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Developing efficient, stable and sustainable photocatalysts for water splitting is one of the most significant methods for generating hydrogen. Conjugated microporous polymers, as a new type of organic semiconductor photocatalyst, have adjustable bandgaps and high specific surface areas, and can be synthesized using diverse methods. In this work, we report the design and synthesis of a series of pyridyl conjugated microporous polymers (PCMPs) utilizing polycondensation of aromatic aldehydes and aromatic ketones in the presence of ammonium acetate. PCMPs with different chemical structures were synthesized via adjusting monomers with different geometries and contents of nitrogen element, which could adjust the bandgap and photocatalytic performance. Photocatalytic hydrogen evolution rate (HER) up to 1198.9 µmol·h−1·g−1 was achieved on the optimized polymer with a specific surface area of 312 m2·g−1 under UV-Vis light irradiation (λ>320 nm). This metal-free synthetic method provides a new avenue to preparing an efficient photocatalyst for hydrogen evolution.

Azobenzene-based materials have found applications in a wide variety of systems as a convenient method to induce photo-responsive behaviour through facile trans (E) to cis (Z) isomerization. Of particular interest are condensed matter systems, for which diverse assemblies have been applied in myriad ways to produce optical materials, controllable assemblies and functional surfaces. However, isomerization of azobenzene faces unique challenges in condensed systems when compared with dilute states (molecular solution and gas phase) where isomerization is best understood. In the present work, we explore recent studies looking at these challenges experienced in condensed matter phases, some solutions proposed to improve isomerization efficiency, and further give these issues wider context for the future development of light-responsive soft-matter systems.

Fiber-shaped supercapacitors (FSCs) are promising energy storage devices that meet the growing demands for the miniaturization, flexibility and compatibility of wearable electronics. However, when compared with batteries, the low energy density remains the main limitation to practical applications. Conjugated microporous polymer (CMP) network synthesized using Buchwald-Hartwig cross-coupling reactions, featured tailorable porous structures, reversible redox chemistry and demonstrated highly efficient capacitive performance. Herein CMP network grafted on carbon nanotube fibers (CNF@CMP) with high areal specific capacitance (671.9 mF cm-2 at a current density of 1 mA cm-2) were successfully achieved for polytriphenylamine (PTPA)-based network. All-solid-state symmetrical twisted CNF@PTPA FSCs fabricated with PVA/H3PO4 as gel electrolyte exhibited a high specific areal capacitance of 398 mF cm-2 (0.28 mA cm-2), a maximal operating voltage of 1.4 V, and an energy density of 18.33 μWh cm-2. Moreover, they showed excellent flexibility and mechanical stability retaining 84.5% of the initial capacitance after 10000 bending cycles. These materials provide a new route to high-performance wearable supercapacitors (HPWS), with wide potential applications in wearable electronics, as shown by the examples provided.

The formation of colloids with anisotropically patterned surfaces is of growing interest for the creation of hierarchical structures and the templating of nanoparticles. We have recently shown that well-defined two-dimensional platelets with low areal dispersities can be formed by the seeded growth of a blend of homopolymers and block copolymers. Herein we form rectangular platelets containing two block copolymers with different coronal chemistries. On addition of a solvent that is only able to solvate the corona of one block, we were able to form colloidally stable micelles with patterned surfaces via coronal collapse. Scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy and atomic force microscopy were employed to provide information on the structure and size of the patches decorating the micelle surfaces.

The number and type of new supramolecular polymer (SMP) systems have increased rapidly in recent years. Some of the key challenges faced for these novel systems include gaining full control over the mode of self-assembly, the creation of novel architectures and exploring functionality. Here, we provide a critical overview of approaches related to perylene-based SMPs and discuss progress to exert control over these potentially important SMPs through chemical modification of the imide substituents. Imide substitutions affect self-assembly behaviour orthogonally to the intrinsic optoelectronic properties of the perylene core, making for a valuable approach to tune SMP properties. Several recent approaches are therefore highlighted, with a focus on controlling 1) morphology, 2) H- or J- aggregation, and 3) mechanism of growth and degree of aggregation using thermodynamic and kinetic control. Areas of potential future exploration and application of these functional SMPs are also explored.

Dielectrophoresis is the electro-mechanical phenomenon where a force is generated on a dielectric material when exposed to a non-uniform electric field. It has potential to be exploited in smart materials for robotic manipulation and locomotion, but to date it has been sparsely studied in this area. Herein, a new type of dielectrophoretic actuator exploiting a novel electroactive polymer is described, termed as dielectrophoretic elastomer (DPE), which undergoes electric field-driven actuation through dielectrophoresis. Unique deflection and morphing behavior of the elastomer induced by controlling the dielectrophoretic phenomenon, such as out-of-plane deformation and independence of electric field polarity, are illustrated. The dielectric and mechanical properties of the DPE are studied to gain insight into the influence of materials composition on deformation. Actuation performance using different electrode parameters is experimentally investigated with supplementary analysis through finite element simulation, revealing the relationship between electric field inhomogeneity and deflection. The applications of DPE actuators in a range of robotic devices is demonstrated, including a pump, an adjustable optical lens, and a walking robot. This diverse range of applications illustrates the wide potential of these new soft-and-smart electric field-driven materials for use in soft robotics and soft compliant devices.

Porous polyimides (pPIs) represent a fascinating class of porous organic polymers (POPs). Not only do they exhibit high thermal and chemical stabilities, high surface areas, and energy storage capabilities, but their formation relies upon simple polycondensation reactions. A wide library of linker (dianhydrides) and core (amines) starting materials offers a vast range of crosslinked pPIs. This review details and carefully compares the unique properties and functions of both amorphous and crystalline pPIs. Furthermore, their applications in current global challenges in the fields of gas storage and separation, electrical energy storage, catalysis, drug delivery and sensors are reported. Finally, the review highlights the progress of pPIs since 2010 and offers an outlook and suggestions for future areas for exploration and potential applications within the field.

