2018 Impact factor 1.686
Soft Matter and Biological Physics

Eur. Phys. J. E 2, 359-365

Viscosity critical behaviour at the gel point in a 3d lattice model

E. Del Gado1 - L. de Arcangelis2 - A. Coniglio1

1 Dipartimento di Scienze Fisiche, Università di Napoli "Federico II'', INFM Sezione di Napoli, Mostra d'Oltremare pad. 19, 80125 Napoli, Italy
2 Dipartimento di Ingegneria dell'Informazione, Seconda Università di Napoli, INFM Sezione di Napoli, via Roma 29, 81031 Aversa (Caserta), Italy
antonio.coniglio@na.infn.it

Received 20 December 1999 and Received in final form 18 February 2000

Abstract
Within a recently introduced model based on the bond-fluctuation dynamics, we study the viscoelastic behaviour of a polymer solution at the gelation threshold. We here present the results of the numerical simulation of the model on a cubic lattice: the percolation transition, the diffusion properties and the time autocorrelation functions have been studied. From both the diffusion coefficients and the relaxation times critical behaviour a critical exponent k for the viscosity coefficient has been extracted: the two results are comparable within the errors giving $k\sim 1.3$, in close agreement with the Rouse model prediction and with some experimental results. In the critical region below the transition threshold the time autocorrelation functions show a long-time tail which is well fitted by a stretched exponential decay.

PACS
05.20.-y Classical statistical mechanics - 82.70.Gg gels and sols - 83.10.Nn Polymer dynamics

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