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This study investigates the formation of amorphous tetravalent metal hydroxides, M(OH)

Short- and long-range correlations between solutes in solvents can influence the macroscopic chemistry and physical properties of solutions in ways that are not fully understood. The class of liquids known as complex (structured) fluids—containing multiscale aggregates resulting from weak self-assembly—are especially important in energy-relevant systems employed for a variety of chemical- and biological-based purification, separation, and catalytic processes. In these, solute (mass) transfer across liquid–liquid (water, oil) phase boundaries is the core function. Oftentimes the operational success of phase transfer chemistry is dependent upon the bulk fluid structures for which a common functional motif and an archetype aggregate is the micelle. In particular, there is an emerging consensus that mass transfer and bulk organic phase behaviors—notably the critical phenomenon of phase splitting—are impacted by the effects of micellar-like aggregates in water-in-oil microemulsions. In this study, we elucidate the microscopic structures and mesoscopic architectures of metal-, water-, and acid-loaded organic phases using a combination of X-ray and neutron experimentation as well as density functional theory and molecular dynamics simulations. The key conclusion is that the transfer of metal ions between an aqueous phase and an organic one involves the formation of small mononuclear clusters typical of metal–ligand coordination chemistry, at one extreme, in the organic phase, and their aggregation to multinuclear primary clusters that self-assemble to form even larger superclusters typical of supramolecular chemistry, at the other. Our metrical results add an orthogonal perspective to the energetics-based view of phase splitting in chemical separations known as the micellar model—founded upon the interpretation of small-angle neutron scattering data—with respect to a more general phase-space (gas–liquid) model of soft matter self-assembly and particle growth. The structure hierarchy observed in the aggregation of our quinary (zirconium nitrate–nitric acid–water–tri-n-butyl phosphate–n-octane) system is relevant to understanding solution phase transitions, in general, and the function of engineered fluids with metalloamphiphiles, in particular, for mass transfer applications, such as demixing in separation and synthesis in catalysis science., Multiscale structure perspectives for zirconium-loaded organic phases show hierarchical aggregation built upon coordination complexes that self-assemble into primary clusters that form superclusters.

We present a method for fabricating photonic crystals (PCs) by polymerization-induced microphase separation of block copolymers (BCPs). Molecular weight of BCP for PCs is so large that it has been difficult for conventional solution casting and annealing methods to complete the microphase separation to form periodically ordered submicron structures. Our method overcomes the difficulty by inducing the microphase separation and transitions during the polymerization, when the molecular weight of the BCPs is small enough for the microphase separation and transitions. The microphase-separated structure is then enlarged while maintaining the self-similarity. We succeeded in fabricating PCs with reflection wavelength λm ≈ 1000 nm and a full width at half-maximum Δλ = 0.05λm by living-radical bulk block copolymerization of poly(methyl methacrylate)-block-polystyrene.

The effect of cesium (Cs) adsorption on the mesoscopic structure of the clay minerals vermiculite and weathered biotite (WB) in suspensions was elucidated by small-angle X-ray scattering (SAXS). The clay minerals form multilayered structures, and the Cs cations (Cs(+)) are strongly adsorbed in the interlayer space of the soil clays, in particular vermiculite and WB. SAXS was used to monitor the relationship between Cs(+) adsorption at the clay interlayers and the structural changes at length scales from 1 to 1000 Å. The variation in the distance between the neighboring clay sheets and the spatial arrangement of the clay sheets with and without Cs(+) were clarified. Our quantitative analyses revealed that the number of stacked layers of pure vermiculite was decreased by Cs(+) addition, whereas that of WB increased. Moreover, the average distance between the neighboring layers of vermiculite in suspension was larger than that of WB, which reflects the different conditions of Cs(+) intercalation. These findings provide fundamental insights that are important for predicting the environmental fate of radioactive Cs in contaminated regions and for developing methods for extracting Cs from soil.

We have investigated the origin of a specific polymerization loci that yielded copolymer particles with a bimodal gel permeation chromatographic profile in the early stage of miniemulsion polymerization of styrene (St) with the polymerizable surfactant N-n-dodecyl-N-2-methacryloyloxyethyl-N,N-dimethylammonium bromide (C12DMAEMA). The formation of particles by miniemulsion polymerization using C12DMAEMA was investigated as a function of the polymerization time (tp) and was compared with that using the nonpolymerizable surfactant cetyltrimethylammonium bromide (CTAB). St was miniemulsified with C12DMAEMA or CTAB and was polymerized with either a water-soluble initiator, 2,2′-azobis(2-amidinopropane) dihydrochloride (V50), or an oil-soluble initiator, 2,2′-azobis(isobutyronitrile) (AIBN), at 60 °C in the presence of polystyrene (PSt) as a hydrophobe. Gel permeation chromatography (GPC) and elemental analysis indirectly predicted two different polymerization loci in the St/C12DMAEMA/V50 polymerization system....

Poly(ethylene glycol)-block-poly(N-isopropylacrylamide) (PEG-b-PNIPAAm) was synthesized by radical polymerization of N-isopropylacrylamide (NIPAAm) from the radically activated chain ends generated...

The phase equilibrium property and structural and dynamical properties of pig cornea were studied by macroscopic observation of swelling behavior, dynamic light scattering (DLS), and small-angle X-ray scattering (SAXS) under various conditions. It was found that the corneal gel collapses into a compact state isotropically or anisotropically depending on the external conditions. The corneal gel collapses uniformly into a compact state at a temperature above 55 degrees C because of the denaturation of collagen, whereas it collapses along an axis parallel to the optic axis with increasing NaCl concentration. Anisotropic deswelling was also observed during desiccation. SAXS measurements revealed that the periodicity of the collagen fiber of the cornea does not change even at higher NaCl concentration, which indicates that hydration and dehydration resulting from changes in salt concentration simply cause swelling and deswelling of the glycosaminoglycan (GAG), which is located between the regular two-dimensional lattices of collagen fibers, which obliges the change in thickness. From observations of the dynamics of light scattered by the corneal gel, intensity autocorrelation functions that revealed two independent diffusion coefficients were obtained. Divergent behavior in the measured total scattered light intensities and diffusion coefficients with varying temperature was observed. That is, a slowing of the dynamic modes accompanied by increased "static" scattered intensities was observed. This is indicative of the occurrence of a phase transition as a function of temperature.

We have studied the dynamics of a morphology transition of domains in a reactive system composed of A−B block copolymer and B monomer, where polymerization occurs at the end of the B subchain of th...

We investigated a simultaneous living anionic polymerization process of isoprene (I) and styrene-d8 (S) in benzene-d6 as a solvent with sec-buthyllithium as an initiator into polyisoprene(PI)-block...

This investigation focused on the self-assembly of poly(N-isopropylacrylamide)-block-poly(ethylene glycol) (PNIPA-block-PEG) in water. A quasi-living radical polymerization technique including a Ce(IV) ion redox system enabled us to prepare block copolymers with relatively narrow molecular weight distributions. We distinguish five regions in the phase diagram: a transparent sol, opaque sol, transparent gel, opaque gel, and syneresis. By examining the extent of changes in the spectroscopic properties of a fluorescence probe, pyrene, as a function of block polymer concentration and/or temperature, we determined the critical association concentration as well as the partition coefficient Kv for pyrene. The spectroscopic properties indicate that the hydrophobicity around the probe starts to increase far below the demixing line of the PNIPA-block-PEG, a remarkable finding which suggests that even in the temperature region below the LCST temperature of a PNIPA block (∼32 °C), this block copolymer provides more ...