Here we expand our recently reported Bristol–Xi'an Jiaotong (BXJ) approach using simple salts to fine-tune the porosity of conjugated microporous materials synthesized by various reaction approaches, including Buchwald–Hartwig (BH), Sonogashira–Hagihara, oxidative coupling and Suzuki cross-coupling. The surface area and the porosity of the produced conjugated microporous polyanilines (CMPAs) acquired from the non-salt-added BH coupling are optimized by the addition of inorganic salts. BXJ-salt addition provides a facile route to radically improve the BET surface area from 28 to 901 m2 g−1 for PTAPA and from 723 m2 g−1 to 1378 m2 g−1 for PAPA in a controllable manner. In addition, the surface area shows a gradual decrease with an increase in the ionic radius of salts. We furthermore show high compatibility of this approach in the synthesis of typical CMPs, further increasing the surface area from 886 to 1148 m2 g−1, 981 to 1263 m2 g−1, and 35 to 215 m2 g−1 for CMP-1, PTCT and p-PPF, respectively. More importantly, the BXJ approach also allows the broad PSD of the CMPs to be narrowed to the microporous range only, mimicking COFs and MOFs. With the porosity optimized, CO2 uptakes are dramatically improved by >300% from 0.75 mmol g−1 to 2.59 mmol g−1 for PTAPA and from 2.41 mmol g−1 to 2.93 mmol g−1 for PAPA. Careful addressing of Hansen solubility parameters (HSPs) of solvents and resulting polymers through salt addition has the potential to become an important design tool for the preparation of fully tuneable porous materials. We are currently exploring further methods to tune both structure and function in a wide range of organic porous materials.

Simple inorganic salts are used to tune N‐containing conjugated microporous polymers (CMPs) synthesized by Buchwald–Hartwig (BH) cross‐coupling reactions. Poly(triphenylamine), PTPA, initially shows a broad distribution of micropores, mesopores, and macropores. However, the addition of inorganic salts affects all porous network properties significantly: the pore size distribution is narrowed to the microporous range only, mimicking COFs and MOFs; the BET surface area is radically improved from 58 m2 g−1 to 1152 m2 g−1; and variations of the anion and cation sizes are used to fine‐tune the surface area of PTPA, with the surface area showing a gradual decrease with an increase in the ionic radius of salts. The effect of the salt on the physical properties of the polymer is attributed to adjusting and optimizing the Hansen solubility parameters (HSPs) of solvents for the growing polymer, and named the Beijing–Xi'an Jiaotong (BXJ) method.

Colloidal liquid crystals are an emerging class of soft materials that naturally combine the unique properties of both liquid crystal molecules and colloidal particles. Chiral liquid crystal blue phases are attractive for use in fast optical displays and electrooptical devices, but the construction of blue phases is limited to a few chiral building blocks and the formation of blue phases from achiral ones is often counterintuitive. Herein we demonstrate that achiral dumbbell-shaped colloids can assemble into a rich variety of characteristic liquid crystal phases, including nematic phases with lock structures, smectic phase, and particularly experimental observation of blue phase III with double-twisted chiral columns. Phase diagrams from experiments and simulations show that the existence and stable regions of different liquid crystal phases are strongly dependent on the geometrical parameters of dumbbell-shaped colloids. This work paves a new route to the design and construction of blue phases for photonic applications.

To develop ultra-fast charging and long-life lithium ion batteries, a surface-controlled pseudo-capacitive reaction mechanism for high-performance organic lithium ion batteries is developed based on a coaxial nanocomposite of an active anthraquinone-based covalent organic framework (AQ-COF) and carbon nanotubes. AQ-COF was grown on the surface of carbon nanotubes (AQ-COF@CNTs) through in situ polymerization to improve the conductivity and to facilitate electrochemical properties. AQ-COF grown on CNTs exhibited excellent rate performance and was found to retain 76% of its initial capacity at a current density of 5000 mA g−1 (33C), and even retained 48% at an ultra-high current density of 10 000 mA g−1 (66.7C). Furthermore, under long term cycling performance investigations, the AQ-COF@CNT based cathode retained 100% of its initial capacity even after 3000 charge–discharge cycles. We further evaluated the charge storage mechanism and found that pseudocapacitance arising from surface-controlled redox reactions, coupled with excellent charge-transfer properties owing to the conductive CNT network and facilitated by the large surface area of active material, is mainly responsible for this excellent rate and cycling performance.

Polymeric supra-amphiphiles are amphiphiles that are fabricated by linking polymeric segments, or small molecules and polymeric segments, by noncovalent interactions or dynamic covalent bonds. Compared with conventional amphiphilic polymers, polymeric supra-amphiphiles are advantageous in that they possess dynamic features and their preparation may be to some extent more facile. Moreover, polymeric supra-amphiphiles are endowed with richer structure and higher stability compared with small-molecule supra-amphiphiles. Owing to these properties, polymeric supra-amphiphiles have so far shown great promise as surfactants, nanocarriers and in therapies. In this tutorial review, recent work on polymeric supra-amphiphiles, from molecular architectures to functional assemblies, is presented and summarized. Different polymeric supra-amphiphile topologies and related applications are highlighted. By combining polymer chemistry with supramolecular chemistry and colloid science, we anticipate that the study of polymeric supra-amphiphiles will promote the continued development of the molecular engineering of functional supramolecular systems, and lead to practical applications, especially in drug delivery.

We report the formation of near uniform block copolymer fiberlike micelles of controlled length with a crystalline polyselenophene core via the seeded growth process termed living crystallization-driven self-assembly (CDSA). Poly(3-decylselenophene)-block-poly(dimethylsiloxane) (P3DSe-b-PDMS) forms long, fiberlike micelles in selective solvents. Attempts to control the length of these fibers by seeded growth following sonication to form the seeds afforded samples with lengths limited to ca. 300 nm. However, we found that direct dispersion of P3DSe-b-PDMS in diethyl ether yields short and relatively low-dispersity nanofibers (Ln = 41 nm; Lw/Ln = 1.16) which can be used as seeds. In this case, seeded growth led to low-dispersity fibers with length control up to ca. 900 nm. Moreover, we demonstrate that block co-micelles with spatially distinct PDMS and polystyrene (PS) coronal segments can be accessed from the sequential addition of dissolved P3DSe-b-PS to preformed P3DSe-b-PDMS micelles.

