Zwitterionic Amphiphilic Homopolymer Assemblies.

Zwitterionic amphiphilic homopolymers can be conveniently prepared in one-pot using activated ester-based polymer precursors. We show that these zwitterionic polymers can spontaneously self-assemble to form micelle-like and inverse micelle-like assemblies depending on the solvent environment; act as hydrophilic and hydrophobic nanocontainers in apolar and polar solvents respectively; undergo pH-responsive surface charge and size variations; exhibit least cytotoxicity compared to structurally analogous amphiphilic homopolymers.

Twisted vortex state.

We study a twisted vortex bundle where quantized vortices form helices circling around the axis of the bundle in a "force-free" configuration. Such a state is created by injecting vortices into a rotating vortex-free superfluid. Using continuum theory we determine the structure and the relaxation of the twisted state.

Vortex multiplication in applied flow: A precursor to superfluid turbulence.

A surface-mediated process is identified in 3He-B which generates vortices at a roughly constant rate. It precedes a faster form of turbulence where intervortex interactions dominate. This precursor becomes observable when vortex loops are introduced in low-velocity rotating flow at sufficiently low mutual friction dissipation at temperatures below 0.

An intrinsic velocity-independent criterion for superfluid turbulence.

Hydrodynamic flow in classical and quantum fluids can be either laminar or turbulent. Vorticity in turbulent flow is often modelled with vortex filaments. While this represents an idealization in classical fluids, vortices are topologically stable quantized objects in superfluids.