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Membranes are among the most promising means of delivering increased supplies of fit-for-purpose water, but membrane fouling remains a critical issue restricting their widespread application. Coupling photocatalysis with membrane separation has been proposed as a potentially effective approach to reduce membrane fouling. However, commonly used materials in photocatalysis limit use of low-cost sources such as sunlight due to their large bandgaps. There are few examples of in situ photocatalytic self-cleaning of membranes, with removal from the filtration system and ex situ illumination being more common. In this work, a visible-light-activated photocatalytic film prepared by nitrogen doping into the lattice of TiO2 is deposited on commercial ceramic membranes via atomic layer deposition. The synergy between membrane separation and redox reactions between organic pollutants and reactive oxygen species produced by the visible-light-activated layer offers a possibility for stable and sustainable membrane operation under in situ solar irradiation.

All-conjugated block copolymers bring together hole- and electron-conductive polymers and can be used as the active layer of solution-processed photovoltaic devices, but it remains unclear how molecular structure, morphology, and electronic properties influence performance. Here, the role of the chemical linker is investigated through analysis of two donor–linker–acceptor block copolymers that differ in the chemistry of the linking group. Device studies show that power conversion efficiencies differ by a factor of 40 between the two polymers, and ultrafast transient absorption measurements reveal charge separation only in block copolymers that contain a wide bandgap monomer at the donor–acceptor interface. Optical measurements reveal the formation of a low-energy excited state when donor and acceptor blocks are directly linked without this wide bandgap monomer. For both samples studied, it is found that the rate of charge recombination in these systems is faster than in poly­mer–polymer and polymer–fullerene blends. This work demonstrates that the linking group chemistry influences charge separation in all-conjugated block copolymer systems, and further improvement of photovoltaic performance may be possible through optimization of the linking group. These results also suggest that all-conjugated block copolymers can be used as model systems for the donor–acceptor interface in bulk heterojunction blends.

A facile approach is reported to process rod-coil block copolymers (BCPs) into highly ordered nanostructures in a rapid, low-energy process. By introducing a selective plasticizer into the rod-coil BCPs during annealing, both the annealing temperature and time to achieve thermodynamic equilibrium and highly ordered structures can be decreased. This process improvement is attributed to enhanced chain mobility, reduced rod-rod interaction, and decreased rod-coil interaction from the additive. The novel method is based on kinetically facilitating thermodynamic equilibrium. The process requires no modification of polymer structure, indicating that a wide variety of desired polymer functionalities can be designed into BCPs for specific applications.

We found that synthetic polymers containing metals and metal centers have experienced rapid growth in the last two decades. Metal-containing polymers and these have an unprecedented role to play in modern high-tech applications including nanomanufacturing, sensing, separation and catalysis. Advancement in synthetic strategies for macromolecules has enabled the synthesis of novel, exotic and use-inspired metallopolymers. Using state-of-the-art design strategies, it is now possible to perform targeted synthesis of macromolecules with varied complexity that contain a range of metal centers either in the backbone or in the side chains of the organic moiety. Moreover, the presence of an inorganic element (metals and metal centers) in organic moieties has led to a number of new physicochemical properties while implementing novel functionality to the polymer matrix. This review covers nanotechnology influenced by distinctive features of metal-containing macromolecular systems, particularly in developing flexible, functional materials.

Physical processes that lead to conversion of light into electrical energy inside photovoltaic devices happen at the nanoscale. Therefore, understanding of electrical properties of photovoltaic materials at this length scale is of paramount importance for improvement of device performance. In this paper, we describe and validate a new framework for high-resolution quantitative measurements of electrical and mechanical properties of compliant materials with sub-100-nm resolution. Previous approaches have generally suffered from uncertainty in the quantitative level of contact between the probe and the material being measured; the methodology presented here overcomes this obstacle. We use the broadly studied ITO/PEDOT:PSS/P3HT:PC61BM system as an example to illustrate variability of chemical composition and electrical properties of the active layer at hundred-nanometers and micrometer length scales. Copyright © 2012 John Wiley & Sons, Ltd.

Selective self-limited interaction of metal precursors with self-assembled block copolymer substrates, combined with the unique molecular-level management of reactions enabled by the atomic layer deposition process, is presented as a promising controllable way to synthesize patterned nanomaterials (e.g., Al{sub 2}O{sub 3} see Figure, TiO{sub 2}, etc.) with uniform and tunable dimensions.

Membranes are recognized as a key component in many environment and energy-related applications, but conventional membranes are challenged to satisfy the growing demand for ever more energy-efficient processes. Janus membranes, a novel class with asymmetric properties on each side, have recently emerged and represent enticing opportunities to address this challenge. With an inner driving force arising from their asymmetric configuration, Janus membranes are appealing for enhancing energy efficiency in a variety of membrane processes by promoting the desired transport. Here, the fundamental principles to prepare Janus membranes with asymmetric surface wettability and charges are summarized, and how they work in conventional and unconventional membrane processes is demonstrated.