An addressable packing parameter approach was developed for reversibly tuning the self-assembly of oligo(aniline)-based supra-amphiphiles., We present a newly developed approach to non-covalently address the packing parameter of an electroactive amphiphile. The pH-responsive reversible switching of a tetra(aniline)-based cationic amphiphile, TANI-pentyl trimethylammonium bromide (TANI-PTAB), between self-assembled vesicles and nanowires by acid/base chemistry in aqueous solution is used to exemplify this approach. Trifluoroacetic acid (TFA) was selected as a prototypical acid to form emeraldine salt (ES) state (TANI(TFA)2-PTAB) vesicles for this new class of small-molecule supramolecular amphiphiles. UV-vis-NIR spectroscopy, transmission electron microscopy (TEM), tapping-mode atomic force microscopy (AFM), and fluorescence spectroscopy were used to investigate the reversible structural transformation from vesicles to nanowires. We show that utilising different protonic acid-dopants for TANI-PTAB can regulate the packing parameter, and thus the final self-assembled structures, in a predictable fashion. We envisage potential application of this concept as smart and switchable delivery systems.

Light-responsive binary (azobenzene + solvent) lyotropic liquid crystals (LCs) were investigated by structural modification of simple azobenzene molecules. Three benzoic acid-containing azobenzene molecules 4-(4-(hydroxyphenyl)diazenyl)benzoic acid (AZO1), 3-(4-(hydroxyphenyl)diazenyl)benzoic acid (AZO2) and 5-(4-(hydroxyphenyl)diazenyl)isophthalic acid (AZO3) were produced with various amide substitutions to produce tectons with a variety of hydrophobicity, size and branching. The LC mesophases formed by binary (azobenzene + solvent) systems with low volatility solvents dimethylsulfoxide (DMSO) and N,N-dimethylformamide (DMF) as well as the protic ionic liquids ethylammonium formate (EAF) and propylammonium formate (PAF), were investigated using a combination of small-angle X-ray and neutron scattering (SAXS and SANS) as well as polarising light microscopy (PLM). Increasing alkyl group length was found to have a strong influence on LC phase spacing, and changes in the position of substitution on the benzene ring influenced the preferred curvature of phases. UV-induced trans to cis isomerization of the samples was shown to influence ordering and optical birefringence, indicating potential applications in optical devices.

Porous organic polymers (POPs) have received great attention worldwide and become attractive for capture and storage of carbon dioxide (CO2) and radioactive iodine (129I or 131I). Here we present modified tetraphenylmethane (TPM)-based POPs i.e. mPTPMs (synthesized via Buchwald-Hartwig cross-coupling of a tetrakis(4-bromophenyl) methane core and selected aryl diamine linkers, followed by a crosslinking alkylation strategy using diiodomethane as a crosslinker). This new strategy offers mPTPMs with high surface areas up to 640 m2/g and uniform ultramicropore size of 0.6 nm, where porous properties are readily controlled by the substitutions of linkers and the crosslinker. Finally, as-synthesized mPTPMs exhibit good CO2 uptake capacities (0.106 g/g at 273 K and 1 bar) and high iodine uptake capacities up to 3.94 g/g within only 2.5 h, representing fast and efficient adsorbents for wider environmental applications.

Organometallic coordination polymers (OMCPs) are a promising class of thermoelectric materials with high electrical conductivities and thermal resistivities. The design criteria for these materials, however, remain elusive and so far material modifications have been focused primarily on the nature of the metal cation to tune the thermoelectric properties. Herein, an alternative approach is described by synthesizing new organic ligands for OMCPs, allowing modulation of the thermoelectric properties of the novel OMCP materials over several orders of magnitude, as well as controlling the polarity of the Seebeck coefficient. Extensive material purification combined with spectroscopy experiments and calculations furthermore reveal the charge‐neutral character of the polymer backbones. In the absence of counter‐cations, the OMCP backbones are composed of air‐stable, ligand‐centered radicals. The findings open up new synthetic possibilities for OMCPs by removing structural constraints and putting significant emphasis on the molecular structure of the organic ligands in OMCP materials to tune their thermoelectric properties., The authors gratefully acknowledge Dr. Mark Baxendale for the use of the MMR Seebeck instrument, as well as Dr. Shibo Xi for the support and assistance provided during the XANES measurements. Z.L., T.L. and J.L. acknowledge the support from Chinese Scholarship Council (CSC). B.C.S. acknowledges funding by the Leverhulme Trust (Grant RF‐2017‐655\4) and the EPSRC (EP/P007767/1). M.A.Z. acknowledges the UK Engineering and Physical Sciences Research Council (EPSRC) for funding (Grant EP/N004884/1, Integration of Computation and Experiment for Accelerated Materials Discovery). B.C.S. and M.A.Z. acknowledge the EPSRC (Grant EP/R034540/1, Defect Functionalized Sustainable Energy Materials: From Design to Devices Application). O.F. acknowledges the support of The Royal Society (UF140372). The authors at ICMAB would like to acknowledge financial support from the Spanish Ministry of Science, Innovation and Universities through the “‘Severo Ochoa”' Program for Centers of Excellence in R&D (SEV‐2015‐0496), PGC2018‐095411‐B‐I00, and MAT2017‐ 90024‐P, and from the European Research Council (ERC) under grant agreement no. 648901. J. P. J. has received financial support through the “la Caixa” INPhINIT Fellowship Grant (Grant code: LCF/BQ/IN17/11620035). L.P. acknowledges a Newton Fellowship from the Royal Society for funding (grant reference NF170361). The use of the UCL Legion, Myriad, and Grace High Performance Computing Facilities (Legion@UCL, Myriad@UCL and Grace@UCL) is acknowledged in the production of this work. Computational work was also performed on the ARCHER UK National Supercomputing Service, via our membership of the UK's HEC Materials Chemistry Consortium, funded by EPSRC (EP/L000202 and EP/R029431), and the UK Materials and Molecular Modelling Hub, which is partially funded by EPSRC (EP/P020194/1).

