Direct observation of a local structural mechanism for dynamic arrest

@article{citeulike:2937461, abstract = {The mechanism by which a liquid may become arrested, forming a glass or gel, is a long-standing problem of materials science. In particular, long-lived (energetically) locally favoured structures (LFSs), the geometry of which may prevent the system relaxing to its equilibrium state, have long been thought to play a key role in dynamical arrest. Here, we propose a definition of LFSs which we identify with a novel topological method and directly measure with experiments on a colloidal liquid–gel transition. The population of LFSs is a strong function of (effective) temperature in the ergodic liquid phase, rising sharply approaching dynamical arrest, and indeed forms a percolating network that becomes the 'arms' of the gel. Owing to the LFSs, the gel is unable to reach equilibrium, crystal–gas coexistence. Our results provide direct experimental observation of a link between local structure and dynamical arrest, and open a new perspective on a wide range of metastable materials.}, author = {Patrick and Williams, Stephen R. and Ohtsuka, Takehiro and Tanaka, Hajime }, citeulike-article-id = {2937461}, doi = {http://dx.doi.org/10.1038/nmat2219}, journal = {Nat Mater}, keywords = {colloidal-gel, confocal, journal-club, structure}, month = {July}, number = {7}, pages = {556--561}, posted-at = {2008-06-27 15:28:58}, priority = {0}, publisher = {Nature Publishing Group}, title = {Direct observation of a local structural mechanism for dynamic arrest}, url = {http://dx.doi.org/10.1038/nmat2219}, volume = {7}, year = {2008} }

TY - JOUR ID - citeulike:2937461 L3 - citeulike-article-id:2937461 TI - Direct observation of a local structural mechanism for dynamic arrest JF - Nat Mater VL - 7 IS - 7 SP - 556 EP - 561 PB - Nature Publishing Group N2 - The mechanism by which a liquid may become arrested, forming a glass or gel, is a long-standing problem of materials science. In particular, long-lived (energetically) locally favoured structures (LFSs), the geometry of which may prevent the system relaxing to its equilibrium state, have long been thought to play a key role in dynamical arrest. Here, we propose a definition of LFSs which we identify with a novel topological method and directly measure with experiments on a colloidal liquid–gel transition. The population of LFSs is a strong function of (effective) temperature in the ergodic liquid phase, rising sharply approaching dynamical arrest, and indeed forms a percolating network that becomes the 'arms' of the gel. Owing to the LFSs, the gel is unable to reach equilibrium, crystal–gas coexistence. Our results provide direct experimental observation of a link between local structure and dynamical arrest, and open a new perspective on a wide range of metastable materials. KW - colloidal-gel KW - confocal KW - journal-club KW - structure AU - Patrick AU - Williams, Stephen AU - Ohtsuka, Takehiro AU - Tanaka, Hajime PY - 2008/07// UR - http://dx.doi.org/10.1038/nmat2219 ER -