The morphology and the microscopic internal dynamics of a bidimensional gel formed by spontaneous aggregation of gold nanoparticles confined at the water surface are investigated by a suite of techniques, including grazing-incidence x-ray photon correlation spectroscopy (GI-XPCS). The range of concentrations studied spans across the percolation transition for the formation of the gel. The dynamical features observed by GI-XPCS are interpreted in view of the results of microscopic imaging; an intrinsic link between the mechanical modulus and internal dynamics is demonstrated for all the concentrations. Our work presents an example of a transition from a stretched to a compressed correlation function actively controlled by quasistatically varying the relevant thermodynamic variable. Moreover, by applying a model proposed some time ago by Duri and Cipelletti [Europhys. Lett. 76, 972 (2006)] we are able to build a master curve for the shape parameter, whose scaling factor allows us to quantify a “long-time displacement length.” This characteristic length is shown to converge, as the concentration is increased, to the “short-time localization length” determined by pseudo-Debye-Waller analysis of the initial contrast. Finally, the intrinsic dynamics of the system is then compared with that induced by means of a delicate mechanical perturbation applied to the interface.
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Titolo: | Controlling the dynamics of a bidimensional gel above and below its percolation transition | |
Autori: | Orsi, D.; Ruta, B.; Chushkin, Y.; Pucci, A.; Ruggeri, G.; Baldi, Giacomo; Rimoldi, T.; Cristofolini, L. | |
Autori Unitn: | ||
Titolo del periodico: | PHYSICAL REVIEW E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS | |
Anno di pubblicazione: | 2014 | |
Numero e parte del fascicolo: | 4 | |
Codice identificativo Scopus: | 2-s2.0-84899731561 | |
Codice identificativo WOS: | WOS:000335795700003 | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1103/PhysRevE.89.042308 | |
Handle: | http://hdl.handle.net/11572/173688 | |
Appare nelle tipologie: | 03.1 Articolo su rivista (Journal article) |
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File | Descrizione | Tipologia | Licenza | |
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PhysRevE.89.042308.pdf | Versione editoriale (Publisher’s layout) | Tutti i diritti riservati (All rights reserved) | Open Access Visualizza/Apri |