title: Morphology and mobility of synthetic colloidal aggregates.
abstract: The relationship between geometric and dynamic properties of fractal-like aggregates is studied in the continuum mass and momentum-transfer regimes. The synthetic aggregates were generated by a cluster-cluster aggregation algorithm. The analysis of their morphological features suggests that the fractal dimension is a descriptor of a cluster's large-scale structure, whereas the fractal prefactor is a local-structure indicator. For a constant fractal dimension, the prefactor becomes also an indicator of a cluster's shape anisotropy. The hydrodynamic radius of orientationally averaged aggregates was calculated via molecule-aggregate collision rates determined from the solution of a Laplace equation. An empirical expression that relates the aggregate hydrodynamic radius to its radius of gyration and the number of primary particles is proposed. The suggested expression depends only on geometrical quantities, being independent of statistical (ensemble-averaged) properties like the fractal dimension and prefactor. Hydrodynamic radius predictions for a variety of fractal-like aggregates are in very good agreement with predictions of other methods and literature values. Aggregate dynamic shape factors and DLCA individual monomer hydrodynamic shielding factors are also calculated.
authors.affiliation: European Commission, Joint Research Centre, I-21027 Ispra, VA, Italy; Department of Chemical Engineering, Aristotle University, GR-54124 Thessaloniki, Greece. Electronic address: admelas@auth.gr.
authors.forename: Anastasios D
authors.initials: AD
authors.lastname: Melas
authors.affiliation: European Commission, DG Energy, L-2530 Luxembourg, Luxembourg.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Isella
authors.affiliation: Department of Chemical Engineering, Aristotle University, GR-54124 Thessaloniki, Greece; Aerosol & Particle Technology Laboratory, CERTH/CPERI, P.O. Box 60361, GR-57001 Thessaloniki, Greece.
authors.forename: Athanasios G
authors.initials: AG
authors.lastname: Konstandopoulos
authors.affiliation: European Commission, Joint Research Centre, I-21027 Ispra, VA, Italy.
authors.forename: Yannis
authors.initials: Y
authors.lastname: Drossinos
keywords: Fractal dimension; Fractal prefactor; Hydrodynamic radius; Power-law aggregates; Radius of gyration; Shape anisotropy