A small‐angle X‐ray scattering study of bromine‐containing latex particles

Bianco, Havazelet; Narkis, M.; Cohen, Yachin

doi:10.1002/(sici)1099-0488(19961130)34:16<2775::aid-polb11>3.3.co;2-n

Cited by 4 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The fitting of this model to the experimental SAXS data was preformed using a minimum least-squares error procedure keeping a constant value of ρ w = 333.3 e/nm 3 for the electron density of water . The inner radius was assumed to be normally distributed.…”

Section: Resultsmentioning

confidence: 99%

“…Modeling of Small-Angle Scattering Intensities. The scattering intensity of a monodisperse system of particles of identical shape can be described as where N is the number of particles per unit volume, S ( q ) is the structure factor, and P ( q ) is the form factor of the object defined as 〈| F 2 ( q )|〉 where F ( q ) is the form factor amplitude defined as …”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Self-Assembly of Model DNA-Binding Peptide Amphiphiles

et al. 2005

View full text Add to dashboard Cite

Peptide amphiphiles combine the specific functionality of proteins with the engineering convenience of synthetic amphiphiles. These molecules covalently link a peptide headgroup, typically from an active fragment of a larger protein, to a hydrophobic alkyl tail. Our research is aimed at forming and characterizing covalently stabilized, self-assembled, peptide-amphiphile aggregates that can be used as a platform for the examination and modular design and construction of systems with engineering biological activity. We have studied the self-assembly properties of a model DNA-binding amphiphile, having a GCN4 peptide as the headgroup and containing a polymerizable methacrylic group in the tail region, using a combination of small-angle X-ray scattering, small-angle neutron scattering, and cryo- transmission electron microscopy. Our results reveal a variety of morphologies in this system. The peptide amphiphiles assembled in aqueous solution to helical ribbons and tubules. These structures transformed into lamella upon DNA binding. In contrast with common surfactants, the specific interaction between the headgroups seems to play an important role in determining the microstructure. The geometry of the self-assembled aggregate can be controlled by means of adding a cosurfactant. For example, the addition of SDS induced the formation of spherical micelles.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Self-Assembly of Model DNA-Binding Peptide Amphiphiles

et al. 2005

View full text Add to dashboard Cite

show abstract

“…The scattering intensity of a monodisperse system of particles of identical shape can be described as 47,48…”

Section: Modeling Of Small Angle Scattering Intensitiesmentioning

confidence: 99%

Distribution of guest molecules in Pluronic micelles studied by double electron electron spin resonance and small angle X-ray scattering

Ruthstein

Raitsimring

Bitton

et al. 2009

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

Pulse double electron-electron spin resonance (DEER) measurements were applied to characterize the distribution and average number of guest-molecules (in the form of spin-probes) in Pluronic P123 micelles. Two types of spin-probes were used, one of which is a spin-labeled P123 (P123-NO), which is similar to the micelles constituent molecules, and the other is spin-labeled Brij56 (Brij56-NO) which is significantly different. Qualitative information regarding the relative location of the spin-labels within the micelles was obtained from the isotropic hyperfine coupling and the correlation times, determined from continuous wave EPR measurements. In addition, complementary small angle X-ray scattering (SAXS) measurements on the P123 micellar solutions, with and without the spin-probes, were carried out for an independent determination of the size of the core and corona of the micelles and to ensure that the spin-probes do not alter the size or shape of the micelles. Two approaches were used for the analysis of the DEER data. The first is model free, which is based on the determination of the leveling off value of the DEER kinetics. This provided good estimates of the number of radicals per micelle (low limit) which, together with the known concentration of the P123 molecules, gave the aggregation number of the P123 micelles. In addition, it provided an average distance between radicals which is within the range expected from the micelles' size determined by SAXS. The second approach was to analyze the full kinetic form which is model dependent. This analysis showed that both spin-labels are not homogeneously distributed in either a sphere or a spherical shell, and that large distances are preferred. This analysis yielded a slightly larger occupation volume within the micelle for P123-NO than for Brij56-NO, consistent with their chemical character.

show abstract

“…The scattering intensity from a dilute system of particles of identical shape (which is overall isotropic) can be regarded as the sum of the intensities scattered by the individual particles. In the most general form, the total scattering intensity per unit volume of sample i ( h ), normalized to the scattering intensity of a single electron, is given by − where φ is the volume fraction of the particles in the sample, f v ( R ) d R is the volume of particles having a size between R and R + d R per total volume of particles, F ( h , R ) is the structure factor of a single particle having size R and volume V 0 ( R ): where F *( h , R ) is its complex conjugate, ρ( r ) is the local electron density, and 〈 〉 represents averaging over all possible orientations.…”

Section: Modeling Of the Saxs Intensitiesmentioning

confidence: 99%

“…) homogeneous part of the scattering curve in polydispersed systems is given by 14,16 where Φ(hR) is the shape factor:…”

Section: 〈F Jmentioning

confidence: 99%

Inner Structure of Inhomogeneous Copolymer Latex Particles

1997

Self Cite

View full text Add to dashboard Cite

A small-angle X-ray scattering (SAXS) study of a model copolymer latex, composed of styrene and pentabromobenzyl acrylate (PBBA, 40 wt %), is presented. The contrast variation method employed in this study was shown to be a sensitive probe for inhomogeneity in the particles. The separation of the homogeneous function allows direct calculation of the size distribution of the spherical particles (volume average diameter, 26.7 ± 1.3 nm). The SAXS analysis reveals a particle's inner structure described as a continuos copolymer phase, of composition being slightly richer in PBBA, within which domains of polystyrene are randomly distributed. The volume fraction of the polystyrene domains was estimated as 11 vol % and their characteristic length as 5.1 nm.

show abstract

A small‐angle X‐ray scattering study of bromine‐containing latex particles

Cited by 4 publications

References 0 publications

Self-Assembly of Model DNA-Binding Peptide Amphiphiles

Self-Assembly of Model DNA-Binding Peptide Amphiphiles

Distribution of guest molecules in Pluronic micelles studied by double electron electron spin resonance and small angle X-ray scattering

Inner Structure of Inhomogeneous Copolymer Latex Particles

Contact Info

Product

Resources

About