Mesoporous thin film architectures are an important class of materials that exhibit unique properties, which include high surface area, versatile surface functionalization, and bicontinuous percolation paths through a broad library of pore arrangements on the 10 nm length scale. Although porosimetry of bulk materials via sorption techniques is common practice, the characterization of thin mesoporous films with small sample volumes remains a challenge. A range of techniques are geared toward providing information over pore morphology, pore size distribution, surface area and overall porosity, but none of them offers a holistic evaluation and results are at times inconsistent. In this work, we present a tutorial overview for the reliable structural characterization of mesoporous films. Three model samples with variable pore size and porosity prepared by block copolymer (BCP) coassembly serve for a rational comparison. Various techniques are assessed side-by-side, including scanning electron microscopy (SEM), atomic force microscopy (AFM), grazing incidence small-angle X-ray scattering (GISAXS), and ellipsometric porosimetry (EP). We critically discuss advantages and limitations of each technique and provide guidelines for reliable implementation.

readily observed in nature, e.g., artificial magnetism, [1] negative refractive index, [2][3][4] epsilon-and-mu-near-zero, [5] light trapping, [6] or low frequency plasmons. [7] Such properties make metamaterials a promising platform to design devices with a wide range of uses for society including super-resolution imaging, [8][9][10] invisibility cloaking, [11][12][13] chemical/ biomolecular sensing, [14][15][16] antennas, [17] or absorbers. [18,19] These new functionalities can be achieved by for example using building blocks (so-called meta-atoms) arranged at length scales that are much smaller than the incident wavelength. [20][21][22] In this review article, we focus on the engineering of the optical properties for metamaterials active in the visible and near-infrared (IR) wavelength range. Structural features should be on length scales significantly smaller than the visible wavelengths (400-750 nm) to avoid

Redox flow batteries (RFBs) based on aqueous organic electrolytes are a promising technology for safe and cost-effective large-scale electrical energy storage. Membrane separators are a key component in RFBs, allowing fast conduction of charge-carrier ions but minimizing the cross-over of redox-active species. Here, we report the molecular engineering of amidoxime-functionalized Polymers of Intrinsic Microporosity (AO-PIMs) by tuning their polymer chain topology and pore architecture to optimize membrane ion transport functions. AO-PIM membranes are integrated with three emerging aqueous organic flow battery chemistries, and the synergetic integration of ion-selective membranes with molecular engineered organic molecules in neutral-pH electrolytes leads to significantly enhanced cycling stability.

The processing of mesoporous inorganic coatings typically requires a high-temperature calcination step to remove organic precursors that are essential during the material assembly. Lowering the fabrication energy costs and cutting back on the necessary resources would provide a greater scope for the deployment in applications such as architectural glass, optical components, photovoltaic cells, and energy storage, as well as further compatibilize substrates with low temperature stability. Organic removal methods based on UV–ozone treatment are increasing in popularity, but concerns remain regarding large-scale ozone generation and usage of mercury-containing UV lamps. To this end, we present a method that relies on non-ozone-generating UV radiation at 254 nm (UV254) and incorporation of small amounts of photocatalytic material in the formulation, here demonstrated with TiO2 nanocrystals. At concentrations as low as 5 wt % relative to the main inorganic aluminosilicate material, the TiO2 nanocrystals catalyze a “cold combustion” of the organic components under UV254 irradiation to reveal a porous inorganic network. Using block copolymer-based co-assembly in conjunction with photocatalytic template removal, we produce well-defined mesoporous inorganic thin films with controlled porosity and refractive index values, where the required processing time is governed by the amount of TiO2 loading. This approach provides an inexpensive, flexible, and environmentally friendly alternative to traditional organic removal techniques, such as UV–ozone degradation and thermal calcination.

Block copolymer-templated gold nanostructured surfaces of high refractive index due to controlled plasmonic nanoparticle shape.