Yielding and flow of sheared colloidal glasses

@article{citeulike:2719840, abstract = {We have studied some of the rheological properties of suspensions of hard-sphere colloids with particular reference to behaviour near the concentration of the glass transition. First we monitored the strain on the samples during and after a transient step stress. We find that, at all values of applied step stress, colloidal glasses show a rapid, apparently elastic, recovery of strain after the stress is removed. This recovery is found even in samples which have flowed significantly during stressing. We attribute this behaviour to 'cage elasticity', the recovery of the stress-induced distorted environment of any particle to a more isotropic state when the stress is removed. Second, we monitored the stress as the strain rate \dot {\gamma } of flowing samples was slowly decreased. Suspensions which are glassy at rest show a stress which becomes independent of \dot {\gamma } as \dot {\gamma } \to 0 . This limiting stress can be interpreted as the yield stress of the glass and agrees well both with the yield stress deduced from the step stress and recovery measurements and that predicted by a recent mode coupling theory of sheared suspensions. Thus, the behaviours under steady shearing and transient step stress both support the idea that colloidal glasses have a finite yield stress. We note however that the samples do exhibit a slow accumulation of strain due to creep at stresses below the yield stress.}, author = {Petekidis, G. and Vlassopoulos, D. and Pusey, P. N. }, citeulike-article-id = {2719840}, doi = {10.1088/0953-8984/16/38/013}, journal = {Journal of Physics: Condensed Matter}, keywords = {colloids, edinburgh, glass, shear}, number = {38}, pages = {S3955--S3963}, posted-at = {2008-04-26 01:21:28}, priority = {2}, title = {Yielding and flow of sheared colloidal glasses}, url = {http://dx.doi.org/10.1088/0953-8984/16/38/013}, volume = {16}, year = {2004} }

TY - JOUR ID - citeulike:2719840 L3 - citeulike-article-id:2719840 TI - Yielding and flow of sheared colloidal glasses JF - Journal of Physics: Condensed Matter VL - 16 IS - 38 SP - S3955 EP - S3963 N2 - We have studied some of the rheological properties of suspensions of hard-sphere colloids with particular reference to behaviour near the concentration of the glass transition. First we monitored the strain on the samples during and after a transient step stress. We find that, at all values of applied step stress, colloidal glasses show a rapid, apparently elastic, recovery of strain after the stress is removed. This recovery is found even in samples which have flowed significantly during stressing. We attribute this behaviour to 'cage elasticity', the recovery of the stress-induced distorted environment of any particle to a more isotropic state when the stress is removed. Second, we monitored the stress as the strain rate \dot {\gamma } of flowing samples was slowly decreased. Suspensions which are glassy at rest show a stress which becomes independent of \dot {\gamma } as \dot {\gamma } \to 0 . This limiting stress can be interpreted as the yield stress of the glass and agrees well both with the yield stress deduced from the step stress and recovery measurements and that predicted by a recent mode coupling theory of sheared suspensions. Thus, the behaviours under steady shearing and transient step stress both support the idea that colloidal glasses have a finite yield stress. We note however that the samples do exhibit a slow accumulation of strain due to creep at stresses below the yield stress. KW - colloids KW - edinburgh KW - glass KW - shear AU - Petekidis, G AU - Vlassopoulos, D AU - Pusey, PN PY - 2004/// UR - http://dx.doi.org/10.1088/0953-8984/16/38/013 ER -