Hostname: page-component-cd9895bd7-jkksz Total loading time: 0 Render date: 2024-12-23T12:45:54.201Z Has data issue: false hasContentIssue false

Sequential Extraction of Late Exponentials (SELE): A technique for deconvolving multimodal correlation curves in Dynamic Light Scattering

Published online by Cambridge University Press:  10 March 2020

Preethi L Chandran*
Affiliation:
Department of Chemical Engineering, College of Engineering and Architecture, Howard University
*
Get access

Abstract:

In techniques such as Dynamic Light Scattering (DLS), Fluorescence Correlation Spectroscopy, and image mining, motion is tracked by the autocorrelation of a signal over logarithmic time scales. For instance the tracking signal in DLS is the scattered light intensity; it remains correlated at time scales where scant changes in the arrangement of the scattering particles occur, but decays exponentially at the time scales of their diffusion. When there are multiple time scales of motion (for instance due to scatterers of different sizes), the correlation curve has more than one exponential fall. Extracting the decay constants or hydrodynamic sizes due to each exponential fall in a multi-species field correlation curve becomes an ill-conditioned mathematical problem. We describe a new algorithm to invert a multi-modal correlation curve by Sequential Extraction of the Late Exponentials (SELE). The idea is that while the inversion of a multi-exponential equation may be ill posed, that of a single exponential is not. So we fit data windows towards to base of the correlation curve to extract the largest contribution species, remove the species contribution from the correlation curve, and repeat the process with the remnant curve. The single exponent can be robustly fitted by least-square minimization with initial guesses generated by an adapted cumutant technique (power-series) that includes stretch coefficients (measure of sample dispersity). The proposed algorithm resolves particle sizes separated by 3X, and is reliable against fluctuations in the correlation curve and to localized regions of suboptimal data. The algorithm can be used to track particle dynamics in solution in multi-species problems such as self-assembly.

Type
Articles
Copyright
Copyright © Materials Research Society 2020

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

References:

Pecora, R (2000) Dynamic light scattering measurement of nanometer particles in liquids. Journal of nanoparticle research 2(2):123-131.CrossRefGoogle Scholar
Pecora, R (2013) Dynamic light scattering: applications of photon correlation spectroscopy (Springer Science & Business Media).Google Scholar
Goldburg, WI (1999) Dynamic light scattering. American Journal of Physics 67(12):1152-1160.CrossRefGoogle Scholar
Schmitz, KS (1990) An Introduction to Dynamic Light Scattering by Macromolecules.Google Scholar
Dubois-Violette, E & De Gennes, PG (1967) Quasi-elastic scattering by dilute, ideal, polymer solutions: II. Effects of hydrodynamic interactions. Physics Physique Fizika 3(4):181.CrossRefGoogle Scholar
Horkay, F, Basser, PJ, Hecht, A-M, & Geissler, E (2008) Gel-like behavior in aggrecan assemblies J Chem Phys 128:135103-135107.CrossRefGoogle ScholarPubMed
Mailer, AG, Clegg, PS, & Pusey, PN (2015) Particle sizing by dynamic light scattering: non-linear cumulant analysis. Journal of Physics: Condensed Matter 27(14):145102.Google ScholarPubMed
Ostrowsky, N, Sornette, D, Parker, P, & Pike, ER (1981) Exponential sampling method for light scattering polydispersity analysis. Optica Acta: International Journal of Optics 28(8):1059-1070.CrossRefGoogle Scholar
Ju, RTC, Frank, CW, & Gast, AP (1992) CONTIN analysis of colloidal aggregates. Langmuir 8(9):2165-2171.CrossRefGoogle Scholar
Ross Hallett, F (1994) Particle size analysis by dynamic light scattering. Food Research International 27(2):195-198.CrossRefGoogle Scholar
Curtis, K, Millard, P, Basu, S, , F H, & Chandran, P (2016) Unusual Salt and pH effect of linear Polyethylenimine. PLoS ONE 11(9):e0158147.CrossRefGoogle Scholar
Basu, S, et al. (2018) Mannobiose‐Grafting Shifts PEI Charge and Biphasic Dependence on pH. Macromolecular Chemistry and Physics:1800423.Google Scholar
Frisken, BJ (2001) Revisiting the method of cumulants for the analysis of dynamic light-scattering data. Applied optics 40(24):4087-4091.CrossRefGoogle ScholarPubMed
Hassan, PA & Kulshreshtha, SK (2006) Modification to the cumulant analysis of polydispersity in quasielastic light scattering data. Journal of colloid and interface science 300(2):744-748.CrossRefGoogle ScholarPubMed
Franks, K, Kestens, V, Braun, A, Roebben, G, & Linsinger, TPJ (2019) Non-equivalence of different evaluation algorithms to derive mean particle size from dynamic light scattering data. Journal of Nanoparticle Research 21(9):195.CrossRefGoogle Scholar
Wei, L, Yajing, W, & Jin, S (2013) Optimal fitting cumulants method for dynamic light scattering. Acta Optica Sinica 33(12):1229001.Google Scholar
Roger, V, Cottet, H, & Cipelletti, L (2016) A new robust estimator of polydispersity from dynamic light scattering data. Analytical chemistry 88(5):2630-2636.CrossRefGoogle ScholarPubMed
Scotti, A, et al. (2015) The CONTIN algorithm and its application to determine the size distribution of microgel suspensions. The Journal of chemical physics 142(23):234905.CrossRefGoogle ScholarPubMed