The structure of temperature-sensitive poly(N-isopropylacrylamide) microgels in dilute suspension was investigated by means small-angle neutron scattering. A direct modeling expression for the scattering intensity distribution derived which describes very well experimental data at all temperatures over an extensive q range. overall particle form as internal microgel network is described model. influence temperature, cross-linking density, and size on revealed radial density profiles clearly...

Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation H. M. Laun, R. Bung, S. Hess, W. Loose, O. K. Hahn, E. Hädicke, Hingmann, F. Schmidt, P. Lindner; Rheological small angle neutron scattering investigation of shear‐induced particle structures concentrated polymer dispersions submitted to plane Poiseuille Couette flowa). J. Rheol. 1 May 1992; 36 (4): 743–787....

The characteristic length scales of the structure and fractal behavior a thixotropic colloidal suspension synthetic clay were studied by using combination small-angle neutron x-ray scattering static light scattering. At same time, macroscopic mechanical at rest was characterized means rheometric measurements. Two detected in these yield stress suspensions discotic texture. first, measuring several tens nanometres, is linked to dimension 3. second, order 1 \ensuremath{\mu}m, $D$ that...

The structure and interparticle interactions in colloidal dispersions of montmorillonite Laponite RD (a model hectorite-type clay) have been investigated by small-angle neutron scattering (SANS). Measurements made under static conditions during shear, using a Couette-type cell, for concentrations the range (5 × 10–3)–(6.5 10–2) g cm–3, where time-dependent gelation thixotropic behaviour occur. It is shown that low ionic strength ( < 10–3 mol dm–3) spatial orientational correlations between...

Polymer concentration correlations in a network swollen by solvent are studied small-angle neutron scattering. The is made statistical cross-linking of long chains solution. At small scattering vectors, the intensity strongly increases upon swelling. Upon stretching, unusually oriented isointensity lines (``butterflies'') observed. These effects well described model fractal heterogeneities giving rise to nonhomogeneous swelling or deformation.

The pH-induced release of hydrophilic dyes from poly(2-vinylpyridine-b-ethylene oxide) (P2VP−PEO) block copolymer vesicles is investigated. structure the characterized using small-angle neutron scattering (SANS) and cryo-electron microscopy (cryo-TEM). A decrease pH below 5 leads to protonation dissolution poly-2-vinylpyridine blocks which induces rupture vesicle membrane. Details rupture, dissolution, process are studied by fluorescence video microscopy, gel electrophoresis,...

We report on hollow shell-shell nanogels with two polymer shells that have different volume phase transition temperatures. By means of small angle neutron scattering (SANS) employing contrast variation and molecular dynamics (MD) simulations we show nanocontainers are ideal systems for controlled drug delivery: The temperature responsive swelling the inner shell controls uptake release, while thermoresponsive outer size void colloidal stability. At temperatures between 32 °C < T 42 °C,...

The analysis of small- and ultra-small-angle neutron scattering data for sedimentary rocks shows that the pore-rock fabric interface is a surface fractal $({D}_{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2.82)$ over 3 orders magnitude length scale 10 in intensity. dimension scatterer size obtained from scanning electron microscopy image processing are consistent with data.

We report on a first-order isotropic-to-nematic phase transition induced by shear in concentrated solutions of elongated flexible wormlike micelles. As is applied to disordered micellar solution, the shows up steady-shear experiments as kink stress behaviour. Using small-angle neutron scattering under shear, we show that beyond rate, nematic manifests itself growth crescentlike patterns direction perpendicular flow. A dynamical diagram finally proposed for this system equilibrium polymers.

We report here the experimental results on first-order isotropic to nematic phase transition induced by shear in a concentrated micellar solution of cetyltrimethylammanium bromide (CTAB) without salt. use and compare obtained under same with help four different techniques: rheology (stress rate controlled), flow birefringence (FB), small-angle neutron scattering (SANSUS). The system salt studied is model system. rheological data show that stress \ensuremath{\sigma}, as function rate, allows...

The structure of charged spherical block copolymer micelles in aqueous solution was investigated with static and dynamic light scattering, small-angle neutron cryo-electron microscopy as a function added salt. At low salt concentration the polyelectrolyte shell has typical features an osmotic brush. If exceeds intrinsic ionic strength shell, micellar aggregation number increases due to screening repulsive interaction between chains (salted brush). relation follows simple Donnan equilibrium....