Mussel-inspired chemistry has attracted widespread interest in membrane science and technology. Demonstrating the rapid growth of this field over the past several years, substantial progress has been achieved in both mussel-inspired chemistry and membrane surface engineering based on mussel-inspired coatings. At this stage, it is valuable to summarize the most recent and distinctive developments, as well as to frame the challenges and opportunities remaining in this field. In this review, recent advances in rapid and controllable deposition of mussel-inspired coatings, dopamine-assisted codeposition technology, and photoinitiated grafting directly on mussel-inspired coatings are presented. Some of these technologies have not yet been employed directly in membrane science. Beyond discussing advances in conventional membrane processes, emerging applications of mussel-inspired coatings in membranes are discussed, including as a skin layer in nanofiltra-tion, interlayer in metal-organic framework based membranes, hydrophilic layer in Janus membranes, and protective layer in catalytic membranes. Finally, some critical unsolved challenges are raised in this field and some potential pathways are proposed to address them.

Phase-segregated block copolymers have received significant attention in the last decade as enabling materials for future technologies. Their value to nanotechnology derives from the expedient tunability of the size, shape, and periodicity of the self-assembled domains by means of manipulating molecular characteristics. Recently, the potential opportunities for block copolymer applications have been bolstered by new methods, which give fine control over long-range ordering of the microdomain structures. Thin polymer films, by themselves, have limited device applications, but myriad functions can be addressed with hybrid hard/soft matter systems in which the organic layer is used as a scaffold for nanoscale organization of inorganic materials. Of specific interest is the interaction of surfactant-mediated colloidal nanoparticles and diblock copolymer films because the nanocrystal capping molecules can be tailored to exhibit preference for one of the polymer blocks. This hierarchical approach to create ordered nanostructures removes the linear correlation of size and patterning time associated with traditional lithographic techniques by self-assembling the entire surface in parallel. Also, the spatial limits of lithography can be transcended and the approach can potentially be adapted to industrial-scale processing. An alternative approach to the colloidal nanocrystal methodology is to use spherical- or cylindrical-phase diblock copolymers as etch masks to produce self-assembled arrays of nanoscale dots, pillars, or lines composed of various materials. The advantage of our approach is that the length-scale of the final functional material is an order of magnitude smaller than the original polymer domains.

Methylammonium lead iodide (MAPbI3) perovskites are organic–inorganic semiconductors with long carrier diffusion lengths serving as the light-harvesting component in optoelectronics. Through a substitutional growth of MAPbI3 catalyzed by polar protic alcohols, evidence is shown for their substrate- and annealing-free production and use of toxic solvents and high temperature is prevented. The resulting variable-sized crystals (≈100 nm–10 µm) are found to be tetragonally single-phased in alcohols and precipitated as powders that are metallic-lead-free. A comparatively low MAPbI3 yield in toluene supports the role of alcohol polarity and the type of solvent (protic vs aprotic). The theoretical calculations suggest that overall Gibbs free energy in alcohols is lowered due to their catalytic impact. Based on this alcohol-catalyzed approach, MAPbI3 is obtained, which is chemically stable in air up to ≈1.5 months and thermally stable (≤300 °C). This method is amendable to large-scale manufacturing and ultimately can lead to energy-efficient, low-cost, and stable devices.

Membrane fouling is one of the most severe problems restricting membrane separation technology for wastewater treatment. This work reports a photocatalytic nanofiltration membrane (NFM) with self-cleaning property fabricated using a facile biomimetic mineralization process. In this strategy, a polydopamine (PDA)/polyethyleneimine (PEI) intermediate layer is fabricated on an ultrafiltration membrane via a co-deposition method followed by mineralization of a photocatalytic layer consisting of β-FeOOH nanorods. The PDA–PEI layer acts both as a nanofiltration selective layer and an intermediate layer for anchoring the β-FeOOH nanorods via strong coordination complexes between Fe3+ and catechol groups. In visible light, the β-FeOOH layer exhibits efficient photocatalytic activity for degrading dyes through the photo-Fenton reaction in the presence of hydrogen peroxide, endowing the NFM concurrently with effective nanofiltration performance and self-cleaning capability. Moreover, the mineralized NFMs exhibit satisfactory stability under simultaneous filtration and photocatalysis processing, showing great potential in advanced wastewater treatment.

Nanomagnetism encompasses naturally occurring magnetic molecules and clusters as well as artificially structured low-dimensional magnetic materials. Basic research areas include the pursuit of novel interfacial magnetic coupling and spin-transport phenomena and creating new magnetic electronic architectures. In addition to the study of fundamental magnetic phenomena, nanomagnets may in the future form the basis of emerging technologies, such as in ultra-high density data storage media, ultra-strong permanent magnets, and biological and chemical sensing. Herein we highlight materials chemistry contributions to the quest for new magnetic functionalities, including the fabrication of surfactant-mediated magnetic particles and soft matter templates as platforms for hierarchically assembled hybrid magnetic materials. Nanomagnetism is positioned at the frontier between chemistry and magnetism. Devising methods to organize functional magnetic nanostructures draws on the unique strengths of a diverse materials chemistry community.