Fifty years after the Nobel Prize was awarded to Ziegler and Natta, the transition-metal catalyzed polymerization of olefins remains one of the most important reactions conducted on the industrial scale and the subject of industrial as well as academic research. This introductory article will provide a short historical review of the discovery of catalyzed olefin polymerization by Ziegler, Natta, and others and its development in the years following the Nobel Prize, as well as giving insight into Ziegler-Natta polymerization for the nonspecialist.

The state of Phillips Cr/silica catalyst technology is discussed in this article, including recent advances in the science and also economic and environmental challenges to its continued viability. Although these catalysts have often been described as “mature,” many new innovations have been introduced in the past decade that reduce cost, improve quality, and expand the range of products that can be made. Polymers having unusually high, and low, levels of long-chain branching have been introduced. Several advances in the control of the short-chain branch distribution have also been made. Ways to lower the catalyst costs have been successfully implemented, such that Phillips-type catalysts are still the least expensive in the industry. Finally, new chromium-containing hybrid catalysts have been made that marry attributes from single-site and conventional Cr oxide catalysts.

Polyaniline (PANI)–PbTiO3 composites were prepared by using different inorganic and organic acids by in situ polymerization technique using sodium dodecyl benzene sulfonic acid as a surfactant. The structural analysis was studied by using x-ray diffraction, and it was found that PANI is amorphous in nature. The scanning electron microscopy studies reveal that they are agglomerated and irregular, and size of these grains increase by increasing the amount of PANI with different organic and inorganic acids. The real part of complex permittivity (εʹ) and imaginary part of complex permittivity (εʹʹ) and the real part of the permeability (μ′) are studied at X-band frequency where (εʹ) and (εʹʹ) decreas with increase in frequencies, whereas μ′ increases with increase in X-band frequency and exhibits a maximum value of 0.87 at the resonance frequency of 9–11 GHz of 30 wt% PbTiO3 in PANI matrix. Reflection loss peak of 30 wt% of PANI–PbTiO3 composites is 28.6 dB at 10.8 GHz, which may be attributed to the maximum reflection of the microwave power for the particular doping concentration.

THz-range dielectric spectroscopy and first-principle-based effective-Hamiltonian molecular dynamics simulations were used to elucidate the dielectric response in the paraelectric phase of (Ba, Sr)TiO3 solid solutions. Our analysis suggests a crossover between two regimes: a higher-temperature regime governed by the soft mode only versus a lower-temperature regime exhibiting a coupled soft mode/central mode dynamics. Interestingly, a single model can be used to adjust the THz dielectric response in the entire range of the paraelectric phase. The central peak cannot be discerned anymore in the dielectric spectra when the rate of underlying thermally activated processes exceeds certain characteristic frequency of the system.

Vanadium oxide nanorods (VONRs) and vanadium oxide nanotubes (VONTs) were fabricated by hydrothermal method with the induction of hydroxyl and carboxyl functionalized carbon nanotubes (CNTs). The functionalized CNTs not only facilitate the dispersion of CNTs but also serve as centers for polymerization in the hydrothermal reaction. The formation of (VONRs) and (VONTs) was observed by field emission scanning electron microscopy, transmission electron microscopy, x-ray powder diffraction and Fourier transform infrared spectroscopy tests. Self-assembling nanotubes and nanorods were formed together with the layered structures, but they followed different formation mechanisms. The “Rolling” and “Attaching-Oriented Attachment Growth” mechanisms are proposed to describe the formation of VONRs and VONTs, respectively.

Activated carbon adsorbents with superhigh specific surface areas (SHACs), which are used as adsorbents, were prepared by chemical activation of petroleum coke with potassium hydroxide. We investigated the influence of specific surface area on hydrogen desorption capacity using SHACs with the same pore size distribution, whereas the effect of pore size distribution on hydrogen desorption capacity was studied using SHACs with same specific surface area. Results revealed that hydrogen desorption capacity (N) increased with higher specific surface area (S) of SHAC adsorbents, according to the linear relation: N = k·S + b (k > 0). At 273 K and 9.0 MPa, hydrogen desorption capacity of 20.96 mmol/g (4.02 wt%) was observed on a SHAC adsorbent with a specific surface area of 3348 m2/g. There was a linear relationship between hydrogen desorption capacity and mesopore percentage in SHAC adsorbents, described as: N = k2·Xmic + b (k2 > 0). Hydrogen desorption per unit mesopore surface amounted to 0.72 mmol/m2.

