Three-dimensional photonic crystals, or periodic materials, that do not allow the propagation of photons in all directions with a wavelength in the visible region have not been experimentally fabricated, despite there being several potential structures and the interesting applications and physics that this would lead to. We show using computer simulations that two structures that would enable a bandgap in the visible region, diamond and pyrochlore, can be self-assembled in one crystal structure from a binary colloidal dispersion. In our approach, these two structures are obtained as the large (Mg) and small (Cu) sphere components of the colloidal analogue of the MgCu(2) Laves phase, whose growth can be selected and directed using appropriate wall patterning. The method requires that the particles consist of different materials, so that one of them can be removed selectively after drying (for example, by burning or dissolution). Photonic calculations show that gaps appear at relatively low frequencies indicating that they are robust and open for modest contrast, enabling fabrication from more materials.

A novel templating method to create 3D bicontinuous structured hybrid electrolytes with improved mechanical properties for all-solid-state lithium batteries.

Bicontinuous, interfacially jammed emulsion gels (bijels) are a class of soft solid materials in which interpenetrating domains of two immiscible fl uids are stabilized by an interfacial colloidal monolayer. Such structures form through the arrest of the spinodal decomposition of an initially single-phase liquid mixture containing a colloidal suspension. With the use of hexalmethyldisilazane, the wetting character of silica colloids, ranging in size and dye content, can be modifi ed for fabricating a novel bijel system comprising the binary liquid ethanediol-nitromethane. Unlike the preceding water-lutidine based system, this bijel is stable at room temperature and its fabrication and resultant manipulation are comparatively straightforward. The new system has facilitated three advancements: fi rstly, we use sub 100 nm silica particles to stabilize the fi rst bijel made from low molecular weight liquids that has domains smaller than ten micrometers. Secondly, our new and robust bijel permits qualitative rheological work which reveals the bijel to be signifi cantly elastic and self healing whilst its domains are able to break, reform and locally rearrange. Thirdly, we encapsulate the ethanediol-nitromethane bijel in Pickering drops to form novel particle-stabilized bicontinuous multiple emulsions that we christen bijel capsules. These emulsions are stimuli responsive -they liberate their contained materials in response to changes in temperature and solvency, and hence they show potential for controlled release applications.

Confocal microscopy and rheology studies of two bijel systems are presented to elucidate relationships between the physicochemical properties of bijels and their ability to be utilized as soft matter templates for materials synthesis. For the first time, the origins of viscoelasticity in these systems are investigated using conventional rheometry and a direct correspondence between the elastic storage modulus, particle loading, and the departure from criticality is observed. Further, the rheological transitions that accompany fluid re‐mixing in bijels are characterized, providing key insights into the synergistic role of interfacial tension and interparticle interactions in mediating their mechanical robustness. Bijels that are predominantly stabilized by interfacial tension are also highly sensitive to gradients in chemical composition and more easily prone to mechanical failure during processing. Despite this increased sensitivity, a modified strategy for processing these more delicate systems is developed and its efficacy is demonstrated by synthesizing a bicontinuous macroporous hydrogel scaffold.

Ultra-high-resolution small-angle X-ray scattering in various colloidal photonic crystals is reported. It is demonstrated that an angular resolution of about two microradians is readily achievable at a third-generation synchrotron source using compound refractive optics. The scheme allows fast acquisition of twodimensional X-ray diffraction data and can be realised at sample-detector separations of only a few metres. As a result, diffraction measurements in colloidal crystals with interplanar spacings larger than a micrometre, as well as determination of the range of various order parameters from the width of the Bragg peaks, are made possible.