%0 Journal Article
%T Aging Dynamics of a Fractal Model Gel
%+ Laboratoire des colloïdes, verres et nanomatériaux (LCVN)
%A Suárez-Ledo, Miguel-Ángel
%A Kern, Norbert
%A Pitard, Estelle
%A Kob, Walter
%Z 30 pages, 25 figures
%< avec comité de lecture
%Z 09-017
%@ 0301-0104
%J Chemical Physics
%I Elsevier
%V Submitted
%P _
%8 2009
%D 2009
%Z 0812.3559
%Z Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
%Z Physics [physics]/Condensed Matter [cond-mat]/Disordered Systems and Neural Networks [cond-mat.dis-nn]Journal articles
%X Using molecular dynamics computer simulations we investigate the agingdynamics of a gel. We start from a fractal structure generated by the DLCA-DEFalgorithm, onto which we then impose an interaction potential consisting of ashort-range attraction as well as a long-range repulsion. After relaxing thesystem at T=0, we let it evolve at a fixed finite temperature. Depending on thetemperature T we find different scenarios for the aging behavior. For T>0.2 thefractal structure is unstable and breaks up into small clusters which relax toequilibrium. For T<0.2 the structure is stable and the dynamics slows down withincreasing waiting time. At intermediate and low T the mean squareddisplacement scales as t^{2/3} and we discuss several mechanisms for thisanomalous time dependence. For intermediate T, the self-intermediate scatteringfunction is given by a compressed exponential at small wave-vectors and by astretched exponential at large wave-vectors. In contrast, for low T it is astretched exponential for all wave-vectors. This behavior can be traced back toa subtle interplay between elastic rearrangements, fluctuations of chain-likefilaments, and heterogeneity.
%G English
%L hal-00364561
%U https://hal.science/hal-00364561
%~ CNRS
%~ UNIV-MONTP2
%~ LCVN
%~ UNIV-MONTPELLIER
%~ UM1-UM2