Light scattering studies on a coagulating polystyrene latex

Lips, Alex; Smart, C.; Willis, E.

doi:10.1039/tf9716702979

Cited by 102 publications

(34 citation statements)

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“…Old determinations of k~ for gold and selenium hydrosols (la, 2) give values that are much higher, even higher than the yon Smoluchowski value. Our turbidimetric results (46-56% of the yon Smoluchowski value) are in good agreement with recent lightscattering work of Lips, Smart, and Willis on polystyrene latex in water (6), who have found a rate constant of 67-69% of the yon Smoluchowski value, and with recent low-angle light-scattering data of Lips and Willis (7), who have found 48-62% of the yon Smoluchowski value.…”

Section: Discussionsupporting

confidence: 81%

“…The rate of rapid coagulation of lyophobic colloids has been measured in the past fifty years with various methods, such as direct counting in the ultramicroscope (la, 2, 3) or in the Coulter Counter (4,5), light scattering (6,7), and turbidimetry (2,8). During coagulation many processes occur; they can be described in general as the combination of an aggregate of m monomers with an aggregate of n monomers to form one of m + r~ monomers.…”

Section: Introductionmentioning

confidence: 99%

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Rapid coagulation of polystyrene latex in a stopped-flow spectrophotometer

Lichtenbelt

Pathmamanoharan

Wiersema

1974

Journal of Colloid and Interface Science

102

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With a stopped-flow method the rapid coagulation by electrolyte of several polystyrene latices is measured. By extrapolating back to zero time the initial process of two single particles forming a doublet is observed. We find an average rate constant kn = 6.0 ;< l0 -12 p-1 cm a sec-1 at 20°C, where p is the number of particles; this constant is lowered to 4.9 ;< 10 -1~ p-1 cm a sec -1 when we assume that the particle diameters are 5% lower than the Dow values. These values are equal to 56 and 46%, respectively, of the yon Smoluehowski values. Using the theory of hydrodynamic interaction, this gives Hamaker constants A = 7.0 X 10 -21 J or 1.5 X 10 -21 J, respectively, in good agreement with theoretical predictions.

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Section: Discussionsupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Rapid coagulation of polystyrene latex in a stopped-flow spectrophotometer

Lichtenbelt

Pathmamanoharan

Wiersema

1974

Journal of Colloid and Interface Science

102

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“…The procedure reported in Ref. [26] allows obtaining the value of W from the initial slope of the turbidity as a function of time [26,28,27,29]. This methodology is very convenient since it only requires the use of a spectrophotometer.…”

Section: Flocculation Of Solid Particlesmentioning

confidence: 99%

“…Lips et al [26], and also Lichtenbelt et al [27] developed experimental methodologies suitable for quantifying the rate of doublet formation (k 11 ) with light scattering. The procedure reported in Ref.…”

Section: Flocculation Of Solid Particlesmentioning

confidence: 99%

Nanoemulsion stability: Experimental evaluation of the flocculation rate from turbidity measurements

Rahn-Chique¹,

Puertas²,

Romero-Cano³

et al. 2012

Advances in Colloid and Interface Science

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The coalescence of liquid drops induces a higher level of complexity compared to the classical studies about the aggregation of solid spheres. Yet, it is commonly believed that most findings on solid dispersions are directly applicable to liquid mixtures. Here, the state of the art in the evaluation of the flocculation rate of these two systems is reviewed. Special emphasis is made on the differences between suspensions and emulsions. In the case of suspensions, the stability ratio is commonly evaluated from the initial slope of the absorbance as a function of time under diffusive and reactive conditions. Puertas and de las Nieves (1997) developed a theoretical approach that allows the determination of the flocculation rate from the variation of the turbidity of a sample as a function of time. Here, suitable modifications of the experimental procedure and the referred theoretical approach are implemented in order to calculate the values of the stability ratio and the flocculation rate corresponding to a dodecane-in-water nanoemulsion stabilized with sodium dodecyl sulfate. Four analytical expressions of the turbidity are tested, basically differing in the optical cross section of the aggregates formed. The first two models consider the processes of: a) aggregation (as described by Smoluchowski) and b) the instantaneous coalescence upon flocculation. The other two models account for the simultaneous occurrence of flocculation and coalescence. The latter reproduce the temporal variation of the turbidity in all cases studied (380 ≤ [NaCl] ≤ 600 mM), providing a method of appraisal of the flocculation rate in nanoemulsions.

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“…Absolute CRCs are usually needed for comparing the theoretical predictions of aggregation kinetics with the experimental results, or for deriving information on interactions between particles. [2][3][4][5] In many applications, on the other hand, the relative coagulation rates are sufficient.…”

Section: Introductionmentioning

confidence: 99%

Progress in coagulation rate measurements of colloidal dispersions

Sun

2011

Soft Matter

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This article reviews recent advances in coagulation rate measurements of colloidal dispersions, with emphasis on the turbidity method. For turbidity method, measurement of the coagulation rate relies upon the turbidity change resulting from the coagulation process, and the measuring sensitivity significantly depends on particle size and the wavelength used. There exists a ''zero sensitivity'' blind point for measurement at a specific wavelength, suggesting that such measurements should be performed at a wavelength some distance from the blind point. The major difficulty in determining absolute coagulation rate constant (CRC) by light scattering and turbidity measurements is how to theoretically solve the scattering problem of 2-particle aggregates. The T-matrix method accurately solves this problem, showing its superiority over various earlier theoretical approximations (applicable only to small particles). Results from studies on effects of forward scattering, multiple scattering, etc., provide guidelines for choosing proper particle size and volume fraction for the allowed margin of measurement error. Most of these findings on turbidity methods are also valid or applicable to other scattering methods. Finally, we introduce a new microscopic approach to assess the colloidal stability at individual particle levels, by means of directly observing artificially induced collision with the aid of optical tweezers.

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Light scattering studies on a coagulating polystyrene latex

Cited by 102 publications

References 0 publications

Rapid coagulation of polystyrene latex in a stopped-flow spectrophotometer

Rapid coagulation of polystyrene latex in a stopped-flow spectrophotometer

Nanoemulsion stability: Experimental evaluation of the flocculation rate from turbidity measurements

Progress in coagulation rate measurements of colloidal dispersions

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