Elasticity and clustering in concentrated depletion gels.
X-ray scattering and rheology are employed to study the volume fraction dependence of the collective structure and elastic moduli of concentrated nanoparticle-polymer depletion gels. The nonequilibrium gel structure consists of locally densified nonfractal clusters and narrow random interfaces. The elastic moduli display a power law dependence on volume fraction with effective exponents that decrease with increasing depletion attraction strength. A microscopic theory that combines local structural information with a dynamic treatment of gelation is in good agreement with the observations.
Ramakrishnan
S
S
Department of Chemical and Biomolecular Engineering , University of Illinois, Urbana, Illinois 61801, USA.
Chen
Y-L
YL
Schweizer
K S
KS
Zukoski
C F
CF
D003102:Colloids / Q000032:analysis / Q000737:chemistry*; D003198:Computer Simulation; D004548:Elasticity; D020100:Hydrogels / Q000032:analysis / Q000737:chemistry*; D008956:Models, Chemical; D043942:Nanotubes / Q000032:analysis / Q000737:chemistry*; D044367:Phase Transition; D011108:Polymers / Q000032:analysis / Q000737:chemistry*; D012996:Solutions; D014783:Viscosity
D003102:Colloids; D020100:Hydrogels; D011108:Polymers; D012996:Solutions