Determination of the degree of swelling and crosslinking of latex particles by analytical ultracentrifugation

Müller, H. G.; Schmidt, A.; Kranz, D.

doi:10.1007/bfb0115009

Cited by 13 publications

(4 citation statements)

References 10 publications

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“…AUC Measurements. AUC measurements can be used to access the soluble fraction as well as the degree of swelling of nanogels . The soluble fraction can easily be determined as it is washed out of the microgels upon sedimentation.…”

Section: Resultsmentioning

confidence: 99%

Preparation and Characterization of Photo-Cross-Linked Thermosensitive PNIPAAm Nanogels

Kuckling

Adler

et al. 2006

Macromolecules

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Thermosensitive nanogels were prepared from photo-cross-linkable copolymers of N-isopropylacrylamide (NIPAAm) and 2-dimethylmaleinimido ethylacrylamide (DMIAAm). The colloidal nanogels were formed by UV-irradiated solutions of thermosensitive polymers in water at 45 °C. The size of nanogels could be controlled by the concentration of photopolymer solutions, the amount of chromophore DMIAAm in the photopolymer chains, and sodium dodecyl sulfate (SDS) concentrations. Analytical ultracentrifugation could reveal the degree of swelling of the different nanogel preparations, confirming the data from dynamic light scattering. In addition, the quantitative determination of un-cross-linked polymer species was possible. Even the determination of the degree of swelling distribution was reported for a nanogel for the first time. Hydrogel particles could be prepared with low SDS concentration or even in the absence of a surfactant. Therefore, the effects on swelling produced by the addition of alcohols to these nanogels could be investigated, excluding the influence of SDS on the swelling behavior of these nanogels.

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Section: Resultsmentioning

confidence: 99%

Preparation and Characterization of Photo-Cross-Linked Thermosensitive PNIPAAm Nanogels

Kuckling

Adler

et al. 2006

Macromolecules

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“…The completely redispersed sample C5X-P, that is, the dispersion in THF, was used to check by means of AUC as described in ref whether the particles are entirely cross-linked or still contain free polymer molecules. The sedimentation coefficient distribution given in Figure clearly shows that both the dispersion in THF, which is a good solvent for polystyrene, and the particles contain obviously no single polymer chains as in the range below 300 Sv no sedimentation is detected.…”

Section: Resultsmentioning

confidence: 99%

“…Typically, free polymer molecules have sedimentation coefficients clearly below 10 Sv (cf. ref ). This is an interesting result as it proves that the cross-linking efficiency under compartmentalized reaction conditions is much higher than in homogeneous systems as for styrene bulk polymerization with PEGAM400 at 70 °C no gel fraction was formed at m I values below 5%…”

Section: Resultsmentioning

confidence: 99%

“…Analytical ultracentrifugation (AUC) was performed for cross-linked polymer samples dispersed in tetrahydrofuran with a preparative Optima XL-80K ultracentrifuge (Beckman Coulter, Palo Alto, CA) converted to an analytical one as described in refs and . AUC was used to check whether the particles are entirely cross-linked or still contain free polymer molecules employing a procedure as described in ref . Preparative ultracentrifugation (30 min at 50 000 rpm) (PUC) with a L-70 ultracentrifuge with a 70-Ti rotor (Beckman Coulter, Palo Alto, CA) was used in order to separate the polymer particles in the original latexes from the serum and the dissolved reaction products mainly surfactants and unreacted PEGA400 or PEGAM400 as well as primary recombination products thereof.…”

Section: Experimental Datamentioning

confidence: 99%

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Reactive Poly(ethylene glycol)s in Aqueous Radical Heterophase Polymerization

Tauer

Yıldız

2003

Macromolecules

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A comprehensive study is presented of aqueous heterophase polymerization of styrene with two kinds of reactive poly(ethylene glycol)s, each with an average molecular weight of the poly(ethylene glycol) units of 400 g mol -1 : symmetrical poly(ethylene glycol)-azo-initiators with either terminal hydroxyl or styryl groups. Two kinds of stabilizers have been employed either sodium dodecyl sulfate or cetyltrimethylammonium bromide. Results are presented with regard to polymerization kinetics (reaction calorimetry), average particle sizes (dynamic light scattering), molecular weights (size exclusion chromatography), particle morphologies (transmission electron microscopy), swelling ratios (in water and tetrahydrofuran), and cross-linking density (analytical ultracentrifugation). These results reveal the exciting possibilities of reactive poly(ethylene glycol)s in heterophase polymerization.

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Determination of Particle Size, Core and Shell Size Distributions of Core–Shell Particles by Analytical Ultracentrifugation

Schmidt

Linders

Mayer

et al. 2021

Part & Part Syst Charact

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In core–shell nanoparticle analysis, the determination of size distributions of the different particle parts is often complicated, especially in liquid media. Density matching is introduced as a method for analyzing core–shell nanoparticles using Analytical Ultracentrifugation (AUC), making it possible to obtain the core size distribution in liquid dispersions. For this approach, the density of the dispersion is adjusted to the density of the shell. Oil filled nanocapsules are utilized with component densities of around 1 g mL−1 to demonstrate this technique. The shell size distribution is calculated supposing the particle size distribution as a convolution of the shell‐ and core size distributions. Finally, the distributions of core size, shell thickness, particle size, and particle density and thus particle composition are obtained. To clarify the effect of swelling, AUC measurements are combined with further size characterization methods like Particle Tracking Microscopy and Dynamic Light Scattering.

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Determination of the degree of swelling and crosslinking of latex particles by analytical ultracentrifugation

Cited by 13 publications

References 10 publications

Preparation and Characterization of Photo-Cross-Linked Thermosensitive PNIPAAm Nanogels

Preparation and Characterization of Photo-Cross-Linked Thermosensitive PNIPAAm Nanogels

Reactive Poly(ethylene glycol)s in Aqueous Radical Heterophase Polymerization

Determination of Particle Size, Core and Shell Size Distributions of Core–Shell Particles by Analytical Ultracentrifugation

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