Description: Kinetic arrest of crowded soft spheres in solvents of varying quality

This title appears in the Scientific Report : 2002

Kinetic arrest of crowded soft spheres in solvents of varying quality

Crowded solutions of multiarm star polymers, representing model colloidal spheres with ultrasoft repulsive interactions, undergo a reversible gelation transition upon heating in solvents of intermediate quality (between good and Theta). This unusual phenomenon is due to the kinetic arrest of the swo...

Personal Name(s):	Stiakakis, E.
	Vlassopulos, D. / Loppinet, B. / Roovers, J. / Meier, G.
Contributing Institute:	Weiche Materie; IFF-WM
Published in:	Physical review / E, 66 (2002) S. 0518041 - 0518049
Imprint:	College Park, Md. APS 2002
Physical Description:	0518041 - 0518049
DOI:	10.1103/PhysRevE.66.051804
Document Type:	Journal Article
Research Program:	Kondensierte Materie
Series Title:	Physical Review E 66
Subject (ZB):	J
Link:	OpenAccess
	Publikationsportal JuSER

Please use the identifier: http://dx.doi.org/10.1103/PhysRevE.66.051804 in citations.
Please use the identifier: http://hdl.handle.net/2128/1600 in citations.

Crowded solutions of multiarm star polymers, representing model colloidal spheres with ultrasoft repulsive interactions, undergo a reversible gelation transition upon heating in solvents of intermediate quality (between good and Theta). This unusual phenomenon is due to the kinetic arrest of the swollen interpenetrating spheres at high temperatures, forming clusters, in analogy to the colloidal glass transition. In this work we demonstrate that the choice of the solvent has a dramatic effect on the gelation transition, because of the different degree of star swelling (at the same temperature) associated with the solvent quality. We construct a generic kinetic phase diagram for the gelation of different stars in different solvents (gelation temperature against effective volume fraction, phi) and propose a critical "soft sphere close packing" volume fraction phi(c) distinguishing the temperature-induced (for phi<phi(c)) from the concentration-induced (for phi>phi(c)) glass-like gelation. We conclude that appropriate selection of the solvent allows for manipulation of the sol-gel transition in such ultrasoft colloids.