Conveners
Soft Matter Canada 2017 / Matière molle Canada 2017
- Barbara Frisken (Simon Fraser University)
- Anand Yethiraj (Memorial University of Newfoundland)
Description
A satellite meeting to the CAP Congress that will consist of a full day of events including talks and networking time, with a focus on supporting the network of Canadian physicists working in soft matter, which includes people working with polymers, colloids, and bio-inspired systems.
Many polymers exhibit structural heterogeneity on the nanoscale, either by partially crystallizing or, in the case of copolymers, by phase separation. Their mechanical properties are controlled by molecular level mechanisms at interfaces between crystalline-amorphous or rubbery-glassy regions, respectively. In this talk, we employ multiscale molecular dynamics simulations to investigate...
Polymers subject to confinement in a narrow channel tend to be linearly ordered along the axis of the channel. When such a confined polymer is in a folded state, the internal overlap leads to a reduction in conformational entropy that increases the free energy. A similar effect arises when two different polymers overlap along the channel. In each case, the free energy tends to increase with...
The equivalent behavior among analogous block copolymer systems involving chemically distinct molecules or mathematically different models has long hinted at an underlying universality, but only recently has it been rigorously demonstrated by matching results from different simulations. The profound implication of universality is that simple coarse-grained models can be calibrated so as to...
Block copolymers, which are composed of two or more chemically distinct sub-chains or blocks, could self-assembled to form various ordered phases. Among the block copolymer phases, the spherical packing phases are of particular interest because it resembles the familiar atomic crystals. For a very long time, it had been believed that the stable spherical phases of diblock copolymers are mainly...
The polymerisation index, N, is the most important parameter describing a particular polymer. Properties such as the glass transition temperature, solubility, and phase behaviour depend strongly on N. In most cases, the small N region describes the transition between oligomer and polymer, where the change in physical parameters is most pronounced. The most monodisperse polymers widely...
Students and Postdocs will have an opportunity to introduce themselves to the community and summarize their project.
In this talk we first introduce a new extension to the structural phase field crystal (XPFC) approach that employs rotationally invariant multi-point correlation functions which allow for a progression of complex materials phenomena to be simulated, ranging from pressure-induced phase transitions between vapor-liquid-solid phases to polycrystalline solidification and grain growth in both...
Block copolymers that form thermoplastic elastomers have some blocks that form glassy domains and other elastic blocks that bind the glassy domains together, leading to strong, and yet elastic materials. Binding glassy domains requires molecular bridges between domains, with the greatest number of molecules bridging between domains being the most desirable. Starblock copolymers have several...
The Sanchez-Lacombe equation of state, despite an inherent thermodynamic inconsistency, can be shown to be consistent, predictive and quantitative for numerical solubility calculations. The theory can thus be shown to be one of the simplest and most versatile equations of state with a predictive capacity which, in a sense, has no free parameters. Diverse solubility phenomena such as blowing...
Collagen is the fundamental structural protein in vertebrates and is widely used as biomaterial, for example as a substrate for tissue engineering. Assembled from individual triple-helical proteins to make strong fibres, collagen is a beautiful example of a hierarchical self-assembling system. Using a combination of biophysical and biochemical techniques, we are investigating how its...
We study the effects of binding kinetics on the diffusive transport of particles within narrow channels, which exhibit single-file diffusion (SFD). We computationally study the binding of particles to the channel wall, leading to transient immobility. We find rapid binding kinetics leads to the canonical result that diffusive transport is unchanged by SFD, while slow binding kinetics leads...
Our goal is to uncover mechanisms for macromolecular transport in the crowded environment of living cells. We use a nanoscale (experimental) model polymer-colloid system to examine the interplay between excluded volume and charge in macromolecular crowding. In this system, we measure polymer structure by small-angle neutron scattering (SANS) and polymer and crowder dynamics by...
Sensitive visualization and conformational control of biopolymer interactions at super-molecular (tens to hundreds of nanometers) dimensions is important because it is at these scales that biopolymers undergo liquid-liquid phase separation. In particular, it remains unclear how protein-protein interactions regulate the formation of non-membranous organelles, with specific functions inside the...
We have investigated the start-up flow and yielding transition of Carbopol 940 in a vertical pipe. Carbopol is a soft solid when the applied shear stress is lower than its yield stress, but flows for higher stresses. Carbopol in a vertical pipe was displaced by an immiscible Newtonian fluid injected at a constant rate at the bottom of the pipe. Measurements of the wall shear stress and the...
Nature offers amazing examples of nanostructured molecules and materials. I will focus on phytoglycogen, a highly branched polymer of glucose produced in the form of dense, monodisperse nanoparticles by some varieties of plants such as sweet corn. The particles are chemically simple, but have a special dendrimeric or tree-like structure that produces interesting and unusual properties such as...
This talk discusses x-ray photon correlation spectroscopy under shear (Rheo-XPCS) as a method for studying the behaviour of soft nanostructured materials in response to applied deformation. In XPCS, the characteristic “speckle” patterns resulting from the scattering of coherent x-rays are auto-correlated to uncover collective dynamics in a sample. XPCS can currently be used to study the...
Soft colloidal particles have inspired fundamental and practical interest recently for their rich and tunable properties, both on the single-particle level and collectively in bulk suspensions. Interdisciplinary research has led to applications in the chemical, biomedical, food, consumer care, and pharmaceutical industries. The simplest example of a soft colloid may be a linear polymer coil,...