Four acrylate-based networks were developed such that they possessed similar glass transition temperature (~− 37 °C) but varied in material stiffness at room temperature by an order of magnitude (2–12 MPa). Thermo-mechanical and adhesion testing were performed to investigate the effect of elastic modulus on adhesion profiles of the developed samples. Adhesion experiments with a spherical probe revealed no dependency of the pull-off force on material modulus as predicted by the Johnson, Kendall, and Roberts theory. Results obtained using a flat probe showed that the pull-off force increases linearly with an increase in the material modulus, which matches very well with Kendall's theory.

The indentation method of nonlinear viscoelastic materials is investigated through combined numerical and experimental efforts to reveal the correlation between the viscoelastic kernel function and the indentation responses. It is shown that the viscoelastic kernel function of a nonlinear viscoelastic solid with viscous response characterized by a linear rate constitutive equation scales with the normalized relaxation load in an indentation relaxation test. This scaling relation does not depend on the geometry of the indented solid and the profile of the indenter. Therefore, it may serve as a fundamental relation for characterizing the viscoelastic properties of some biological soft tissues and artificial soft materials with regular/irregular surface morphology.

Three-dimensional (3D) chrysanthemum-like carbon nanofiber (CCNF) foam architectures were synthesized on highly porous nickel foam via a one-step ambient pressure chemical vapor deposition process by introducing a mixture of precursor gases (H2 and C2H2). The as-synthesized 3D foam architectures were characterized by scanning electron microscopy and transmission electron microscopy, which demonstrate high porosity and a densely packed nature of the hierarchical carbon nanostructures. Symmetrical electrochemical double-layer capacitors were fabricated using electrodes based on the CCNF foam architectures. Cyclic voltammetry, charge–discharge measurements, and electrochemical impedance spectroscopy were conducted to determine the performance metrics. The supercapacitors (SCs) demonstrate a high areal capacitance of 1.37 F/cm2 (gravimetric specific capacitance: 23.83 F/g), which leads to superior values for per area energy density (0.19 Wh/cm2) and power density (141.77 W/cm2). In addition, capacitance retention of ∼100% over 13,000 charge–discharge cycles demonstrates the high electrochemical stability of this type of carbon nanostructure foam for high areal capacitance SCs.

We report on the successful synthesis of a graphene–carbon nanotube (CNT) hybrid architecture by a parallel chemical vapor deposition (CVD) of the two carbon allotropes. The carbon hybrid is a three-dimensional (3D) nanostructure with tuneable architecture comprising vertically grown CNTs as pillars and a large-area graphene plane as the floor. The formation of CNTs and graphene occurs simultaneously in a single CVD growth that we describe as a synchronous synthesis method. Unique nature of the fabrication approach contributes significantly to the quality and composure of final nanohybrid. Detailed characterization elucidates the cohesive structure and robust contact between the graphene floor and the CNTs in the hybrid structure. The functionality of the synthesized graphene hybrid structure has been demonstrated by its incorporation into a supercapacitor cell. Our fabrication approach provides an attractive pathway for the fabrication of novel 3D hybrid nanostructures and efficient device integration.

Bulk-heterojunction organic photovoltaic (BHJ-OPV) technology promises high efficiency at ultralow cost and weight, with potential for nontraditional applications such as building-integrated photovoltaic (PV). There is a widespread presumption that the complexity of morphology makes carrier transport in OPV irreducibly complicated and, possibly, beyond predictive modeling. However, understanding the complex morphology is important because it not only dictates cell efficiency but also the panel performance and the operating lifetime. In this paper, we derive the fundamental thermodynamic as well as morphology-specific practical limits of BHJ-OPV efficiency and lifetime. We find that performance improvement relies not only on morphology engineering but also on increasing the effective mobility–lifetime (μτ) product, the cross-gap between donor/acceptors, and reducing the series resistance. Even if the OPV fails to achieve the highest efficiency anticipated by the thermodynamic limit, its novel form factor, lightweight, and transparency can make it a commercially viable option for many applications.