Colloidal System To Explore Structural and Dynamical Transitions in Rod Networks, Gels, and Glasses Export

@article{citeulike:5739716, abstract = {PMID: 19572513 We introduce a model system consisting of self-assembled polyamide anisotropic colloids suspended in an aqueous surfactant solution for studies of the dynamics of rod networks, gels, and glasses. The colloidal particles are formed by recrystallization of a polyamide from an aqueous surfactant phase at temperatures from 59 to 100 °C. The aspect ratio increases monotonically with temperature from T = 59 °C to T = 100 °C and rods with an aspect ratio r = 8 ± 1 to r = 306 ± 14 form. We show by confocal laser scanning microscopy and dynamic light scattering a structural transition from dilute rod behavior with diffusive dynamics to a homogeneous network structure with increasingly slow dynamics as the volume fraction is increased. Furthermore, increasing the aspect ratio of rods induces a similar structural transition from dilute rod behavior to a network structure, although at a lower volume fraction. Finally, we vary the pair potential between the rods by a polymer-induced depletion interaction and thereby observe an unexpected network-to-bundle transition. The bundles are several rod diameters wide and 1−2 rod lengths long. The rods appear to be ordered nematically within each bundle. The bundling transition leads to an order of magnitude decrease in the storage modulus of the suspensions. The results can be applied to develop strategies for complex fluid stabilization as well as for fundamental studies of rod gelation and vitrification.}, author = {Wilkins, Georgina M. H. and Spicer, Patrick T. and Solomon, Michael J.}, citeulike-article-id = {5739716}, citeulike-linkout-0 = {http://dx.doi.org/10.1021/la9004196}, citeulike-linkout-1 = {http://pubs.acs.org/doi/abs/10.1021/la9004196}, day = {18}, doi = {10.1021/la9004196}, journal = {Langmuir}, keywords = {colloidal, experiments, glasses, on}, month = {August}, number = {16}, pages = {8951--8959}, posted-at = {2009-09-08 12:53:02}, priority = {3}, title = {Colloidal System To Explore Structural and Dynamical Transitions in Rod Networks, Gels, and Glasses}, url = {http://dx.doi.org/10.1021/la9004196}, volume = {25}, year = {2009} }

TY - JOUR ID - citeulike:5739716 L3 - citeulike-article-id:5739716 N2 - PMID: 19572513 We introduce a model system consisting of self-assembled polyamide anisotropic colloids suspended in an aqueous surfactant solution for studies of the dynamics of rod networks, gels, and glasses. The colloidal particles are formed by recrystallization of a polyamide from an aqueous surfactant phase at temperatures from 59 to 100 °C. The aspect ratio increases monotonically with temperature from T = 59 °C to T = 100 °C and rods with an aspect ratio r = 8 ± 1 to r = 306 ± 14 form. We show by confocal laser scanning microscopy and dynamic light scattering a structural transition from dilute rod behavior with diffusive dynamics to a homogeneous network structure with increasingly slow dynamics as the volume fraction is increased. Furthermore, increasing the aspect ratio of rods induces a similar structural transition from dilute rod behavior to a network structure, although at a lower volume fraction. Finally, we vary the pair potential between the rods by a polymer-induced depletion interaction and thereby observe an unexpected network-to-bundle transition. The bundles are several rod diameters wide and 1−2 rod lengths long. The rods appear to be ordered nematically within each bundle. The bundling transition leads to an order of magnitude decrease in the storage modulus of the suspensions. The results can be applied to develop strategies for complex fluid stabilization as well as for fundamental studies of rod gelation and vitrification. IS - 16 JF - Langmuir EP - 8959 TI - Colloidal System To Explore Structural and Dynamical Transitions in Rod Networks, Gels, and Glasses VL - 25 SP - 8951 KW - colloidal KW - experiments KW - glasses KW - on AU - Wilkins, Georgina AU - Spicer, Patrick AU - Solomon, Michael PY - 2009/08/18/ UR - http://dx.doi.org/10.1021/la9004196 ER -