Characterization of Turbid Colloidal Suspensions Using Light Scattering Techniques Combined with Cross-Correlation Methods

Urban, Claus; Schurtenberger, Peter

doi:10.1006/jcis.1998.5769

Cited by 208 publications

(139 citation statements)

References 14 publications

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“…Scattered intensities corrected for multiple scattering were then obtained following established procedures using the reduction in signal intercept as a measure of the degree of multiple scattering. 27 To set the static scattering curve on an absolute scale, the detectors were calibrated by a toluene reference measurement. The transmission, measured with a power meter (PM100 from Thorlabs), was used to correct for the loss of singly scattered intensity in turbid samples.…”

Section: Methodsmentioning

confidence: 99%

The pH Induced Sol−Gel Transition in Skim Milk Revisited. A Detailed Study Using Time-Resolved Light and X-ray Scattering Experiments

et al. 2010

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We present a detailed study of the evolution of the size, structure and stability of casein micelles upon acidification of skim milk typically applied in yogurt-making processes using a combination of time-resolved light and small-angle X-ray scattering experiments. While most of the available light scattering studies on casein acidification have been restricted to transparent and therefore highly diluted samples, we now profit from a newly developed multiangle 3D light scattering instrument, which allows for time-resolved measurements in highly turbid samples. Our experiments clearly demonstrate the presence of two parallel pH-dependent processes, micellar reassembly and aggregation. Using a systematic investigation of the effect of casein concentration, acidification rate, and ionic strength, we are able to decouple these two processes and obtain detailed information about the pH-induced restructuration of the casein micelle structure that occurs prior to destabilization. Moreover, our experiments also unambiguously demonstrate that these micellar reassembly processes are highly concentration dependent, and that typical light scattering studies conducted under highly diluted conditions are resulting in findings that may not be relevant for the situation encountered in industrial processes at higher concentrations. Experiments conducted with covalently cross-linked micelles, where the pH-induced reassembly has been suppressed, further confirm our findings.

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Section: Methodsmentioning

confidence: 99%

The pH Induced Sol−Gel Transition in Skim Milk Revisited. A Detailed Study Using Time-Resolved Light and X-ray Scattering Experiments

et al. 2010

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“…Light scattering experiments are performed by using a 3D dynamic light scattering (3D-DLS) setup spectrometer (LS Instruments AG, Fribourg, Switzerland) [24][25][26][27]. The 3D scheme is based on the realization of two simultaneous scattering experiments performed at scattering vectors q with equal magnitude but different directions.…”

Section: B Experimental Techniquesmentioning

confidence: 99%

Impact of volume transition on the net charge of poly-N-isopropyl acrylamide microgels

et al. 2016

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We explore the electrostatic properties of poly-N-isopropyl acrylamide microgels in dilute, quasi-de-ionized dispersions and show that the apparent net charge of these thermosensitive microgels is an increasing function of their size, the size being conveniently varied by temperature. Our experimental results obtained in a combination of light scattering, conductivity, and mobility experiments are consistent with those obtained in Poisson-Boltzmann cell model calculations, effectively indicating that upon shrinking the number of counterions entrapped within the microgels increases. Remarkably, this behavior shows that the electrostatic energy per particle remains constant upon swelling or deswelling the microgel, resulting in a square root dependence of the net charge on the particle radius.

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“…In principle it is possible to reduce this path length to a few 100 lm by using a squared sample cell and measuring close to the edge. A so-called h À 2h scheme has been implemented previously using an additional sample goniometer to move the scattering cell accordingly in order to use this approach also for angles different from 90° [20]. However, by doing so it is only possible to measure at one particular angle at any given time and simultaneous multiangle measurements are not possible.…”

Section: Resultsmentioning

confidence: 99%

“…Here we therefore describe the development of a novel multiangle light-scattering instrument that implements the 3D cross-correlation scheme [14,17,[20][21][22] and allows for time-resolved measurements of SLS and DLS in turbid suspensions. We first describe the layout of the instrument and its calibration, and then demonstrate its superior performance with a study of the aggregation and sol-gel transition in acidified skim milk, where the high turbidity normally excludes the use of light scattering for a quantitative description of the aggregation kinetics.…”

Section: Introductionmentioning

confidence: 99%

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A new instrument for time-resolved static and dynamic light-scattering experiments in turbid media

Moitzi

Vavrin

Bhat

et al. 2009

Journal of Colloid and Interface Science

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We present a new 3D cross-correlation instrument that not only allows for static and dynamic scattering experiments with turbid samples but measures at four angles simultaneously. It thus extends the application of cross-correlation light scattering to time-resolved studies where we can, for example, efficiently investigate the temporal evolution of aggregating or phase separating turbid dispersions. The combination of multiangle 3D and on-line transmission measurements is an essential prerequisite for such studies. This not only provides time-resolved information about the overall size and shape of the particles through measurements of the mean apparent radius of gyration and hydrodynamic radius, but also on the weight-average apparent molar mass via the absolute forward scattering intensity. We present an efficient alignment strategy based on the novel design of the instrument and then the application range of the instrument using well-defined model latex suspensions. The effectiveness of the cross-correlation multiangle technique to monitor aggregation processes in turbid suspensions is finally shown for the acidification of skim milk during the yoghurt-making process. Due to the self-assembled nature of the casein micelles an understanding of the sol-gel process induced by the acidification is only feasible if time-resolved light-scattering experiments on an absolute scale are possible under industrially relevant conditions, where the casein solutions are highly turbid.

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Characterization of Turbid Colloidal Suspensions Using Light Scattering Techniques Combined with Cross-Correlation Methods

Cited by 208 publications

References 14 publications

The pH Induced Sol−Gel Transition in Skim Milk Revisited. A Detailed Study Using Time-Resolved Light and X-ray Scattering Experiments

The pH Induced Sol−Gel Transition in Skim Milk Revisited. A Detailed Study Using Time-Resolved Light and X-ray Scattering Experiments

Impact of volume transition on the net charge of poly-N-isopropyl acrylamide microgels

A new instrument for time-resolved static and dynamic light-scattering experiments in turbid media

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