Speaker
Dr
Urs Gasser Gasser
(Laboratory for Neutron Scattering, Paul Scherrer Institut)
Description
We present a small angle X-ray scattering study of crystals formed by temperature-sensitive, swollen microgel particles consisting of poly(N-isopropylacrylamide) co-polymerized with acrylic acid and 5 mol% of cross-linker. As for hard spheres, the random hexagonal close packed structure is predominant during crystal growth and slowly transforms towards the face-centered cubic structure. However, a transient phase of body-centered cubic crystal is observed in an intermediate range of effective volume fractions. We estimate that the studied suspensions are close to a transition from fcc to bcc structure that can be understood by the tendency of the system to maximize excluded volume and minimize the contact area between the particles.
Primary author
Dr
Urs Gasser Gasser
(Laboratory for Neutron Scattering, Paul Scherrer Institut)
Co-authors
Prof.
Alberto Fernandez-Nieves
(Georgia Institute of Technology)
Mr
Andrea Scotti
(Paul Scherrer Institut)
Andreas Menzel
(Paul Scherrer Institut)
Dr
Juan-Jose Lietor-Santos
(Georgia Institute of Technology)
Dr
Oliver Bunk
(Paul Scherrer Institut)
