Traditional structural probes reveal little change associated with the rapid slowing down of dynamics as liquids turn into glasses. This review synthesizes results from colloid experiments, primarily real-space studies conducted over roughly the past decade, aimed at resolving the disconnect between structure and dynamics. We examine how order-agnostic measures—excess entropy, point-to-set length scales, machine-learned softness, intermediate-range order, and soft modes—provide a robust link between static structure and dynamics. A key theme that emerges from these studies is the need to consider structural correlations that extend well beyond the first nearest-neighbor shell. Finally, we discuss the devitrification of a colloidal glass and draw upon findings that demonstrate how the hidden structure in the glassy state dictates the subsequent crystallization pathway. Taken together, these studies help establish a quantitative, structure-based framework of glass formation and stability.

The development of novel materials with tailored properties is a complex, multiobjective optimization problem that has long been a challenge in materials research. The integration of artificial intelligence (AI) and machine learning (ML) techniques has shown great promise in accelerating materials discovery, design, and development by uncovering hidden correlations between processing, structure, and properties. Autonomous experimentation platforms, also known as self-driving laboratories (SDLs), have emerged as a powerful tool in this endeavor, enabling the rapid and efficient acquisition of critical data through a closed-loop feedback process. In this review, we explore the applications of AI/ML techniques to materials research and development through the lens of SDLs and examine the challenges and opportunities associated with the development and deployment of SDLs. We provide a detailed analysis of the components of an SDL, including AI-driven decision-making, experimental data generation, and knowledge representation, and discuss the current barriers to industrial adoption.

It has long been assumed that all matter will adopt simple close-packed lattices and become metallic under pressure, in accordance with the Thomas–Fermi–Dirac (TFD) model. However, this model struggles to explain pressure-driven complex structural transitions that have been observed in elements, including sodium, challenging our conventional understanding of compressed matter. Moreover, in stark contrast to the TFD model, first-principles calculations suggest that various elements and compounds become electrides under pressure. Electrides, characterized by concentrations of charge density at interstitial regions, can be thought of as ionic compounds where electrons behave as the anions. Though ambient-pressure molecular electrides have been extensively studied via experiments and computations, high-pressure electrides (HPEs) are not well-understood. The identification and characterization of HPEs have been, to date, based purely on theory, including topological analysis of the electron density and the electron localization function. Here, we review these theoretical analysis tools and suggest guidelines that can be used to classify systems as electrides. Moreover, we describe models used to rationalize the electronic structure of HPEs, drawing parallels with ambient-pressure molecular systems, and encourage the development of experimental techniques that provide evidence for the theoretically calculated charge localization.

Molecular architectures known as bottlebrush polymers provide unique opportunities to tune the structure and properties of soft materials with applications ranging from rubbers to thin films and composites. This review addresses recent developments and future opportunities in the field with an emphasis on materials science enabled by contemporary bottlebrush chemistry.

The fundamentals of our understanding of fatigue crack propagation were formed more than 60 years ago by Paul C. Paris. Since then, the run toward new metallic materials and alloys with ever finer-grained microstructures has had a large impact on research. Along with enormous variation of the microstructural length scales (i.e., grain size), the essential parameters for the description of fatigue crack growth, such as the crack propagation rate and plastic zone size, also exhibit an immense change from the subnanometer to the micrometer regime. These enormous variations in the fatigue crack growth behavior's controlling parameters motivate this contribution. This article presents an overview of the effect of grain size, from the millimeter to the nanometer grain-size regime, on fatigue crack propagation of mainly ductile metals and alloys with an attempt to summarize the most important findings and underlying physical phenomena, including with respect to selected materials such as pure iron, nickel, and austenitic and pearlitic steel.

Piezoelectric materials possess the capability to interchangeably convert electrical energy into a mechanical response. While current piezoelectric materials exhibit strong properties, known limitations have inhibited further development. This review describes the ability to combine different piezoelectric materials into a composite to create well-rounded properties. The different types of connectivity classes are described as well as important design considerations and theoretical models. The contributions from the active and passive phases are outlined, focusing primarily on ferroelectric ceramics and polymer-based composites. The key advantage of piezoelectric composites is their ability to combine the flexibility of polymers with the high electromechanical coupling and piezoelectric coefficients of ferroelectric ceramics or single crystals appropriate for a variety of applications. Composites are prominent in medical ultrasound imaging and therapy, underwater acoustic sensing, industrial structural health monitoring, energy harvesting, and numerous other emerging applications.

Hard solids with predominantly covalent–ionic bonding are finding rapidly increasing usage in many modern technologies. However, this class of solids is severely limited by their intrinsic brittleness—they break easily. It is in this context that a fundamental knowledge of brittle fracture mechanisms is of practical importance. This review covers the essential features of crack behavior in characteristically brittle solids, starting with fundamental physical and chemical models, with distinctions between equilibrium and kinetic states, stability and instability, and crack propagation and initiation. Means of imparting higher strength and toughness to otherwise brittle materials are then explored along with their pros and cons. Select technological areas where fracture properties constitute a vital facet of material function—windows and display panels, structural ceramics, biomaterials, layer structures, manufacturing, and nanomechanics—are then presented as illustrative case studies. The balance between factors such as strength and toughness, scaling and threshold effects, and crack containment and crack avoidance, as well as structure at the atomic and microstructural scales, emerge as critical factors in materials design.

In recent decades, research on persistent luminescence has led to new phosphors and promising performances. Efforts to improve the quality of phosphors’ afterglow have paved the way toward innovative solutions for many disciplines. However, there are few examples of the implementation of luminescent materials. In addition to providing a general background on persistent luminescence, the techniques used for its analysis, and its multidisciplinary potential in energy and environmental science, this article aims to explain the existing gap between the physical-chemical approach and the effective implementation of luminescent materials in larger-scale applications. It investigates engineering solutions in terms of the possible benefits of luminescence in lighting energy savings and passive cooling of urban surfaces. Finally, this article aims to reduce the abovementioned gap by suggesting what is most needed for the successful application of luminescent materials in the built environment.

High-energy diffraction microscopy (HEDM) is an implementation of three-dimensional X-ray diffraction microscopy. HEDM yields maps of internal crystal orientation fields, strain states, grain shapes and locations as well as intragranular orientation distributions, and grain boundary character. Because it is nondestructive in hard materials, notably metals and ceramics, HEDM has been used to study responses of these materials to external fields including high temperature and mechanical loading. Currently available sources and detectors lead to a spatial resolution of ∼1 μm and an orientation resolution of <0.1○. With the penetration characteristic of high energies ( E ≥ 50 keV), sample cross-section dimensions of ∼1 mm can be studied in materials containing elements across much of the Periodic Table. This review describes hardware and software associated with HEDM as well as examples of applications. These applications include studies of grain growth, recrystallization, texture development, orientation gradients, deformation twinning, annealing twinning, plastic deformation, and additive manufacturing. We also describe relationships to other X-ray-based methods as well as prospects for further development.