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A hydrogel made of crosslinked clusters of highly branched polymers that has ultralow swelling pressure and that forms in 10 minutes despite its low polymer content functions as an artificial vitreous body for over one year without inducing adverse effects.

Most polymeric materials that show sol-gel transitions are unidirectional and stimuli-responsive systems. Here the authors show a block copolymer solution that undergoes autonomous and periodic sol-gel transitions under constant conditions.

Tissue clearing has revolutionised histology, but limited penetration of antibodies and stains into thick tissue segments is still a bottleneck. Here, the authors characterise optically cleared tissue as an electrolyte gel and apply this knowledge to stain the entirety of thick tissue samples.

A chiral discotic triphenylene derivative spontaneously forms millimetre-sized assemblies with high structural order and fluid-like behaviour.

We report the humidity-responsive volume changes of a poly(N-isopropylacrylamide) (PNIPAAm) gel and bending deformation of a PNIPAAm and poly(N,N-dimethylacrylamide) (PDMAAm) complex gel.

The decomposition process of polystyrene particles dispersed in D₂O was analyzed by in situ small-angle neutron scattering under near critical and supercritical conditions. Upon heating in the subcritical state, the particles were swollen by D₂O because of enhanced miscibility between polystyrene and D₂O. In the supercritical state, the particles were completely degraded and formed monomer- or oligomer-rich domains due to phase separation. The findings and utilized techniques provide essential knowledge about the ways to elucidate the structural change of plastics in sub- and supercritical fluids.

Latex films typically suffer from poor mechanical strength compared to solution-cast latex films. In the present study, to obtain tougher latex films, we investigated the relationship between the mechanical properties and the nanostructures of films prepared at different film-formation temperatures (FFTs), i.e., FFTs above and below the glass-transition temperatures (T_g) of the microspheres. Tensile tests revealed that the films showed the highest fracture energies when the film was formed at a temperature higher than the T_g of the microspheres and followed by annealing.

The network structure evolution of a hexamethylenetetramine-cured novolac-type phenolic resin was investigated using ¹H-pulse NMR spectroscopy, SAXS and WAXS to elucidate the mechanism responsible for the apparent absence of inhomogeneity after curing, in which the inhomogeneity was first observed at the gel point.

The static partial scattering functions for linear and ring random copolymers of type A–B are investigated. In the case of random distribution of monomers, analytic forms can be derived. Monte Carlo simulations are used to make evaluations on biased distributions of monomers. Results show that the number, fraction and distribution of monomers have a significant effect on intensities at sufficiently large scattering angles. The scattering function in molten state is also calculated by random phase approximation.

The elastic properties of Tetra-polyethylene glycol (PEG) gel, four-armed PEG network gel, are studied by simulation for deformation of elastic networks containing defects randomly introduced to the network. This network model well reproduces the experimental results of Tetra-PEG gel. In particular, the stress-strain curve of the gel prepared at chain overlap concentration agrees with that of a regular network without defects. As the defect density increases, the Young’s modulus linearly decreases. The fracture and spatial inhomogeneity of the networks are also investigated by the simulation.

The curing behavior of a novolac resin (NV) cured with hexamethylenetetramine (HMTA) under a two-roll mixing mill process, as well as the influence of an excess amount of HMTA on the curing reaction, were investigated by dynamic light scattering and gel permeation chromatography. The relationships between the number of mixing times, the weight-average molecular weight, hydrodynamic radius and the HMTA amount suggests that structural differences governing the mechanical properties of NV are initiated in the pregel stage.

The static structure of polyrotaxane (PR) possessing a supramolecular structure in which cyclic molecules are threaded into an axial polymer was investigated. Using contrast variation small-angle neutron scattering, the conformation of the axial linear polymer and the alignment of cyclic molecules within the axial polymer in a good solvent were evaluated quantitatively, together with derivation of detailed scattering theory. The entropic origin of the stiffing of PR due to the array of cyclic molecules was also discussed.

Three super-tough gels and their deformation mechanism as revealed by small-angle neutron scattering

The drug release behaviors of gelatin hydrogels prepared with polymers in terms of their rheological properties were evaluated. In the oscillatory strain sweep, gelatin/HPMCP hydrogels showed a higher crossover strain (Tan δ = 1) than gelatin and gelatin/Eudragit^® hydrogels. Thus, gelatin/HPMCP hydrogels had the property of elastic hydrocolloids and tended to keep the platform compared with other sample hydrogels. As a result, the drug release from gelatin/HPMCP hydrogels was delayed compared with other sample hydrogels at pH 1.2.

The mechanism of the heat-induced gelation of ovalbumin (OVA) under acidic conditions and the effect of amphiphilic peptide additives on gelation were investigated using dynamic light scattering (DLS) and small-angle neutron scattering (SANS). The molecular morphology and structure probed by DLS and SANS suggest that the heat-induced gelation of OVA solution forms a phase-separated structure. Heating of the solution of OVA and the peptide resulted in effective distribution of the peptide in the matrix of the heat-induced OVA gels and endowed the gel with increased strength.

Schematic illustration of the structural change of catalyst ink under drying process. For catalyst ink dried to a concentration ratio of four, both the carbon agglomerates size and the Nafion shell thickness become smaller.

Electrospinning (ES) is a technique that can produce nanofiber mats from arbitrary polymers. We prepared actuators consisting of nanofiber mat electrodes and ionic liquid gel using three methods, and examined the effect of the preparation method on actuator performance. The results showed that actuators with nanofiber mat electrodes spun from the lowest spinning solution concentration showed a larger strain against an applied voltage. Furthermore, we prepared two types of actuators with different fiber directions and examined the effect of nanofiber alignment on actuator performance.