Four new conjugated microporous polymers (CMPs) were synthesized by a Buchwald-Hartwig (BH) cross-coupling reaction of tri-and tetrafunctionalized precursors to yield materials with tunable surface area and pore size distribution. This approach yielded LPCMP1-4, CMPs with significantly higher Brunauer-Emmett-Teller (BET) surface areas (more than 5 times higher) than other related BH-based CMPs. These CMPs possess not only high BET specific surface areas and high chemical and thermal stabilities, but also exhibit outstanding swellability. To the best of our knowledge, swellable behavior was studied in great detail for CMPs for the first time, with the greatest degree of swelling for methanol reaching 16.5 and 16.3 mL g -1 for LPCMP1 and LPCMP3, respectively. Owing to their excellent swellability, we further studied the adsorption capacity of these CMPs for different toxic organic vapors (including toluene and methanol). LPCMP1 and LPCMP3 adsorbed 124 and 117 mg g -1 toluene, respectively, at saturated vapor pressure. For methanol, the adsorption capacities of LPCMP1 and LPCMP3 were up to 250 and 215 mg g -1, respectively, which are the highest recorded values when compared with published data for CMPs, HCPs, MOFs, and porous carbons. These materials are promising candidates for the removal and elimination of hazardous organic vapors and chemical warfare agents. Moreover, all the polymers show high sensitivity to nitroaromatic explosives. LPCMP2 and LPCMP4 exhibit high selectivity for TNT and may be suitable as new candidates to selectively detect TNT for security or environmental applications.

The solution self-assembly of a heterobimetallic diblock copolymer with a crystallisable poly(ferrocenyldimethylsilane) (PFS) core-forming block and a corona-forming segment featuring a poly(cobaltoceniumethylene) (PCE) based polyelectrolyte/surfactant complex, PFS50-b-[PCE][AOT]50 (AOT = bis(2-ethylhexyl) sulfosuccinate), has been explored. Fiber-like micelles were formed in selective solvents for the Co block, presenting a corona in which every repeat unit bears a charge. We found that key features of the 1D morphologies were dependent on both the polarity of the solvent medium and temperature. In the most polar of the explored solvent media (iPrOH), seeded growth from 1D seeds of PFS50-b-P2VP739 (P2VP = poly(2-vinylpyridine)) yielded tapered B-A-B triblock co-micelles, where the width of the terminal B region derived from PFS-b-[PCE][AOT]n reduced on moving from the interface with the seed to the micelle termini. In addition, ca. 30 % of the micelles featured branching to yield multiple terminal blocks. On reducing the polarity of the solvent medium by the addition of 20% THF, the tapering of the micelles was no longer apparent, and the degree of branching was substantially increased to ca. 100 % of the population. With increased amounts of THF (30 %) the degree of branching reduced dramatically to ca. 3 %. In the least polar medium investigated (1:10 iPrOH:EtOAc), linear triblock co-micelles formed in which the terminal blocks were of consistent diameter, with no evidence for tapering or branching. However, significant unsymmetric growth (i.e. a higher degree of growth from one seed terminus compared to the other) to give non-centrosymmetric A-B diblock co-micelles was detected. Post self-assembly modification by coronal counterion exchange to alter the chemistry and solubility of the corona was also possible.

Conjugated microporous polymers (CMPs) are emerging as an important class of materials, finding application in many fields, with applications in energy storage of current importance and significance. We have here summarized the potential of this class of materials, and progress made in the field of energy storage focusing on supercapacitors, lithium and sodium ion batteries. Owing to the high surface areas of these materials, the unique charge storage processes found in CMPs are discussed, and have provided an overview of how CMPs can enable ultrafast batteries with high energy density. A comparison of CMPs and linear polymers is also provided, providing further guidance on design of active materials. The most important challenges faced by CMPs in the energy storage fields has been analyzed, with possible solutions to some of the problems that are currently faced presented. The hope is that this overview would be an interesting and inspirational read to the researcher community in energy storage.

The oxidation states and doped forms of oligo(aniline)s are readily interconverted, and each state has characteristic UV-vis-NIR absorptions, making this spectroscopic technique ideal for in situ analysis of oligo(aniline) behaviour. However, experimental isolation of some of these states can be challenging and quantitative agreement between experimental and calculated spectra has been poor, making it difficult to identify the exact structure(s) and properties of each state. Here we report a comprehensive study of the UV-vis-NIR spectra of all oxidation states and doped forms of a series of oligo(aniline)s of varying lengths (dimer, tetramer and octamer), using a computationally inexpensive DFT method that is particularly suited to molecules with charge-transfer character. The computational study suggests that doped oligo(aniline)s form mixtures of spin isomers (polaronic and bipolaronic forms) in solution, and we have been able to evaluate and compare the most likely electronic configurations, as well as supporting our insights experimentally, by ESR spectroscopy. This doping approach enables tuning of the spin isomer equilibrium position by varying the concentration of protonic dopant, offering a new pathway to explore the electronic structure of π-conjugated molecules more generally, and opening up new approaches to the design of spintronic materials.

The controlled solution self-assembly of an amphiphilic perylene diimide (PDI), with a hydrophobic perylene core and hydrophilic imide substituents with polydisperse oligo(ethylene glycol) (OEG) tethers is presented. It was possible, by a seeded-growth mechanism, to form colloidally stable, one-dimensional fibres with controllable lengths (from 400 to 1700 nm) and low dispersities (1.19-1.29) via a living supramolecular polymerisation process. Under the solvent conditions used, it was found that molecularly dissolved material (unimer) was present in samples of the fibre-like supramolecular assemblies. The free unimer may be present in a conformationally derived kinetically trapped state and/or may represent a more soluble PDI fraction with longer hydrophilic tethers. Significantly, it was also possible to form segmented supramolecular block copolymers by the addition of PDI unimer to chemically distinct PDI seeds, yielding fibres with controlled lengths. These results represent a significant advance in the ability to form PDI-based supramolecular polymers with precisely controlled lengths and architectures.

