Zeolite molecular sieves are indispensable materials for acid-based catalysis and separation processes. This article overviews zeolite-type microporous materials containing a secondary system of larger (meso-/macro-) pores. These materials, often referred to as hierarchical zeolites, show better performance in reactions where slow mass transport impedes the reaction rate. A critical analysis of different synthetic strategies for preparation of hierarchical zeolites is presented. The industrial prospects of these materials are also discussed.

This article reviews post-analysis processing methods for data acquired using atom probe tomography (APT). Field-induced aberrations of APT images arise from distorted ion flight trajectories and differences in ion evaporation rates. Addressing this issue requires the development of image processing tools that yield three-dimensionally reconstructed images that reliably reflect the original specimens. One of the biggest advantages of the APT technique is its ability to collect information about millions of individual atoms. Understanding these data requires the development of mathematical and statistical data mining tools, involving disciplines beyond the basic physics of APT. The above issues have important implications for addressing materials science-related questions.

The integration of synchrotron and high-pressure techniques has significantly advanced research in materials science, giving rise to many important discoveries in physics, chemistry, environmental science, and many other fields of physical and engineering sciences. The relevant frontier work in multiple disciplines is reviewed. The selected studies include high-pressure superconductivity, lattice dynamics of materials, plastic deformation of nanomaterials, polyamorphic transitions and devitrification in metallic glass, rheology of minerals, and high-pressure chemistry probing.

Materials that can expand and collapse, fold, and transform into a variety of shapes have attracted significant interest and have applications in the design of flexible electronics, color displays, smart windows, actuators, sensors, and both photonic and phononic devices. But how can we render a rigid device super-flexible so that it can wrap around a sphere without bending and stretching? How can flat surfaces be transformed into any desired three-dimensional (3D) structure without disruptive or catastrophic deformation? The key lies in cuts. Here, we review recent research progress in the design of super-conformable and foldable materials by employing fractal cutting and lattice-based kirigami elements that combine cutting and folding. By prescribing cuts with different motifs, identifying edges in the right geometry, and by programming the folding directions, we show that a single flat sheet can be transformed into a variety of targeted 2D and 3D structures—a pluripotent platform for new technologies.

The rapid growth of scientific publications necessitates new methods to understand the direction of scientific research within fields of study, ascertain the importance of particular groups, authors, or institutions, compute metrics that can determine the importance (centrality) of particular seminal papers, and provide insight into the social (collaboration) networks that are present. We present one such method based on analysis of citation networks, using the freely available CiteSpace Program. We use citation network analysis on three examples, including a single material that has been widely explored in the last decade (BiFeO3), two small subfields with a minimal number of authors (flexoelectricity and Kitaev physics), and a much wider field with thousands of publications pertaining to a single technique (scanning tunneling microscopy). Interpretation of the analysis and key insights into the fields, such as whether the fields are experiencing resurgence or stagnation, are discussed, and author or collaboration networks that are prominent are determined. Such methods represent a paradigm shift in our way of dealing with the large volume of scientific publications and could change the way literature searches and reviews are conducted, as well as how the impact of specific work is assessed.

Conducting polymers are difficult to process, since unlike conventional polymers, they generally do not dissolve in common solvents or melt. By synthesizing nanostructured forms of the conjugated polymer polyaniline, simple methods for making conducting polymer inks become possible. By using either interfacial polymerization or a rapid-mixing technique, nanostructured polyaniline has been synthesized in a readily scalable process. Polyaniline nanofibers make excellent sensors for acids and bases. When decorated with metal nanoparticles, they can be used for molecular memory devices and catalysis. Using a flash from a camera, polyaniline nanofibers can be melted and patterned to make sensors, actuators, and asymmetric membranes. Single crystals of tetraaniline can be grown that exhibit conductivities approaching that of the bulk polymer.

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.

The twinning-induced plasticity effect enables designing austenitic Fe-Mn-C-based steels with >70% elongation with an ultimate tensile strength >1 GPa. These steels are characterized by high strain hardening due to the formation of twins and complex dislocation substructures that dynamically reduce the dislocation mean free path. Both mechanisms are governed by the stacking-fault energy (SFE) that depends on composition. This connection between composition and substructure renders these steels ideal model materials for theory-based alloy design: Ab initio-guided composition adjustment is used to tune the SFE, and thus, the strain-hardening behavior for promoting the onset of twinning at intermediate deformation levels where the strain-hardening capacity provided by the dislocation substructure is exhausted. We present thermodynamic simulations and their use in constitutive models, as well as electron microscopy and combinatorial methods that enable validation of the strain-hardening mechanisms.

