2 research outputs found
Temporally Anticorrelated Motion of Nanoparticles at a Liquid Interface
Quantum dots at the hexane–glycerol
interface exhibited
unexpected behavior including highly dynamic adsorption/desorption,
where the lateral nanoparticle motion was anomalously fast immediately
after adsorption and prior to desorption. At the interface, particles
exhibited pseudo-Brownian lateral motion, in which the instantaneous
diffusion coefficient was temporally anticorrelated, in agreement
with our simulations involving fractional Brownian motion in the surface-normal
direction. These phenomena suggest that, in contrast to the conventional
picture for colloidal particles, nanoparticles explore a landscape
of metastable interfacial positions, with different exposures to the
two adjacent phases
Scaling Behavior and Segment Concentration Profile of Densely Grafted Polymer Brushes Swollen in Vapor
The
scaling of the thickness, <i>h</i><sub>s</sub>, of
a densely grafted polymer brush of chain length <i>N</i> and grafting density σ swollen in vapor agrees quantitatively
with the scaling reported by Kuhl et al. for densely grafted brushes
swollen in liquid. Deep in the brush, next to the substrate, the shape
of the segment concentration profile is the same whether the brush
is swollen by liquid or by vapor. Differences in the segment concentration
profile are manifested primarily in the swollen brush interface with
the surrounding fluid. The interface of the polymer brush swollen
in vapor is much more abrupt than that of the same brush swollen in
liquid. This has implications for the compressibility of the swollen
brush surface and for fluctuations at that surface