Cross-linkable microgels are synthesized by copolymerization of NIPAM with 2-hydroxy-4-(methacryloyloxy)–benzophenone (HMABP) and are subsequently UV-cross-linked to obtain smart membranes exhibiting switchable resistance.
In
the present work, we study the shear-induced transformation
of polymer-rich lamellar phases into vesicles. The evolution of vesicle
size is studied by different scattering techniques, rheology, and
microscopy methods. The lamellar phase found in the system D2O/o-xylene/Pluronic PE9400/C8TAB can be fully transformed to multilamellar vesicles (MLVs)
by applying shear. The size of the MLVs is proportional to the inverse
square root of the shear rate. Hence, the polymer-based quaternary
system behaves similar to lamellar phases based on small surfactant
molecules. Additionally, we found a growth effect leading to a size
increase of the vesicles after shearing was stopped.
In our present work we confine fluorescent proteins and a fluorescent dye in structurally nearly identical bicontinuous microemulsions allowing to control confinement by systematically decreasing the water domain size. In this way the transition towards sub-diffusional transport is revealed.
We
study the complex mixture of a polyethylene oxide-b-polypropylene oxide-b-polyethylene oxide triblock
copolymer (Pluronic F127) with ionic liquid (IL) and Li-salt, which
is potentially interesting as an electrolyte system with decoupled
mechanical and ion-transport properties. Small-angle X-ray scattering
(SAXS) and differential scanning calorimetry (DSC) are employed to
scrutinize the phase structures and elucidate the ternary phase diagram.
These data are combined with the ion diffusivities obtained by pulsed
field gradient (PFG) nuclear magnetic resonance (NMR). Analyzing the
partial ternary phase diagram of F127/LiTFSI/Pyr14TFSI,
hexagonal, lamellar, and micellar mesophases are identified, including
two-phase coexistence regions. While the PPO block is immiscible with
the liquid, and forms the backbone of the mesostructured aggregates,
the PEO blocks are not well miscible with the IL. Poorly solvated,
the latter may still crystallize. At a higher IL content, PEO is further
solvated, but a major solvation effect occurs due to addition of Li-salt.
Li ions promote solubilization of the PEO chains in the IL, since
they coordinate to the PEO chains. This was identified as the mechanism
of a transition of the mesostructures, with increasing Li-salt content
changing from a hexagonal to a lamellar and further to a micellar
phase. In summary, both, the amount of IL and its compatibility with
the PEO block, the latter being controlled by the Li-salt amount,
influence the compositions of the formed mesophases and the ion diffusion
in their liquid regions.
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