In this focus review we aim to highlight an exciting class of materials, electroactive amphiphiles (EAAs). This class of functional amphiphilic molecules has been the subject of sporadic investigations over the last few decades, but little attempt has been made to date to gather or organise these investigations into a logical fashion. Here we attempted to gather the most important contributions, provide a framework in which to discuss them, and, more importantly, point towards the areas where we believe these EAAs will contribute to solving wider scientific problems and open new opportunities. Our discussions cover materials based on low molecular weight ferrocenes, viologens and anilines, as well as examples of polymeric and supramolecular EAAs. With the advances of modern analytical techniques and new tools for modelling and understanding optoelectronic properties, we believe that this area of research is ready for further exploration and exploitation.

Soft electroactive devices such as dielectric elastomer actuators have been the subject of research for several decades. One of the reasons they have not found many industrial applications to date is the challenge of manufacturing such devices cost-effectively. 3D printing is now widely used to cut manufacturing time and cost in many industries, but functional and soft materials for 3D printing are still very limited. Here we present a process that could be used to 3D print functional soft, electroactive devices like dielectric elastomer actuators and sensors. We propose a simple, low-cost 3D printing platform that uses direct ink writing of elastomer composites with low filler loading of carbon-based nanoparticles. These composites allow the deposition of smooth, uniform layers as well as rapid curing of printed materials with UV light. A diode laser is then used to induce a chemical transformation of the elastomer to create conductive patterns for electrodes with arbitrary shapes and high detail. The process is still limited by the low elasticity of the laser induced electrode material but if more suitable materials can be found, this process could dramatically reduce the time, cost and complexity involved in manufacturing dielectric elastomer devices while at the same time greatly increasing the possible geometric and functional complexity of the 3D printed devices.

The influence of processing conditions on the thin film microstructure is a fundamental question that must be understood to improve the performance of solution-processed organic electronic materials. Using grazing-incidence X-ray diffraction, we have studied the structure of thin films of a tetra(aniline)-surfactant complex prepared by drop-casting from five solvents (hexane, chloroform, tetrahydrofuran, dichloromethane and ethanol), selected to cover a range of polarities. We found that the structure, level of order and degree of orientation relative to the substrate were extremely sensitive to the solvent used. We have attempted to correlate such solvent sensitivity with a variety of solvent physical parameters. Of particular significance is the observation of a sharp structural transition in the thin films cast from more polar solvents; such films presented significantly greater crystallinity as measured by the coherence length and paracrystalline disorder parameter. We attribute this higher structural order to enhanced dissociation of the acid surfactant in the more polar solvents, which in turn promotes complex formation. Furthermore, the more polar solvents provide more effective screening of (i) the attractive ionic interaction between oppositely charged molecules, providing greater opportunity for dynamic reorganisation of the supramolecular aggregates into more perfect structures; and (ii) the repulsive interaction between the positively charged blocks permitting a solvophobic-driven aggregation of the aromatic surfaces during solvent evaporation.

As model systems of poly(aniline), oligo(aniline)s have been previously predicted to exist in a number of isomeric forms, with positional, geometric and conformational isomerism possible. Here, monolayers of phenyl and alkyl-chain end-capped tetra(aniline)s in their half-oxidised emeraldine base (EB) state are thermally evaporated in ultra-high vacuum (UHV) conditions. Scanning tunneling microscopy (STM) is then used to directly visualize individual cis/trans isomers. The influence the observed isomerism has on the two-dimensional self-assembly of these conjugated systems is discussed. Gas-phase density functional theory (DFT) calculations are used to corroborate the experimental data, providing optimized structural data that corresponds well to the isomers observed by STM. The proof of the presence of these isomers provides the basis for understanding and gaining insight into the lack of well-defined self-assembled thin films and single crystals from aniline-based materials in their half-oxidised EB state. The assembly behavior and properties of molecular thin films are thus clearly and intractably linked, highlighting the importance of isomerism and material choice for organic thin film applications.

A chiral perylene diimide building block has been prepared based on an amine derivative of the amino acid l‐phenylalanine. Detailed studies were carried out into the self‐assembly behaviour of the material in solution and the solid state using UV/Vis, circular dichroism (CD) and fluorescence spectroscopy. For the charged building block BTPPP, the molecular chirality of the side chains is translated into the chiral supramolecular structure in the form of right‐handed helical aggregates in aqueous solution. Temperature‐dependent UV/Vis studies of BTPPP in aqueous solution showed that the self‐assembly behaviour of this dye can be well described by an isodesmic model in which aggregation occurs to generate short stacks in a reversible manner. Wide‐angle X‐ray diffraction studies (WXRD) revealed that this material self‐organises into aggregates with π–π stacking distances typical for π‐conjugated materials. TEM investigations revealed the formation of self‐assembled structures of low order and with no expression of chirality evident. Differential scanning calorimetry (DSC) and polarised optical microscopy (POM) were used to investigate the mesophase properties. Optical textures representative of columnar liquid–crystalline phases were observed for solvent‐annealed samples of BTPPP. The high solubility, tunable self‐assembly and chiral ordering of these materials demonstrate their potential as new molecular building blocks for use in the construction of chiro‐optical structures and devices.

The noncovalent forces that stabilize protein structures are not fully understood. One way to address this is to study equilibria between unfolded states and α-helices in peptides. Electrostatic forces - which include interactions between side chains, the backbone and side chains, and side chains and the helix macrodipole - are believed to contribute to these equilibria. Here we probe these interactions experimentally using designed peptides. We find that both terminal backbone-side chain and certain side chain-side chain interactions (which include both local effects between proximal charges and interatomic contacts) contribute much more to helix stability than side chain-helix macrodipole electrostatics, which are believed to operate at larger distances. This has implications for current descriptions of helix stability, the understanding of protein folding and the refinement of force fields for biomolecular modeling and simulations. In addition, this study sheds light on the stability of rod-like structures formed by single α-helices, which are common in natural proteins such as non-muscle myosins.

