The development of smart nanomaterials has attracted great attention in several fields like nanoscience and nanotechnology due to their unique response to external stimuli. Many of them are based on polymers that can exhibit a shape-changes when submitted to environmental modifications. Poly(N-isopropylacrylamide), PNIPAM, is a thermo-responsive polymer. Linear chains are water soluble at room temperature but undergo a reversible coil-to-globule transition at a lower critical solution temperature (LCST) close to 32°C due to the dehydration and subsequent collapse of its chains into compact globules. [1] This phenomenon results in a volume phase transition (VPT) in PNIPAM based crosslinked microgels and can be used to promote original thermal effects.Hybrid nanocomposite microgels associating PNIPAM and gold nanoparticles (GNP) have thus been designed in order to take advantage of the outstanding plasmonic and photo-thermal properties of GNP to promote the VPT of the microgels through an efficient photo-thermal conversion. [2] With their strong diameter-dependent optical absorption in the near infrared (NIR) and their large surface area favoring photo-thermal transfer, semiconducting single-walled carbon nanotubes (s-SWNT) are also good candidates for photo-thermal conversion in the NIR (Figure 1a). However, to the best of our knowledge, no thorough studies of nanomaterials based on both SWNT and PNIPAM have been reported so far.Here we describe the preparation of SWNT/PNIPAM hybrid microgels through a non-covalent functionalization technique. These nanoparticles are stable in water and show a VPT, which can be promoted either by direct heating or by excitation of the resonant absorption of s-SWNT in the NIR (Figure 1b-c). The photoluminescence (PL) signal can be used to monitor the VPT by a redshift observed when crossing the LCST, while the Raman signatures remain essentially the same.

Isoniazid (INH) is one of the primary drugs used in tuberculosis treatment and its encapsulation in liposomal vesicles can both improve its therapeutic index and minimize toxicity. Here we consider mixtures of hydrogenated soy phosphatidylcholine-phosphatidylglycerol (HSPC-DPPG) to get novel biocompatible liposomes for INH delivery. We determined INH encapsulation efficiency by coupling for the first time UV and Laser Transmission Spectroscopy and we showed that HSPC-DPPG liposomes can load more INH than expected from simple geometrical arguments, thus suggesting the presence of drug-lipid association. To focus on this aspect, which has never been explored in liposomal formulations, we employed several complementary techniques, such as dynamic and static light scattering, calorimetry and surface pressure measurements on lipid monolayers. We find that INH-lipid interaction increases the entrapment capability of liposomes due to INH adsorption. Moreover, the preferential INH-HSPC dipole-dipole interaction promotes the modification of lipid ordering, favoring the formation of HSPC-richer domains in excess of DPPG. Our findings highlight how investigating the fundamental aspects of drug-lipid interactions is of paramount importance for the optimal design of liposomal nanocarriers.

We studied a colloidal suspension of polystyrene beads deposited on a glass substrate. The glass substrate contained either straight rough areas on the borders of an open channel or only straight rough areas. The drying of the suspension was observed with an optical microscope which light bulb acted as an energy source to evaporate the suspension. Moreover, the light bulb of the microscope provided optical pressure due to light. We observed that the colloidal particles where trapped on the rough areas of the substrate and not in the open channel, at the end of the drying process. In order to understand the experimental results, we modelled numerically the drying of the suspension by a Molecular Dynamics program. The forces acting on the substrate by the particles are their weight, the optical pressure due to the light bulb of the optical microscope, the attractive Van der Waals force and the repulsive diffuse layer force. The forces acting between two particles are the attractive Van der Waals forces, the repulsive diffuse layer force, the capillary force. The Gaussian random force (linked to the Brownian motion), the particle liquid viscous drag force (also linked to the Brownian motion) are horizontal and applied on one particle. The relation between the normal forces N (forces acting by the particles on the substrate) and the horizontal forces F is Amontons' third law for friction F ≤ µ k N ; in rough areas of the substrate µ k is larger than in smooth areas. This explains that particles are trapped in the large roughness areas.