Apolar organic suspensions of rodlike cellulose whiskers modified by a surfactant are investigated small angle neutron scattering. Guinier and Porod analyses performed to characterize the increase cross-sectional radius gyration observed between aqueous whiskers. In addition, comparison with theoretical curves for fibers homogeneous rectangular cross sections finally leads typical dimensions ca. 120 × 210 Å2 in solutions while those water have 88 180 sizes. It is concluded that coated layer...

Pushing the limits: A 200×106 Da structurally defined, linear macromolecule (PG5) has a molar mass, cross-section dimension, and cylindrical shape that are comparable to some naturally occurring objects, such as amyloid fibrils or certain plant viruses. The is resistant against flattening out on surface; picture shows PG5 embracing tobacco mosaic virus (TMV). Detailed facts of importance specialist readers published "Supporting Information". Such documents peer-reviewed, but not copy-edited...

Magnetic nanoparticles have been assembled into the bilayer membrane of block copolymer vesicles. The decorate hydrophobic/hydrophilic interface, which leads to bridging adjacent bilayers and formation oligo-lamellar nanoparticle uptake vesicles is sufficiently high become magnetophoretic in external magnetic fields as shown by video microscopy.

We present a study of equilibrium chain-exchange kinetics well-defined model system for starlike polymeric micelles. The results show that the follows logarithmic time dependence. same feature has been confirmed two other micellar systems. This is in sharp contrast to theoretical predictions and hints towards strongly coupled chain dynamics within cores induced by geometrical constraints.

Topological polymer networks with sliding cross-link points, the "sliding gels" (also called slide-ring gels), are a new class of supramolecular based on intermolecularly cross-linked α-cyclodextrins/poly(ethylene glycol) polyrotaxane precursors. The points such not fixed but can slide along template chain polyrotaxanes. main parameters governing gel properties number cyclodextrins per polyrotaxane, cross-linking density, and nature swelling solvent. Small-angle neutron scattering,...

A detailed study of the dynamical and structural aspects cold crystallization behavior highly flexible poly(dimethylsiloxane)(PDMS) is presented. In order to understand complete behavior, before, under after crystallization, a wide range experimental techniques have been employed. particular emphasis made on interplay between effects how properties amorphous phase evolve during crystallization. This highlighted by combining mobility sensitive techniques, involving broadband dielectric...

A set of random copolymers based on a benzene-1,3,5-tricarboxamide functional methacrylate (BTAMA) and oligoethylene glycol (oEGMA) with different degrees polymerization (DP, from 110 to 450) 10 mol % loading BTAMA were prepared using RAFT polymerizations. The pendant BTA units encode for the formation helical aggregates via 3-fold hydrogen bonding while side chains provide solubility in water. characterized size exclusion chromatography, 1H NMR spectroscopy, circular dichroism light...

The cononsolvency effect on the swelling of different stimuli-sensitive microgels was investigated in water/methanol mixtures. Poly(N,N-diethylacrylamide) (PDEAAM) and poly(N-isopropylacrylamide) (PNIPAM) homopolymer microgels, a PDEAAM-core−PNIPAM-shell microgel, poly(N,N-diethylacrylamide-co-N-isopropylacrylamide) (P(DEAAM−NIPAM)) microgel have been synthesized. core−shell copolymer similar compositions; PDEAAM core particle contributes 80% to total mass, consists 75% DEAAM 25% PNIPAM....

We report on the size, shape, structure, and interactions of lysozyme in ternary system lysozyme/DMSO/water at low protein concentrations. Three structural regimes have been identified, which we term “folded” (0 < φDMSO 0.7), “unfolded” (0.7 ≤ 0.9), “partially collapsed” (0.9 1.0) regime. Lysozyme resides a folded conformation with an average radius gyration 1.3 ± 0.1 nm for 0.7 unfolds (average Rg 2.4 nm) above > 0.7. This drastic change protein’s size coincides loss characteristic tertiary...

We propose a theory for the effective interaction between soft dendritic molecules that is based on shape of monomer density profile macromolecules at infinite dilutions. By applying Flory-type arguments and making use experimentally measured profiles, we derive Gaussian whose parameters are determined by size number dendrimers derived from small-angle neutron scattering (SANS) measurements. this to concentrated dendrimer solutions calculate theoretical structure factors compare them with...