An environmentally friendly method is developed to explore the self-assembly of Ph/NH2-capped tetra(aniline), TANI, nanowires in acidic aqueous media with ultrasonic irradiation. Ultrasonic irradiation is demonstrated to be an effective method to achieve self-assembled thermodynamic equilibrium for nanostructure formation in only 2 minutes. Further assembly, i.e., the formation of thicker TANI nanowires in acidic solution left undisturbed for 96 h without the addition of any organic solvent, is also investigated. The self-assembly behaviour of TANI is studied using FT-IR, Raman, UV-Vis spectroscopy, thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy. Investigations suggest that extra hydrogen bonding associated with the protonation, electrostatic interactions and π–π stacking interaction are important for the self-organization of TANI nanowires. Furthermore, the assembly behaviour of TANI nanowires is dependent on the properties of the dopant, including size and concentration, and reflected in the conductivity of the assembled structures. These results provide insight to understand and tune the self-assembly behaviour of nanostructured oligo(aniline)s in complex dopant-containing systems, and form the basis for further detailed mechanistic studies.

Photo-actuating structures inspired by the chemical sensing and signal transmission observed in sun-tracking leaves have recently been proposed by Dicker et al. The proposed light tracking structures are complex, multicomponent material systems, principally composed of a reversible photoacid or base, combined with a pH responsive hydrogel actuator. New modelling and characterization approaches for pH responsive hydrogels are presented in order to facilitate the development of the proposed structures. The model employs Donnan equilibrium for the prediction of hydrogel swelling in systems where the pH change is a variable resulting from the equilibrium interaction of all free and fixed (hydrogel) species. The model allows for the fast analysis of a variety of combinations of material parameters, allowing for the design space for the proposed photo-actuating structures to be quickly established. In addition, experimental examination of the swelling of a polyether-based polyurethane and poly(acrylic acid) interpenetrating network hydrogel is presented. The experiment involves simultaneously performing a titration of the hydrogel, and undertaking digital image correlation (DIC) to determine the hydrogel’s state of swelling. DIC allows for the recording of the hydrogel’s state of swelling with previously unattained levels of resolution. Experimental results provide both model material properties, and a means for model validation.

The controlled formation of MOF-based superstructures with well-defined nanoscale sizes and exquisite morphologies represents a big challenge, but can trigger a new set of properties distinct from their bulk counterparts. Here we report on the use of a self-assembled organic object to template the first example of a nanoscale metal–organic framework (MOF) with a helical morphology. Two prototypical MOFs (HKUST-1 and MIL-100) were used to exemplify the growth of such materials on supramolecular assemblies. Interestingly, it was found that, dependent on the nature of the precursors, not only could well-defined helical MOF nanotubes be facilely fabricated, but novel helical bundle nanostructures could also be formed. These resultant MOF superstructures show additional optical properties and could be used as precursors for the preparation of chiral nanocarbons.

Nitrogen-rich conjugated microporous polymers (NCMPs) have attracted great attention in recent years owing to their polarity, basicity, and ability to coordinate metal ions. Herein three NCMPs, structurally close to polyaniline, were facilely synthesized via chemical oxidative polymerization between multi-connected aniline precursors. The NCMPs with high N content (11.84 wt%), intrinsic ultramicroporosity (94% activity in Suzuki–Miyaura coupling reactions after six continuous runs.

Photochemical actuation systems, those that employ coupled photo-stimuli and chemical reactions to power and control mechanical motion, have the potential to combine the benefits of precise light driven control with chemical energy storage. Furthermore, these systems are inherently soft, making them ideal for use in the emerging field of soft robotics. However, such systems have received comparatively little attention, perhaps due to the poor cycle life and limited activation time of past systems. Here we address these two challenges by switching from the technique of past systems, that of aqueous photoacid solutions and pH-responsive hydrogel actuators, to one employing organic solvents instead. While this switch of solvents successfully eliminates cycle life constraints and allows for tuning of the activation recovery time it also shifts the relative activation point of the hydrogel actuator in such a way that actuation is no longer observed. Several options for addressing this are discussed, with the prospect of using the lessons learned within to make a more informed selection of a different photoacid compound considered the most feasible. While the exploration of photochemical actuation systems is still in a nascent stage, we have great hope for such systems to form the basis of future smart machines with unique functionality.

Supramolecular polymers have attracted lots of interests in the scientific community; however, developing controllable methods of supramolecular polymerization remains a big challenge. This article reviews some recent developments of methods for supramolecular polymerization from controllable fabrication to living polymerization. Three facile methods with general applicability for controllable fabrication of supramolecular polymers have been established recently: the first method is a self-sorting approach by manipulating ring–chain equilibrium based on noncovalent control over rigidity of monomers; the second is the covalent polymerization from supramonomers formed by noncovalent interactions; and the third is supramolecular interfacial polymerization. More excitingly, living supramolecular polymerization has been achieved by two elegant strategies, including seeded supramolecular polymerization under pathway complexity control and chain-growth supramolecular polymerization by metastable monomers. It is anticipated that this review may provide some guidance for precise fabrication of supramolecular polymers, leading to the construction of supramolecular polymeric materials with controllable architectures and functions.

The principle of control signal amplification is found in all actuation systems, from engineered devices through to the operation of biological muscles. However, current engineering approaches require the use of hard and bulky external switches or valves, incompatible with both the properties of emerging soft artificial muscle technology and those of the bioinspired robotic systems they enable. To address this deficiency a biomimetic molecular-level approach is developed that employs light, with its excellent spatial and temporal control properties, to actuate soft, pH-responsive hydrogel artificial muscles. Although this actuation is triggered by light, it is largely powered by the resulting excitation and runaway chemical reaction of a light-sensitive acid autocatalytic solution in which the actuator is immersed. This process produces actuation strains of up to 45% and a three-fold chemical amplification of the controlling light-trigger, realising a new strategy for the creation of highly functional soft actuating systems.

