Structural hierarchy coupled with material heterogeneity is often identified in natural materials, from the nano- to the macroscale. It combines disparate mechanical properties, such as strength and toughness, and multifunctionality, such as smart adhesion, water repellence, self-cleaning, and self-healing. Hierarchical architectures can be employed in synthetic bioinspired structured materials, also adopting constituents with superior mechanical properties, such as carbon nanotubes or graphene. Advanced computational modeling is essential to understand the complex mechanisms that couple material, structural, and topological hierarchy, merging phenomena of different nature, size, and time scales. Numerical modeling also allows extensive parametric studies for the optimization of material properties and arrangement, avoiding time-consuming and complex experimental trials, and providing guidance in the fabrication of novel advanced materials. Here, we review some of the most promising approaches, with a focus on the methods developed by our group.

Timber, steel, and concrete form the triumvirate of structural materials used in construction. Each material possesses particular attributes, with cost and ease of use often providing the determining factor in selection when structural requirements are equal. This article aims to provide insight into the unique capabilities that steel can offer in construction. Beginning with the advent of the Industrial Revolution, developments in alloy chemistry, impurity control, and thermomechanical processing to produce different geometries have continued to make steel an attractive choice in residential and commercial construction. Changing demographics and the needs of future cities are discussed in terms of steel construction members, construction strategies, and functional coatings.

Tin oxide (SnO2) hollow spheres modified with titanium dioxide (TiO2) nanowires (NWs) synthesized by sequential hydrothermal reactions were investigated as photoanodes for dye-sensitized solar cells. Not only does the hydrothermal treatment form numerous short TiO2 NWs on the surface of SnO2 spheres, but also passivates the surface of SnO2. Consequently, the specific surface area of the photoanode and dye loading are almost doubled, at the same time the surface defects and charge recombination are both appreciably reduced. As a result, the short-circuit photocurrent density and open-circuit photovoltage both greatly increased. The power conversion efficiency of the solar cells increases from 0.4% to 2.9%.

Machining is an important technological process in many areas of industry. The efficiency of machining determines the quality of many industrial products. Machining efficiency and cost depend on the properties, strength, and microstructure of the machining materials. One of the promising ways to increase the reliability and wear resistance of machining tools is the development and use of hierarchical machining materials. In the area of machining materials, designed typically as binder/reinforcement composites, hierarchical structures are realized as lower-scale secondary reinforcements (such as nanoparticles in the binder, or polycrystalline, aggregate-like reinforcements, also at several scale levels). Such materials can ensure better productivity, efficiency, and lower costs of drilling, cutting, grinding, and other technological processes. This article reviews the main groups of hierarchical machining materials and their performance.

This work reports the growth of crystalline SrHfx Ti1−x O3 (SHTO) films on Ge (001) substrates by atomic layer deposition. Samples were prepared with different Hf content x to explore if strain, from tensile (x = 0) to compressive (x = 1), affected film crystallization temperature and how composition affected properties. Amorphous films grew at 225 °C and crystallized into epitaxial layers at annealing temperatures that varied monotonically with composition from ~530 °C (x = 0) to ~660 °C (x = 1). Transmission electron microscopy revealed abrupt interfaces. Electrical measurements revealed 0.1 A/cm2 leakage current at 1 MV/cm for x = 0.55.

In this study, “within the environment” and “within the contact” in situ tribology techniques are combined in order to study the interfacial processes in lubricated metallic (i.e., aluminum-based) sliding conditions. The evolution of the roughness follows the trend of the coefficient of friction closely, with initially low values followed by higher roughness during steady state. Similarly, the transfer film behavior correlates well with the roughness of the worn surfaces and the subsurface microstructure of the worn surfaces. The effect of normal load on the running-in behavior is also studied in terms of differences in the interfacial processes.

Establishing strategies for high-resolution micrometer to subnanometer structural control is an essential feature of any versatile materials design paradigm. Colloidal crystal (CC) templating not only establishes tunable replica pore topologies, but interfacial- and confinement-mediated phenomena extend its impact for tailoring properties such as pore hierarchy, topological diversity, and macroscopic morphology, as well as nucleation, growth, and crystallinity. Coupled with emerging strategies for “single-pot” template-replica co-assembly and efforts to expand the accessible materials palette, CC-templating offers promise for application-driven, rational materials design.