Water is the basis of life in the world. Unfortunately, resources are shrinking at an alarming rate. The lack of access to water is still the biggest problem in the modern world. The key to solving it is to find new unconventional ways to obtain water from alternative sources. Fog collectors are becoming an increasingly important way of water harvesting as there are places in the world where fog is the only source of water. Our aim is to apply electrospun fiber technology, due to its high surface area, to increase fog collection efficiency. Therefore, composites consisting of hydrophobic and hydrophilic fibers were successfully fabricated using a two-nozzle electrospinning set up. This design enables the realization of optimal meshes for harvesting water from fog. In our studies we focused on combining hydrophobic, polystyrene (PS) and hydrophilic, polyamide 6 (PA6) surface properties in the produced meshes, without any chemical modifications, based on new hierarchical composites for collecting water. This combination of hydrophobic and hydrophilic material cause water to condense on the hydrophobic microfibers and to run down on the hydrophilic nanofibers. By adjusting the fraction of PA6 nanofibers we were able to tune the mechanical properties of PS meshes and importantly increase the efficiency in collecting water. We combined a few characterization methods together with novel image processing protocols for the analysis of fiber fractions in the constructed meshes. The obtained results show a new single-step method to produce meshes with enhanced mechanical properties and water collecting abilities that can be applied in existing Fog Water Collectors. This is a new promising design for fog collectors with nano-and macro-fibers which are able to efficiently harvest water, showing a great application in comparison to commercially available standard meshes.

Among reported for the first time Cr-containing high entropy La1-xSrx(Co,Cr,Fe,Mn,Ni)O3-δ (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) perovskite-type oxides, the selected Sr-doped La0.7Sr0.3(Co,Cr,Fe,Mn,Ni)O3-δ material is documented to possess...

The calcitic prismatic units forming the outer shell of the bivalve Pinctada margaritifera have been analysed using scanning electron microscopyelectron back-scatter diffraction, transmission electron microscopy and atomic force microscopy. In the initial stages of growth, the individual prismatic units are single crystals. Their crystalline orientation is not consistent but rather changes gradually during growth. The gradients in crystallographic orientation occur mainly in a direction parallel to the long axis of the prism, i.e. perpendicular to the shell surface and do not show preferential tilting along any of the calcite lattice axes. At a certain growth stage, gradients begin to spread and diverge, implying that the prismatic units split into several crystalline domains. In this way, a branched crystal, in which the ends of the branches are independent crystalline domains, is formed. At the nanometre scale, the material is composed of slightly misoriented domains, which are separated by planes approximately perpendicular to the c-axis. Orientational gradients and splitting processes are described in biocrystals for the first time and are undoubtedly related to the high content of intracrystalline organic molecules, although the way in which these act to induce the observed crystalline patterns is a matter of future research.

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Crossed-lamellar microstructures are the most common shell-forming biomaterials in mollusks. Because of their complex hierarchical 3D arrangement and small crystallite size, previous crystallographic studies are scarce and have centered on particular species with no comprehensive analysis available. To evaluate the crystallographic diversity of the crossed-lamellar microstructures, we have studied a large set of bivalve and gastropod species with crossed-lamellar layers using X-ray diffraction and electron backscatter diffraction. From the number, distribution, and relationships of maxima, we have classified pole figures into nine different recurring crystallographic patterns. According to their crystallographic equivalences, these patterns can be grouped into five groups. A first division is established according to whether there is one or two main orientations for the c-axis of aragonite. In the latter case, each orientation corresponds to one of the two sets of alternating first-order lamellae. The two main orientations of the c-axis diverge by rotation within the plane of the first-order lamellae around either a common a- or b-axis. We also show how some patterns may derive from others. Patterns with two c-axis orientations represent crystal relationships until now completely unknown in biogenic and abiogenic aragonite and are most likely produced by particular proteomic pools

The pteropod Cuvierina constructs very lightweight, thin, flexible, and resistant shells with the most unusual microstructure: densely packed, continuous crystalline aragonite fibers that coil helically around axes perpendicular to the shell surface. The high degree of fiber intergrowth results in a particular interlocking structure. The shell is constructed by guided self‐assembly, outside the animal's soft body. A prerequisite to understand its formation is to resolve the underlying crystallographic building principle. This is basic in order to use this hierarchically structured and highly functional biomaterial as inspiration for the production of new materials. It teaches us about the optimization of structures over millions of years of evolution under strict consideration of energetic costs and efficient use of available resources and materials. We have described how helical coiling proceeds by using a combination of diffraction and imaging techniques, which complement at different levels of resolution. Despite their curling, the fibers are continuously crystalline and show a preferred crystallographic growth direction. When the latter can no more be maintained due to the imposed curving, abrupt changes across twins permit to continue growth in the desired direction. This is a nice example of how crystallographically continuous fibers can grow helically.