Micelles formed by the self-assembly of block copolymers in selective solvents have attracted widespread attention and have uses in a wide variety of fields, whereas applications based on their electronic properties are virtually unexplored. Herein we describe studies of solution-processable, low-dispersity, electroactive fibre-like micelles of controlled length from π-conjugated diblock copolymers containing a crystalline regioregular poly(3-hexylthiophene) core and a solubilizing, amorphous regiosymmetric poly(3-hexylthiophene) or polystyrene corona. Tunnelling atomic force microscopy measurements demonstrate that the individual fibres exhibit appreciable conductivity. The fibres were subsequently incorporated as the active layer in field-effect transistors. The resulting charge carrier mobility strongly depends on both the degree of polymerization of the core-forming block and the fibre length, and is independent of corona composition. The use of uniform, colloidally stable electroactive fibre-like micelles based on common π-conjugated block copolymers highlights their significant potential to provide fundamental insight into charge carrier processes in devices, and to enable future electronic applications., The self-assembly of block copolymers to form micelles has been used in applications such as drug delivery and composite reinforcement. Here the authors explore the use of fibre-like micelles of controlled length in the active layer of field-effect transistor devices.

Micelles formed by the self-assembly of block copolymers in selective solvents have attracted widespread attention and have uses in a wide variety of fields, whereas applications based on their electronic properties are virtually unexplored. Herein we describe studies of solution-processable, low-dispersity, electroactive fibre-like micelles of controlled length from π-conjugated diblock copolymers containing a crystalline regioregular poly(3-hexylthiophene) core and a solubilizing, amorphous regiosymmetric poly(3-hexylthiophene) or polystyrene corona. Tunnelling atomic force microscopy measurements demonstrate that the individual fibres exhibit appreciable conductivity. The fibres were subsequently incorporated as the active layer in field-effect transistors. The resulting charge carrier mobility strongly depends on both the degree of polymerization of the core-forming block and the fibre length, and is independent of corona composition. The use of uniform, colloidally stable electroactive fibre-like micelles based on common π-conjugated block copolymers highlights their significant potential to provide fundamental insight into charge carrier processes in devices, and to enable future electronic applications.

Design and synthesis of novel microporous materials have received tremendous attention in both CO2 storage and sequestration (CSS) and electrochemical energy storage (EES). We report molecular design and synthesis of conjugated microporous polycarbazole networks as new precursors for nitrogen enriched porous carbons in a low-cost pathway, using nitromethane as solvent, in which FeCl3 is fully soluble. As-prepared porous carbons exhibit a high nitrogen content (6.1 wt%), ultramicropore size (0.7-1 nm) and large surface area (1280 m2 g-1). As result, these novel nitrogen enriched carbons show highly efficient and reversible CO2 capture (can store 20.4 wt% at 1 bar and 11.1 wt% at 0.15 bar and at 273 K, whilst maintain 100% CO2 uptake capacity after 5 times use). Moreover, they can be applied as electrodes and enable high-performance EES devices with fast charge/discharge rate (8 seconds), high electrochemical capacity (558 F g-1), and good cycle ability (retain 95% capacity after 1000 cycles).

CONSPECTUS: The challenge of constructing soft functional materials over multiple length scales can be addressed by a number of different routes based on the principles of self-assembly, with the judicious use of various noncovalent interactions providing the tools to control such self-assembly processes. It is within the context of this challenge that we have extensively explored the use of an important approach for materials construction over the past decade: exploiting electrostatic interactions in our ionic self-assembly (ISA) method. In this approach, cooperative assembly of carefully chosen charged surfactants and oppositely charged building blocks (or tectons) provides a facile noncovalent route for the rational design and production of functional nanostructured materials. Generally, our research efforts have developed with an initial focus on establishing rules for the construction of novel noncovalent liquid-crystalline (LC) materials. We found that the use of double-tailed surfactant species (especially branched double-tailed surfactants) led to the facile formation of thermotropic (and, in certain cases, lyotropic) phases, as demonstrated by extensive temperature-dependent X-ray and light microscopy investigations. From this core area of activity, research expanded to cover issues beyond simple construction of anisotropic materials, turning to the challenge of inclusion and exploitation of switchable functionality. The use of photoactive azobenzene-containing ISA materials afforded opportunities to exploit both photo-orientation and surface relief grating formation. The preparation of these anisotropic LC materials was of interest, as the aim was the facile production of disposable and low-cost optical components for display applications and data storage. However, the prohibitive cost of the photo-orientation processes hampered further exploitation of these materials. We also expanded our activities to explore ISA of biologically relevant tectons, specifically deoxyguanosine monophosphate. This approach proved, in combination with block copolymer (BCP) self-assembly, very fruitful for the construction of complex and hierarchical functional materials across multiple length scales. Molecular frustration and incommensurability, which played a major role in structure formation in combination with nucleotide assembly, have now become important tools to tune supramolecular structure formation. These concepts, that is, the use of BCP assembly and incommensurability, in combination with metal-containing polymeric materials, have provided access to novel supramolecular morphologies and, more importantly, design rules to prepare such constructs. These design rules are now also being applied to the assembly of electroactive oligo(aniline)-based materials for the preparation of highly ordered functional soft materials, and present an opportunity for materials development for applications in energy storage. In this Account, we therefore discuss investigations into (i) the inclusion and preparation of supramolecular photoactive and electroactive materials; (ii) the exploitation and control over multiple noncovalent interactions to fine-tune function, internal structure, and long-range order and (iii) exploration of construction over multiple length scales by combination of ISA with well-known BCP self-assembly. Combination of ISA with tuning of volume fractions, mutual compatibility, and molecular frustration now provides a versatile tool kit to construct complex and hierarchical functional materials in a facile noncovalent way. A direct challenge for future ISA activities would certainly be the construction of functional mesoscale objects. However, within a broader scientific context, the challenge would be to exploit this powerful assembly tool for application in areas of research with societal impact, for example, energy storage and generation. The hope is that this Account will provide a platform for such future research activities and opportunities.

