Aggregation of bovine serum albumin upon cleavage of its disulfide bonds, studied by the time-resolved small-angle x-ray scattering technique with synchrotron radiation

2015

We study the shear-induced composite onion phase formation behavior of the nonionic surfactant C 10 E 3 lamellar phases containing colloidal particles. Composite lamellar phase gives rise to the onion phase similar to the free-particle system. Depending on the particle size and concentration, the nonlinear rheology and shear modulus are significantly influenced, while the critical shear rate and onion formation kinetics remains unchanged from those of the free-particle system. Modification of the nonlinear rheology indicates that the colloidal particles assist the onion structure formation so that undulation instability is easily induced by anchoring of membranes on surface of particles. The shear modulus of the composite lamellar and onion phases is reasonably explained by considering the line tension of defects and the effect of polyhedral edge of the onion, respectively.

Section: Methodsmentioning

confidence: 99%

Structural rheology of composite onion phase

2015

“…In birefringence measurement under shear, He-Ne laser (λ = 633 nm) was incident on the sample along the velocity gradient direction and transmitted light was detected by the photodiode. Rheo-SAXS experiments were also performed using synchrotron radiation at beam line BL-10C of the Photon Factory at the Institute of Materials Structure Science of the High Energy Accelerator Research Organization in Tsukuba, Japan [22]. Self-made shear cell with couette geometry, which has the gap of 1 mm, was equipped on the beam line.…”

Section: Methodsmentioning

confidence: 99%

Orientation transition of defective lyotropic triblock copolymer lamellar phase

Yamämoto

2014

We study concentration dependence of the critical shear rate of a layer orientation transition in lyotropic triblock copolymer lamellar phase. Theory predicts that suppression of undulation fluctuation by shear triggers the transition. The critical shear rate at high polymer concentration is in reasonable agreement with theory. However, experimental results at low polymer concentrations show different behavior from the prediction. Violation of the theory is attributed to defective nature of the lamellar phase, in which creation of defects prevents the suppression of the undulation fluctuation.

“…Small angle X-ray scattering (rheo-SaXS) measurement was carried out using synchrotron radiation at beam line BL-10C of the Photon factory at the Institute of materials Structure Science of the High energy accelerator research Organization in tsukuba, Japan [27]. Self-made shear cell with the couette geometry was equipped on the beam line.…”

Section: Sample and Viscometrymentioning

confidence: 99%

Kinetics of the orientation transition in the lyotropic lamellar phase

Yamamoto

2016

Kinetics of the orientation transition in the triblock copolymer lamellar phase is studied by viscometry. We find that the strain-controlled mechanism dominates the transition kinetics. We propose a possible scenario of the orientation transition from the viewpoint of the dislocation dynamics. We could also evaluate the critical shear rate of the orientation transition by assuming the limiting velocity of the dislocations under shear. evaluated value is in good agreement with the experimental observation. the nucleation of the dislocations might be necessary for the orientation transition.