated scattering and quenching of the luminescence.