The development of smart nanomaterials has attracted great attention in several fields like nanoscience, materials science,engineering and nanotechnology due to their unique response to external stimuli. Many of them are based on polymers thatcan exhibit great shape-changes when submitted to environmental modifications. Poly(N-isopropylacrylamide), PNIPAM, is sucha thermo-responsive polymer. It is water soluble at room temperature, forming gels by cross-linking but undergoes a reversiblecoil-to-globule volume phase transition (VPT) at a lower critical solution temperature (LCST) close to 32 °C due to thedehydration and subsequent collapse of its chains into compact globules.
Hybrid nanocomposite microgels associating PNIPAM and gold nanoparticles (GNP) have been designed in order to takeadvantage of the outstanding plasmonic and photo-thermal properties of GNP to promote the volume phase transition of themicrogels through an efficient photo-thermal conversion. With their strong diameter-dependent optical absorption in the nearinfrared (NIR) and their large surface area favoring photo-thermal transfer, semiconducting SWNT (s-SWNT) are goodcandidates for photo-thermal conversion in the NIR and may therefore be used to prepare multi-responsive hybrid microgels(Figure 1). However, to the best of our knowledge, no thorough studies of such nanomaterials have been reported so far.
Here we report the preparation of smart SWNT/PNIPAM nanocomposites through non-covalent functionalization techniques.These SWNT/PNIPAM hybrid microgels are stable in water and show a VPT, which can be promoted either by direct heating orby excitation of the resonant absorption of s-SWNT in the near infrared. Furthermore, the photoluminescence (PL) signal of s-SWNT is modulated at the phase transition and therefore, the PL signal can be used to monitor the VPT. This is illustrated inFigure 2, showing coupled Raman/PL measurements below and above the LCST, where a redshift of the PL bands is observedwhen crossing the LCST while the Raman signatures remain essentially the same.

Temperature is one of the basic parameters often required to characterize a system. A great demand has arisen for localmeasurements, especially in liquids or complex biological environments. Various approaches have been proposed to study thetemperature at the nano-scale level. Some of them are based on the spectroscopic properties of carbon nanotubes (CNT) usedas sensors.
Raman spectroscopy is indeed a powerful technique to identify single-walled carbon nanotubes (SWNT) and to study theirstructure, defects and electronic properties through the measurement of specific Raman signatures (RBM, D, G and 2D bands).On the other hand, individual SWNT or small bundles emit light in the near infrared and the photoluminescence (PL) spectra isvery sensitive to the quality of the dispersion and the dielectric environment of the nanotubes. In particular, when SWNT aredispersed in aqueous solutions, the PL energies are sensitive to the nature of the surfactants or polymers, to theirconcentration, and to the way they adsorb on/wrap around the nanotubes.
In this work we show that the PL/Raman spectra of SWNT dispersed with sodium dodecyl sulfate (SDS) is very sensitive to thetemperature (figure 1) in a large range of SDS concentrations. We discuss the influence of the chiral angle of the SWNT onthese PL changes, and the origin of the changes in terms of SDS reorganization at the surface of the nanotubes. Similarchanges are obtained with increasing laser power (figure 2), showing the local heating of the nanotubes. These results pavethe way for the development of SWNT-based nano-thermometers.

Downsizing electronic and electric equipment requires the optimization of electric field distributions in order to avoid localized dielectric breakdown (also called partial discharges). This paper presents a novel dielectric composite material aimed at grading electrical local surface stress. This functional material has a conductivity which increases by several orders with the applied electric field giving the ability to distribute the field by itself. It is prepared for the first time by dispersing graphite nanoplatelets in a polymer and may be used as a resistive or capacitive field grading material in electronic and electrical applications. Mechanisms at the origin of the nonlinear behavior are discussed.

Filling carbon nanotubes with molecules is a route for the development of electronically modified one-dimensional hybrid structures for which the interplay between the electronic structure of molecules and nanotubes is a key factor. Tuning these energy levels with external parameters is an interesting strategy for the engineering of new devices and materials. Here we show that the hybrid system composed by quaterthiophene (4T) molecules confined in single-walled carbon nanotubes, presents a piezo-Raman-resonance of the molecule vibrational pattern. This behavior manifests as a rapid pressure induced enhancement of the 4T Raman mode intensities compared to the tubes G-band Raman modes. Density functional theory calculations allow to explain the spectral behaviour through the pressure-enhanced quaterthiophene resonance evolution. By increasing pressure, the tube cross-section deformation leads to a reduction of the intermolecular distance, to the splitting of the molecular levels and then to an increase of resonance channels. Calculations and experiments converge to the 4T piezo-resonance scenario associated with the pressure-induced nanotube radial collapse observed at about 0.8 GPa. Our findings offer possibilities for the development of pressure transducers based on molecule-filled carbon nanotubes.