Interfacial rheology of linearly growing polyelectrolyte multilayers at the water-air interface: from liquid to solid viscoelasticity.

Despite the long history of investigations of polyelectrolyte multilayer formation on solid or liquid surfaces, important questions remain open concerning the construction of the first set of layers. These are generally deposited on a first anchoring layer of different chemistry, influencing their construction and properties. We propose here an in-depth investigation of the formation of NaPSS/PAH multilayers at the air/water interface in the absence of a chemically different anchoring layer, profiting from the surface activity of NaPSS.

PEG-in-PDMS drops stabilised by soft silicone skins as a model system for elastocapillary emulsions with explicit morphology control.

Hypothesis: The morphology of ordinary macro-emulsions is controlled by their high interfacial energies, i.e., by capillarity, leading to well-known structural features which can be tuned only over a narrow range.

Fast and efficient shear-force assisted production of covalently functionalized oxide nanosheets.

Hypothesis: While controlled and efficient exfoliation of layered oxides often remains a time consuming challenge, the surface modification of inorganic nanosheets is of outmost importance for future applications. The functionalization of the bulk material prior to exfoliation should allow the application of tools developped for Van der Waals materials to directly produce functionalized oxide nanosheets.

Experiments: The Aurivillius phase BiSrTaO is functionalized by a linear aliphatic phosphonic acid via microwave-assisted reactions.

Towards a rational morphology control of frozen copolymer aggregates.

Kinetically frozen copolymer micelles are commonly prepared by confining amphiphilic block copolymers in the evaporating dispersed phase of oil-in-water emulsions. We revisit the mechanisms of this process by examining its successive steps separately: the formation of the solvent/water interface, the emulsification, the solvent evaporation and the formation of aggregates. We bring into evidence that: (i) spontaneous water-in-solvent emulsification, i.

Intravenous and intratumoral injection of Pluronic P94: The effect of administration route on biodistribution and tumor retention.

Pluronics P94 are block-copolymer showing prolonged circulation time and tumor-cell internalization in vitro, suggesting a potential for tumor accumulation and as a drug carrier. Here we report the results of the radiolabeled-P94 unimers (P94-In-DTPA) on tumor uptake/retention and biodistribution after intravenous and intratumoral injection to tumor-bearing mice. Intravenous administration results in a high radioactive signal in the liver; while in tumor and other healthy tissues only low levels of radioactivity could be measured.

A facile approach for the fabrication of 2D supermicelle networks.

A novel and facile approach to fabricating well-organized macroscopic 2D networks of cylindrical micelles is reported, based on transfer printing and thermal welding of aligned supramolecular micelles of block copolymers. This versatile approach provides a new strategy for fabricating functional 2D superstructures with a higher level of order.

SPECT/CT Imaging of Pluronic Nanocarriers with Varying Poly(ethylene oxide) Block Length and Aggregation State.

Optimal biodistribution and prolonged circulation of nanocarriers improve diagnostic and therapeutic effects of enhanced permeability and retention-based nanomedicines. Despite extensive use of Pluronics in polymer-based pharmaceuticals, the influence of different poly(ethylene oxide) (PEO) block length and aggregation state on the biodistribution of the carriers is rather unexplored. In this work, we studied these effects by evaluating the biodistribution of Pluronic unimers and cross-linked micelles with different PEO block size.

Interactions of Pluronic nanocarriers with 2D and 3D cell cultures: Effects of PEO block length and aggregation state.

This work reveals how the physicochemical properties of Pluronic block copolymers influence significantly their interactions with cancer cells, whether in monolayer or spheroid cultures, and how different clinical applications can be foreseen. Two-dimensional (2D) and three-dimensional (3D) cell culture models were used to investigate the interactions of Pluronic carriers with different PEO block length and aggregation state (unimers versus cross-linked micelles) in HeLa and U87 cancer cells. Stabilized micelles of Pluronic P94 or F127 were obtained by polymerization of a crosslinking agent in the micelles hydrophobic core.

Lack of a unique kinetic pathway in the growth and decay of Pluronic micelles.

We report kinetic experiments on dilute brine solutions of P84, P94 and P104 Pluronic copolymer micelles. The growth and the decay of micelles after temperature steps are measured by non-standard time resolved multi-angle photon correlation spectroscopy. Several concurrent mechanisms are at work during the very slow equilibration of solutions, namely insertion/expulsion of unimers, aggregation/dissociation of micellar aggregates, and fusion/budding of micellar aggregates.

Cytotoxicity and internalization of Pluronic micelles stabilized by core cross-linking.

A UV-cross-linkable agent was incorporated and polymerized in Pluronic micelle core to create an interpenetrating polymer network (IPN) of poly(pentaerythritol tetraacrylate). This stabilization prevented micelle disruption below the critical micelle temperature (CMT) and concentration (CMC), while maintaining the integrity of the PEO corona and the hydrophobic properties of the PPO core. The prepared stabilized spherical micelles of Pluronic P94 and F127 presented hydrodynamic diameters ranging from 40 to 50 nm.

Wall slip, shear banding, and instability in the flow of a triblock copolymer micellar solution.

The shear flow of a triblock copolymer micellar solution (PEO-PPO-PEO Pluronic P84 in brine) is investigated using simultaneous rheological and velocity profile measurements in the concentric cylinder geometry. We focus on two different temperatures below and above the transition temperature T{c} which was previously associated with the apparition of a stress plateau in the flow curve. (i) At T=37.