This article provides a brief introduction to third-order nonlinear optical materials, including both the real and imaginary components, and is intended to be a personal perspective of the field. It describes applications that can be enabled by molecules with large two-photon absorption (2PA) cross sections and how symmetrical donor–(π-bridge)–donor molecules exhibit large cross sections associated with significant changes in quadrupole moment between the ground- and first-excited electronic states. The application of such materials for 2PA three-dimensional microfabrication is described. The article then turns its focus to materials for all-optical switching applications and explains how cyanine-like molecules can be developed to have both very large real third-order nonlinear coefficients and small 2PA cross sections, both of which are necessary for efficient all-optical switching materials.

Future electronics will be conformal, bendable, and wearable. Taking inspiration from the characteristics of human skin, we are developing a new generation of electronic materials to enable devices that are flexible, stretchable, biodegradable, and self-healable. We have developed various sensors and circuits, all of which are based on organic materials, polymers, and carbon nanomaterials. These materials will provide us with a long-term path toward adding various skin-inspired functions.

Research aimed at designing and optimizing open framework materials for commercial applications tend to focus on two critical objectives: identifying synthesis conditions that yield crystals with tailored physicochemical properties, and unlocking the untapped design space to achieve theoretical structures that far outnumber the list of synthetically realized materials. Accomplishing these goals requires detailed knowledge of nucleation in order to cultivate efficient, facile, and economical methods of controlling crystallization. The vast number of open framework materials that can be engineered through the judicious selection of inorganic or organic building units hold the promise for future discovery of materials with unique and superior properties compared to available porous materials. Herein, we review what is known about the nucleation of open framework crystals, highlighting the voids in our understanding of nucleation pathways, and we offer guidelines for advancing crystal engineering in this exciting area of research.

Thermogelling polymers belong to a class of stimuli-responsive hydrogels that undergo a macroscopic sol-to-gel transition in response to temperature. Much of the ongoing research in this field is focused on hydrogels for biomedical applications as an injectable sustained drug-release matrix or scaffolds for tissue regeneration. Despite robust developments in biodegradable thermogelling polymers in recent decades, the field still faces challenges in the optimization of materials properties. Thorough investigation must be performed to understand the effectiveness of drug delivery using hydrogel-forming polymer carriers. A highlighted case study on OncoGel, an experimental drug delivery depot formulation, sheds some light on the shortcomings of biodegradable thermogelling polymers as drug delivery systems. In this article, we highlight developments in biodegradable thermoresponsive polymers for biomedical applications over the past three years, with a focus on materials/technical challenges and the approaches used to resolve these problems.

Nanoparticles are ubiquitous in both natural and synthetic environments, providing much of the chemical reactivity for geochemical, planetary, environmental, and technological processes. However, this reactivity and differences between the bulk and nanoscale are thermodynamically, as well as kinetically, controlled. Energetic effects arising from differences in surface energies of different nanomaterials lead to changes in which phases are thermodynamically stable under given conditions. This results in crossovers in polymorphic stability as a function of particle size and substantial shifts in the positions of dehydration and redox equilibria. Examples of these phenomena in aluminum, cobalt, iron, and manganese oxides are presented, and implications for catalysts, battery materials, and other functional oxides are discussed. A hypothesis is presented that low surface energy and the resulting relatively weak water binding on the surface leads to better function when electrons or ions are transferred at the solid-solution interface.

Research universities can be more than centers of research and education; in the best cases, they can also be hotbeds of innovation and entrepreneurship. We have examined successful innovators and noted similarities and differences. This article describes results from a preliminary investigation that supports a vibrant innovation ecosystem in the fields of materials, energy, and environment at Stanford University. The results are drawn from interviews of a small number of successful innovators in these fields. All of the interview subjects were similar in that they operated within a gap between the present state of the art and a vision of how a particular innovation could reshape the world around them. Important differences were also observed. We found that successful models can be grouped into three successful classes of inquiry: basic research, the search for new solutions to well-known problems, and exploiting the evolutionary arc of technology. Each class of inquiry appears to be matched to definite approaches, and we believe that distinct factors can be used to drive cultural change and enhance the effectiveness of researchers and organizations. Future research in this area may carefully examine these factors and the broader applicability of these findings to other innovation contexts.

The US Materials Genome Initiative (MGI) has emphasized the need to accelerate the discovery and development of materials to maintain industry competitiveness in new and existing markets. While largely interpreted as an initiative arising from the materials community, it is important to address the coupling of materials with manufacturing and all other relevant aspects of product development in order to maximize its impact. The dual thrusts of Integrated Computational Materials Engineering and the MGI represent a long-term vision of industry, academic, and government stakeholders. The goal is to build a new kind of coupled experimental, computational, and data sciences infrastructure. The emphasis is on high-throughput methods to accelerate historical sequential processes of serendipitous materials discovery and largely empirical materials development by leveraging computation and modern data sciences and analytics. The notion of a materials innovation ecosystem is introduced as the framework in which to pursue acceleration of discovery and development of materials consisting of various elements of data sciences, design optimization, manufacturing scale-up and automation, multiscale modeling, and uncertainty quantification with verification and validation.

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.