Dynamics of Concentrated Hard-Sphere Colloids Near a Wall
We investigate the Brownian motion of hard-sphere colloids near a solid wall by Evanescent Wave Dynamic Light Scattering (EWDLS). We carried out measurements for various volume fractions of sterically stabilized poly(methyl methacrylate) (PMMA) particles over a range of scattering wave vectors, q. While in the dilute regime, the near wall short-time diffusion is significantly slowed […]
Size Dependence in Hexagonal Mesoporous Germanium: Pore Wall Thickness versus Energy gap and Photoluminescence
A series of hexagonal mesoporous germanium semiconductors with tunable wall thickness is reported. These materials exhibit systematically blue shifted optical adsorption and strong room temperature photoluminescence properties that depend on the thickness of the framework wall, a behavior which is analogous to the blue shifted absorption in discrete nanocrystals. From: G.S. Armatas, M.G. Kanatzidis, “Size […]
Laser-Induced Cell Detachment and Patterning with Photodegradable Polymer Substrates
The photochemical degradation of poly(ketal)s and poly(acetal)s using fast laser sources was shown for the first time. The degradation was found to take place at very low energies, without the generation of free radical intermediates and led to low molecular weight by-products. The polymers (and their photoproducts) can be generally -egarded as safe (GRAS) materials […]
Bragg Polaritons: Strong Coupling and Amplification in an Unfolded Microcavity
Periodic incorporation of quantum wells inside a one-dimensional Bragg structure is shown to enhance coherent coupling of excitons to the electromagnetic Bloch waves. We demonstrate strong coupling of quantum well excitons to photonic crystal Bragg modes at the edge of the photonic band gap, which gives rise to mixed Bragg polariton eigenstates. The resulting Bragg […]
Probing Bioinspired Transport of Nanoparticles into Polymersomes
In biology the control of transmembrane transport is fundamental to functionality. The complexity of biological membranes and the diverse coupling of interactions, however, make direct investigations very difficult. Therefore the construction of synthetic artificial model membranes to study systematically their physical and chemical characteristics, and to find out how membrane functions can be modified and […]
Ordering Mechanisms in Epitaxial SiGe Nanoislands
We investigate and elucidate the surprising observation of atomically ordered domains in dome-shaped SiGe nanoislands. We show, through atomistic Monte Carlo simulations, that this ordering is a surface-related phenomenon, and that is driven by surface equilibrium rather than by surface kinetics. The ordering depends on facet orientation. The main source of ordering is the { […]
Light-Regulated Supramolecular Engineering of Polymeric Nanocapsules
The light-driven supramolecular engineering of water dispersable nanocapsules (NCPs) is reported. The novel method relies on the utilization of an appropriate phototrigger for the development or the disruption of the NCPs, in a controlled manner. The fabrication of dual-responsive polymeric vesicles is based on the formation of π-π H-type interactions between photosensistive moieties present within […]
Emerging Investigators 2012
A novel class of chemically addressable, multifunctional Giant Amphiphiles was synthesized in excellent yields and polydispersity following simultaneous or sequential living radical polymerization and the click, copper(I)-catalysed, azide alkyne cycloaddition (CuAAC). This new approach allows chemical tailoring of the protein polymer hybrids and in situ formation of nanocontainers and could be implemented in several biomedical […]
Sculpting oscillators with light within a nonlinear quantum fluid
Seeing macroscopic quantum states directly remains an elusive goal. Particles with boson symmetry can condense into quantum fluids, producing rich physical phenomena as well as proven potential for interferometric devices. However, direct imaging of such quantum states is only fleetingly possible in high-vacuum ultracold atomic condensates, and not in superconductors. Recent condensation of solid-state polariton […]
Hierarchical Formation of Supramolecular Transient Networks in Water: A Modular Injectable Delivery System
… Here we introduce a new concept of transient supra molecular networks where the macroscopic rheological and materials properties are tuned by controlled microscopic kinetics of the supramolecular interactions being responsible for the network formation. All of these properties will lead to the ideal material for protein delivery in regenerative medical applications. As proof-of-concept we […]