The Watson-Crick binding of DNA single strands is a powerful tool for the assembly of nanostructures. Our objective is to develop polymer nanoparticles equipped with DNA strands for surface-patterning applications, taking advantage of the DNA technology, in particular, recognition and reversibility. A hybrid DNA copolymer is synthesized through the conjugation of a ssDNA (22-mer) with a poly(ethylene oxide)-poly(caprolactone) diblock copolymer (PEO-b-PCl). It is shown that, in water, the PEO-b-PCl-ssDNA(22) polymer forms micelles with a PCl hydrophobic core and a hydrophilic corona made of PEO and DNA. The micelles are thoroughly characterized using electron microscopy (TEM and cryoTEM) and small-angle neutron scattering. The binding of these DNA micelles to a surface through DNA recognition is monitored using a quartz crystal microbalance and imaged by atomic force microscopy. The micelles can be released from the surface by a competitive displacement event.

This work aims at demonstrating the interest of gradient copolymers in supercritical CO2 in comparison with block copolymers. Gradient copolymers exhibit a better solubility in supercritical CO2 than block copolymers, as attested by cloud point data. The self-assembly of gradient and block copolymers in dense CO2 has been characterized by Small-Angle Neutron Scattering (SANS) and it is shown that it is not fundamentally modified when changing from block copolymers to gradient copolymers. Therefore, gradient copolymers are advantageous thanks to their easier synthesis and their solubility at lower pressure while maintaining a good ability for self-organization in dense CO2.

In this paper we used a surfactant-stabilized lyotropic lamellar model system to study the interfacial behaviour of an ion-extracting agent: N1,N3 dimethyl- N1, N3-dibutyl-2-tetradecyl malonamide (DMDBTDMA). An analysis of small angle X-ray scattering (SAXS) and polarized Attenuated Total Reflectance - Fourier Transform Infra Red (ATR-FTIR) data enabled to describe the distribution of the malonamide extractant within the bilayers and its complexation state at the equilibrium. The lamellar phase was diluted with salt water containing varying amount of complexing salt, and each structural state measured was described using a thermodynamic model based on three elementary equilibria: (i) partition of the extractant polar heads between the core and the polar shell of the bilayers, (ii) the complexation of ions by extractants at the bilayers surfaces, and (iii) the partition of bonded extractants between the core and interfaces of bilayers. This model enabled to compare the energy cost of each step.

The infrared spectra of proline rich proteins display a strong band in the 1450 cm-1 region. In the literature, this band was assigned either to the deformation modes of the CH2 and CH3 groups or to the CN stretching mode of proline residues. In order to establish the correct assignment of this band, the impact of proline vibrations in a polypeptide chain is studied and ab-initio calculations are performed for a model molecule (I) containing a repeat unit of polyproline. A strong band is effectively calculated in the 1450 cm-1 region and mostly assigned to CN stretching whereas, due to the absence of N-H bond, there is no amide II band. These results are in good agreement with the spectral features observed in the FTIR spectra of gliadins. Moreover, the spectral shifts calculated when a water molecule is complexed with (I) are consistent with the hydration effect observed in the experimental data.

We study the nonlinear rheology of a novel class of transient networks, made of surfactant micelles of tunable morphology reversibly linked by block copolymers. We couple rheology and time-resolved structural measurements, using synchrotron radiation, to characterize the highly nonlinear viscoelastic regime. We propose the fluctuations of the degree of alignment of the micelles under shear as a probe to identify a fracture process. We show a clear signature of a brittle-to-ductile transition in transient gels, as the morphology of the micelles varies, and provide a parallel between the fracture of solids and the fracture under shear of viscoelastic fluids.

We report on a continuous droplet interface crossing encapsulation (cDICE) technique for the high-yield production of microscopic vesicles tunable in size and content. Overcoming some of the current technique limitations, such a simple setup has a great potential in various fields from encapsulation to the design of biomimetic cells and artificial tissues.

We study the nematic-smectic phase transition of a thermotropic liquid crystal confined to a spherical shell. Far from the nematic-smectic phase transition temperature, TNS, we observe a configuration with four þ1=2 defects, as predicted by theory. Since in this case K1 ~~ K3, the four defects are confined at the thinnest part of the shell to minimize the energy associated with the defect cores. By contrast, near TNS, where K3 >> K1, bend distortions become prohibited and the defects organize themselves along a great circle of the sphere, confirming recent theoretical and simulation results. During this structural change, the defects associate in two pairs that behave independently. In the smectic phase, we observe a new configuration displaying curvature walls.