Evan K. Wujcik

Carbon nanotubes, graphene, and their derivatives for heavy metal removal

Carbon nanoadsorbents have attracted tremendous interest for metal ion removal from wastewater due to their extraordinary aspect ratios, surface areas, porosities, and reactivities. However, challenges still exist as they suffer from subpar dispersion and recovery, tending to aggregate, and so on. Thus, significant research efforts focus on modification of these carbon nanomaterials to increase the dispersions and recoveries, while maintaining or even enhancing the desirable properties. This review aims to give an in-depth look at recent and impactful advances in metal ion adsorption applications involving these modified carbon nanostructures. Here, the advanced design and testing of modified carbon nanostructures for metal ion removal are emphasized with comprehensive examples, and various adsorption behaviors and mechanisms are discussed, which are hoped to help the development of more effective adsorbents for water treatment.

Carbon Nanomaterials in Direct Liquid Fuel Cells

Fuel cells have attracted more attentions due to many advantages they can provide, including high energy efficiency and low environmental burden. To form a stable, low cost and efficient catalyst, we presented here the state of the art of electrocatalyst fabrication approaches, involving carbon nanotubes and their multifunctional nanocomposites incorporated with noble metals, such as Pt, Pd, Au, their binary and ternary systems. Both fuel oxidation reactions and oxygen reduction reactions were emphasized with comprehensive examples and future prospects.

Introducing advanced composites and hybrid materials

It is our great pleasure to introduce the inaugural issue of Advanced Composites and Hybrid Materials, a new interdisciplinary journal published by Springer Nature. Advanced Composites and Hybrid Materials provides a dedicated publishing platform for academic and industry researchers and offers the composites and hybrid materials field an opportunity to publish their creative research to exchange newly generated knowledge. With the rapid advancement of materials science and engineering in twenty-first century, especially the development of nanoscience and nanotechnology, the new discoveries from diverse disciplines merge into a central hub of composites and hybrid materials. Composites are defined as materials with two or more constituents with significantly different physical or chemical properties (Fig. 1a). Composites cover a wider range of dimensions of mixing components, while hybrid usually refers to the constituents at the nanometer or molecular level. The revolution of new technologies in composites has generated great impact in every single corner of our daily life [1, 2]. Based on the matrix material, composites can be categorized into polymer composites, ceramic composites, carbon composites, and metal composites. One example of the composite from each category is provided: polymer composites in Fig. 1b [3, 4], ceramic composites in Fig. 1c [5], metal composites in Fig. 1d [6], and carbon composites in Fig. 1e [7]. Nanocomposites, with one dimension of any constituent less than 100 nm, experienced a fast development over the past two decades. The large specific surface area and unique physicochemical properties of nanofillers allow flexible design of nanocomposites with unprecedented functionalities. It is expected that research in nanocomposites will keep its energetic momentum in the next few decades since there are still a lot of challenges that need to be addressed with combined research efforts [8–12]. The integration of different constituents into one unit does not simply generate a mixed property, but also creates some new physicochemical properties that were not present in the individual components. For example, negative permittivity has been discovered in engineered polymer and carbon nanocomposites [13–15], which is not existed in traditional materials.

Recent developments in bio-monitoring via advanced polymer nanocomposite-based wearable strain sensors

Recent years, an explosive growth of wearable technology has been witnessed. A highly stretchable and sensitive wearable strain sensor which can monitor motions is in great demand in various fields such as healthcare, robotic systems, prosthetics, visual realities, professional sports, entertainments, etc. An ideal strain sensor should be highly stretchable, sensitive, and robust enough for long-term use without degradation in performance. This review focuses on recent advances in polymer nanocomposite based wearable strain sensors. With the merits of highly stretchable polymeric matrix and excellent electrical conductivity of nanomaterials, polymer nanocomposite based strain sensors are successfully developed with superior performance. Unlike conventional strain gauge, new sensing mechanisms include disconnection, crack propagation, and tunneling effects leading to drastically resistance change play an important role. A rational choice of materials selection and structure design are required to achieve high sensitivity and stretchability. Lastly, prospects and challenges are discussed for future polymer nanocomposite based wearable strain sensor and their potential applications.

Dehydrogenation properties of ammonia borane-polyacrylamide nanofiber hydrogen storage composites

The current investigation seeks to measure the thermal and vibrational response of ammonia borane (NH3BH3, AB)/polyacrylamide (PAM, Mnxa0~xa0150,000) composites in bulk and electrospun fiber forms. The hydrogen release and melting temperature profiles for the composites were found to be lower than pristine AB. The kinetic analysis of the first dehydrogenation peak with respect to the heating ramp rates showed that the corresponding activation energy (Ea) revealed the greatest decrease for the electrospun fibers (~61xa0kJ/mol), as compared to the bulk composites (~95xa0kJ/mol) and the pristine AB (~133xa0kJ/mol). Overall, the nanofibers showed the greatest decrease in Ea, suggesting improved kinetic behavior. In addition to the enhanced kinetic properties, thermal gravimetric analysis showed significantly reduced weight loss for the composites. We have hypothesized that this is due to the suppression of the unwanted boracic byproducts and NH3. The weight loss decreased from 57.8% (AB) to 21.8% (fibers). Fourier-transform infrared study shows the interaction between the AB and PAM indication for the mentioned improvements. Decomposition IR studies revealed the disruption of the bonds with the broadening of the peaks and the disappearance of B–H stretch due to the dehydrogenation. These results imply that the novel composites revealed tuned properties by confining the AB molecules within the polymer matrix, having major implications in potential hydrogen storage applications.

Hexagonally patterned mixed surfactant-templated room temperature synthesis of titania–lead selenide nanocomposites

AbstractMaterials science is becoming a more and more important influencer in electronics, as new synthesis methods and new materials are consistently coming to fruition. In particular, templated synthesis schemes offer unique material options, various alignments, and micro- to nanoscale control over morphology. Surfactant and co-surfactant templating, further, offers the ability to synthesize composite materials via phase separation. Currently, nanoscale manipulation of sophisticated functional materials typically requires energy-intensive or time-intensive processes. The present study illustrates the use of a room temperature synthesis of hexagonally patterned lead selenide-titania nanocomposites, utilizing a versatile mixed surfactant-templating approach. We have found that the level of control of the simple bi-surfactant system presented illustrates the tunability of the micro- and nanostructure. The current system also utilizes a room temperature synthesis—not energy intensive—and the kinetics of the titania precursor reaction with water are extremely fast—not time intensive. Furthermore, while simple, this elegant templated synthesis strategy for creating highly organized composite materials has wide applications beyond the one currently reported, including photocatalysis, photonic crystals, sensors, among others. We anticipate our templated synthesis to be a starting point for more sophisticated nanoelectronic devices. For example, the pores can be impregnated with a variety of nanoparticles or many of the same nanoparticles can be synthesized concurrently and be well dispersed within the template. Furthermore, the templated system presented makes use of titania but can be easily adapted for other metal oxide or ceramic systems by simply changing the precursor.n Graphical abstract