Conjugated microporous polytriphenylamine networks with surface areas of 530 m2 g−1 were synthesized via Buchwald–Hartwig coupling, resulting in high CO2 uptake (up to 6.5 wt%) and CO2–N2 selectivity (75) at 1 bar and 303 K.

Rectangular platelets formed by the self-assembly of block copolymers in selective solvents are of interest for a range of applications. Recently, we showed that the seeded growth of crystallizable blends of a block copolymer and homopolymer yields well-defined, low area dispersity examples of these two-dimensional (2D) structures. The key feature was the use of the same crystallizable polymer segment in the seed and blend components to enable an efficient homoepitaxial growth process. Herein we demonstrate that this 2D crystallization-driven self-assembly approach can be extended to heteroepitaxial growth by the use of different crystallizable polymers with compatible crystal structures. This allows the formation of well-defined "patchy" rectangular platelets and platelet block comicelles with different core chemistries. The use of scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy provided key information on the spatial location of the components in the resulting assemblies and thereby valuable insight into the 2D heteroepitaxial growth process.

3D printing and actively switchable redox‐active oligo(aniline)‐based materials are combined to create novel tuneable 3D photonic materials. By a direct laser writing process, switchable functional structures with submicrometer features are fabricated. Reversible changes in the refractive index of the written materials are generated with negligible size changes.

The use of ionic self-assembly, a facile non-covalent approach, to access non-conventional block copolymer morphologies, including tetragonal and helical structures, from a combination of polyferrocenylsilane diblock copolymer polyelectrolytes and AOT-based surfactants, is described.

We have prepared a simple star‐shaped oligo(aniline) (TDPB) and characterised it in detail by MALDI‐TOF MS, UV/Vis/NIR spectroscopy, time‐dependent DFT, cyclic voltammetry and EPR spectroscopy. TDPB is part of an underdeveloped class of π‐conjugated molecules with great potential for organic electronics, display and sensor applications. It is redox active and reacts with acids to form radical cations. Acid‐doped TDPB shows behaviour similar to discotic liquid crystals, with X‐ray scattering investigations revealing columnar self‐assembled arrays. The combination of unpaired electrons and supramolecular stacking suggests that star‐shaped oligo(aniline)s like TDPB have the potential to form conducting nanowires and organic magnetic materials.

The effective and safe capture and storage of radioactive iodine (129I or 131I) is of significant importance during nuclear waste storage and nuclear energy generation. Here we present detailed evidence of highly efficient and reversible iodine capture in hexaphenylbenzene-based conjugated microporous polymers (HCMPs), synthesized via Buchwald–Hartwig (BH) cross-coupling of a hexakis(4-bromophenyl)benzene (HBB) core and aryl diamine linkers. The HCMPs present moderate surface areas up to 430 m2 g−1, with narrow pore size distribution and uniform ultra-micropore sizes of less than 1 nm. Porous properties are controlled by the strut lengths and rigidities of linkers, whilst porosity and uptake properties can be tuned by changing the oxidation state of the HCMPs. The presence of a high number of amine functional groups combined with microporosity provides the HCMPs with extremely high iodine affinity with uptake capacities up to 316 wt%, which is, to the best of our knowledge, the highest reported to date. Two ways to release the adsorbed iodine were explored: either slow release into ethanol or quick release upon heating (with a high degree of control). Spectral studies indicate that the combination of microporosity, amine functionality and abundant π-electrons ensured well-defined host−guest interactions and controlled uptake of iodine. In addition, the HCMPs could be recycled whilst maintaining 90% iodine uptake capacity (up to 295%). We envisage wider application of these materials in the facile uptake and removal of unwanted oxidants from the environment.

Two chiral complexes (1-SDS and 1-SDBS) were prepared via the ionic self-assembly of a chiral perylene diimide tecton with oppositely charged surfactants. The effect of surfactant tail architecture on the self-assembly properties and supramolecular structure was investigated in detail using UV–vis, IR, circular dichroism, light microscopy, X-ray diffraction studies, and electron microscopy. The results obtained revealed the molecular chirality of the parent perylene tecton could be translated into supramolecular helical chirality of the resulting complexes via primary ionic interactions through careful choice of solvent and concentration. Differing solvent-dependent aggregation behavior was observed for these complexes as a result of the different possible noncovalent interactions via the surfactant alkyl tails. The results presented in this study demonstrate that ionic self-assembly (ISA) is a facile strategy for the production of chiral supramolecular materials based on perylene diimides. The structure–function relationship is easily explored here due to the wide selection and easy availability of common surfactants.

Photo-actuation, such as that observed in the reversible sun-tracking movements of heliotropic plants, is produced by a complex, yet elegant series of processes. In the heliotropic leaf movements of the Cornish Mallow, photo-actuation involves the generation, transport and manipulation of chemical signals from a distributed network of sensors in the leaf veins to a specialized osmosis driven actuation region in the leaf stem. It is theorized that such an arrangement is both efficient in terms of materials use and operational energy conversion, as well as being highly robust. We concern ourselves with understanding and mimicking these light driven, chemically controlled actuating systems with the aim of generating intelligent structures which share the properties of efficiency and robustness that are so important to survival in Nature. In this work we present recent progress in mimicking these photo-actuating systems through remote light exposure of a metastable state photoacid and the resulting signal and energy transfer through solution to a pH-responsive hydrogel actuator. Reversible actuation strains of 20% were achieved from this arrangement, with modelling then employed to reveal the critical influence hydrogel pKa has on this result. Although the strong actuation achieved highlights the progress that has been made in replicating the principles of biomimetic photo-actuation, challenges such as photoacid degradation were also revealed. It is anticipated that current work can directly lead to the development of high-performance and low-cost solartrackers for increased photovoltaic energy capture and to the creation of new types of intelligent structures employing chemical control systems