Search Results (4)

Hierarchical porous N-doped carbon spheres featuring a combination of micropores, mesopores and macropores as well as tuneable properties were synthesised using dopamine as a carbon precursor and triblock copolymers (F127, P123 and F127/P123 composites) as templates via direct polymerisation-induced self-assembly. The structures and textures of these materials were characterised using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N₂ adsorption–desorption isotherm analysis, Fourier-transform infrared spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The sample synthesised at an F127:P123 molar ratio of 1:3 (NCS-FP3) exhibited the highest surface area (463 m²/g) and pore volume (0.27 cm³/g). The hydrophobic/hydrophilic molar ratios of the templates were adjusted to control the morphology of the corresponding micelles and hence the porous structures and morphologies of the carbon spheres, which exhibited high CO₂ capture capacities (2.90–3.46 mmol/g at 273 K and 760 mmHg) because of their developed microporous structures and N doping. Additionally, NCS-FP3 exhibited an outstanding electrochemical performance, achieving a high specific capacitance (328.3 F/g at a current density of 0.5 A/g) and outstanding cycling stability (99.2% capacitance retention after 10,000 cycles). These high CO₂ capture and electrochemical performances were ascribed to the beneficial effects of pore structures and surface chemistry features. Full article

Steroid-based liquid crystal polymers and co-polymers have come a long way, with new and significant advances being made every year. This paper reviews some of the recent key developments in steroid-based liquid crystal polymers and co-polymers. It covers the structure–property relationship between cholesterol and sterol-based compounds and their corresponding polymers, and the influence of chemical structure and synthesis conditions on the liquid crystalline behaviour. An overview of the nature of self-assembly of these materials in solvents and through polymerisation is given. The role of liquid crystalline properties in the applications of these materials, in the creation of nano-objects, drug delivery and biomedicine and photonic and electronic devices, is discussed. Full article

Nature as the ultimate inspiration can direct, gate, and selectively transport species across channels to fulfil a specific targeted function. Harnessing such precision over local structure and functionality at the nanoscale is expected to lead to indispensable developments in synthetic channels for application in catalysis, filtration and sensing, and in drug delivery. By combining mesoporous materials with localised charge-switchable poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes, precisely controlling pore filling and exploring the possibility of incorporating two different responsive polymers, we hope to approach the precision control of natural systems in the absence of an external force. Here, we report a simple one-step approach to prepare a mesoporous silica thin film with ~8 nm pores functionalised with a photoiniferter by combining sol–gel chemistry and evaporation-induced self-assembly (EISA). We show that surface-initiated photoiniferter-mediated polymerisation (SI-PIMP) allows the incorporation of a high polymer content up to geometrical pore blocking by the simple application of UV light in the presence of a monomer and solvent, proceeding in a controlled manner in pore sizes below 10 nm, with the potential to tune the material properties through the formation of surface-grafted block copolymers. Full article

Thermoresponsive gelling materials constructed from natural and synthetic polymers can be used to provide triggered action and therefore customised products such as drug delivery and regenerative medicine types as well as for other industries. Some materials give Arrhenius-type viscosity changes based on coil to globule transitions. Others produce more counterintuitive responses to temperature change because of agglomeration induced by enthalpic or entropic drivers. Extensive covalent crosslinking superimposes complexity of response and the upper and lower critical solution temperatures can translate to critical volume temperatures for these swellable but insoluble gels. Their structure and volume response confer advantages for actuation though they lack robustness. Dynamic covalent bonding has created an intermediate category where shape moulding and self-healing variants are useful for several platforms. Developing synthesis methodology—for example, Reversible Addition Fragmentation chain Transfer (RAFT) and Atomic Transfer Radical Polymerisation (ATRP)—provides an almost infinite range of materials that can be used for many of these gelling systems. For those that self-assemble into micelle systems that can gel, the upper and lower critical solution temperatures (UCST and LCST) are analogous to those for simpler dispersible polymers. However, the tuned hydrophobic-hydrophilic balance plus the introduction of additional pH-sensitivity and, for instance, thermochromic response, open the potential for coupled mechanisms to create complex drug targeting effects at the cellular level. Full article