Microstructure of equilibrium fluid clusters in colloid-polymer suspensions

@article{citeulike:2883881, abstract = {Several studies on colloidal depletion systems have reported the existence of a fluid phase consisting of clusters of particles above a critical polymer concentration that acts as a precursor regime to the gel phase at low colloid volume fractions (0.20). The clusters are found to be stable against further aggregation suggesting that individual particles are localized within a cluster. However the clusters themselves behave as distinct entities in an equilibrium fluid phase. In this study, we probe the internal microstructure of the cluster entities by ultrasmall angle x-ray scattering (USAXS) techniques. These studies reveal that over the accessible length scales, the microstructure of the particle clusters are similar to that observed in dense space-spanning depletion gels. The origin of these clusters is unclear but the scattering patterns as they settle with time reveal that the percolation of the clusters to form space-spanning gels does not influence their internal microstructure. These observations lend support to the hypothesis that the formation of space-spanning depletion gels at a given volume fraction is driven by the percolation of the particle clusters. Settling experiments at =0.08 also provide rough estimates of the cluster sizes that appear consistent with the observations from the USAXS experiments.}, author = {Gopalakrishnan, V. and Zukoski, C. F. }, citeulike-article-id = {2883881}, doi = {http://dx.doi.org/10.1103/PhysRevE.75.021406}, journal = {Physical Review E (Statistical, Nonlinear, and Soft Matter Physics)}, keywords = {2007, gel, pre}, number = {2}, posted-at = {2008-06-11 22:45:41}, priority = {2}, publisher = {APS}, title = {Microstructure of equilibrium fluid clusters in colloid-polymer suspensions}, url = {http://dx.doi.org/10.1103/PhysRevE.75.021406}, volume = {75}, year = {2007} }

TY - JOUR ID - citeulike:2883881 L3 - citeulike-article-id:2883881 TI - Microstructure of equilibrium fluid clusters in colloid-polymer suspensions JF - Physical Review E (Statistical, Nonlinear, and Soft Matter Physics) VL - 75 IS - 2 PB - APS N2 - Several studies on colloidal depletion systems have reported the existence of a fluid phase consisting of clusters of particles above a critical polymer concentration that acts as a precursor regime to the gel phase at low colloid volume fractions (0.20). The clusters are found to be stable against further aggregation suggesting that individual particles are localized within a cluster. However the clusters themselves behave as distinct entities in an equilibrium fluid phase. In this study, we probe the internal microstructure of the cluster entities by ultrasmall angle x-ray scattering (USAXS) techniques. These studies reveal that over the accessible length scales, the microstructure of the particle clusters are similar to that observed in dense space-spanning depletion gels. The origin of these clusters is unclear but the scattering patterns as they settle with time reveal that the percolation of the clusters to form space-spanning gels does not influence their internal microstructure. These observations lend support to the hypothesis that the formation of space-spanning depletion gels at a given volume fraction is driven by the percolation of the particle clusters. Settling experiments at =0.08 also provide rough estimates of the cluster sizes that appear consistent with the observations from the USAXS experiments. KW - 2007 KW - gel KW - pre AU - Gopalakrishnan, V AU - Zukoski, CF PY - 2007/// UR - http://dx.doi.org/10.1103/PhysRevE.75.021406 ER -