Multiscale structural and rheological features of colloidal low-methoxyl pectin solutions and calcium-induced sol-gel transition.

The multiscale structural and rheological features of a series of dilute and semidilute low-methoxyl (LM) pectin solutions and a representative pectin/calcium sol-gel sample were systematically explored using a comprehensive combination of dynamic (DLS) and static light/X-ray scattering (SALS/SLS/SAXS), rheology, and microscopy (OM/SEM) characterizations. The study focused on the rarely explored colloidal aspect of LM pectin solutions and sol-gel transition, in contrast to the polymeric features extensively explored in previous studies. A highly uniform colloid-like, micron-sized agglomerate species was revealed in dilute solutions, with a progressively increased degree of flocculation in the semidilute regime (≥1.

Correlation of the hierarchical structure with rheological behavior of polypseudorotaxane gel composed of pluronic and β-cyclodextrin.

We have identified the hierarchical (primary, secondary, tertiary and quaternary) structures of a polypseudorotaxane (PPR) gel composed of the Pluronic F108 and β-cyclodextrin system to be β-cyclodextrin crystalline, lamellar sheets, lamellar stacks and "grains", respectively. The correlation between the rheological properties and the proposed structures under shear flows was rationalized. Alignment of lamellar stacks and reorganization of grain boundaries under shear flows were investigated by rheo-SANS, small angle X-ray scattering and small-angle light scattering.

Hexagonal Superalignment of Nano-Objects with Tunable Separation in a Dilute and Spacer-Free Solution.

Manipulating building-block nanomaterials to form an ordered superstructure in a dilute and spacer-free solution phase challenges the existing 5-nm node lithography and nanorobotics. The cooperative nature of nanocrystals, polymers, and cells can lead to superarrays or colloidal crystals. For known highly ordered systems, the characteristic length of materials, defined as the shortest dimension of objects, is generally larger than their separations.

Solvent Effects on Morphology and Electrical Properties of Poly(3-hexylthiophene) Electrospun Nanofibers.

Herein, poly(3-hexylthiophene-2,5-diyl) (P3HT) nanofiber-based organic field-effect transistors were successfully prepared by coaxial electrospinning technique with P3HT as the core polymer and poly(methyl methacrylate) (PMMA) as the shell polymer, followed by extraction of PMMA. Three different solvents for the core polymer, including chloroform, chlorobenzene and 1,2,4-trichlorobenzene, were employed to manipulate the morphologies and electrical properties of P3HT electrospun nanofibers. Through the analyses from dynamic light scattering of P3HT solutions, polarized photoluminescence and X-ray diffraction pattern of P3HT electrospun nanofibers, it is revealed that the P3HT electrospun nanofiber prepared from the chloroform system displays a low crystallinity but highly oriented crystalline grains due to the dominant population of isolated-chain species in solution that greatly facilitates P3HT chain stretching during electrospinning.

Solution properties of imidazolium-based amphiphilic polyelectrolyte in pure- and mixed-solvent media.

The solution properties of a synthesized imidazolium-based amphiphilic polyelectrolyte dissolved in pure- and mixed-solvent media composed of two aprotic polar solvents (N,N-dimethylacetamide (DMAc) and N-methyl-2-pyrrolidone (NMP)) having a similar dielectric constant are explored in the semidilute regime (1-4 wt%). Rheological characterizations reveal that the use of mixed-solvent media (e.g.

Scalable Wet Deposition of Zeolite AEI with a High Degree of Preferred Crystal Orientation.

Producing zeolite films with controlled preferred orientation on an industrial scale is a long-standing challenge. Herein we report on a scalable approach to the direct wet deposition of zeolite thin films and membranes while maintaining a high degree of control over the preferred crystal orientation. As a proof of concept, thin films comprising aluminophosphate zeolite AEI were cast on silicon wafer or porous alumina substrates.

Properties of Single-Walled Aluminosilicate Nanotube/Poly(vinyl alcohol) Aqueous Dispersions.

The properties of (synthesized) single-walled aluminosilicate nanotube (AlSiNT; light-scattering characterized length ∼2000 ± 230 nm and diameter ∼35 ± 4 nm) dispersed in an aqueous poly(vinyl alcohol) (PVA) solution (10 wt %) are systematically explored using a comprehensive combination of (polarized/depolarized) dynamic light scattering, rheological, rheo-optical, and scanning electron microscopy analysis schemes. The nanotube/polymer dispersions under investigation are promising for their fair nanotube dispersion in pristine aqueous media (e.g.

Relationships between the solution and solid-state properties of solution-cast low-k silica thin films.

This paper reports on the fabrication of low-k (amorphous) silica thin films cast from solutions without and with two different types of surfactants (TWEEN® 80 and Triton™ X-100) to elucidate the relationships between the structural/morphological features of the casting solutions and the physical properties of the resulting thin films. Cryogenic transmission microscopy (cryo-TEM), static/dynamic light scattering (SLS/DLS), and small-angle X-ray scattering (SAXS) revealed contrasting colloidal dispersion states and phase behavior among the three casting solutions. Casting solution with the Triton™ X-100 surfactant produced stable (>90 days) nanoparticles with good dispersion in solution (mean particle size ∼10 nm) as well as good mesopore volume (characterized by nitrogen physisorption) in powder and thin films of high mechanical strength (characterized by the nanoindentation test).