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PDMS-b-PAA block copolymers were synthesized in a two-step procedure. The first step involves atom transfer radical polymerization (ATRP) of the protected ethoxyethyl acrylate (EEA) monomer initiated with α-bromopoly(dimethylsiloxane) (PDMS) ( $$ \bar{M}_{\text{n}} $$ = 10,000 g/mol) macroinitiator. In the second step the synthesized poly(dimethylsiloxane)-b-poly(ethoxyethyl acrylate) (PDMS-b-PEEA) was deprotected by thermal treatment. The aggregation properties of the copolymers were investigated by atomic force microscopy (AFM) and dynamic light scattering (DLS). The influence of the polymer concentration, the length of the PAA block, the (mixed) solvent composition, and annealing on the size and the shape of the aggregates was evaluated. The results show that the aggregate size and morphology can be successfully controlled by tuning the experimental conditions. These copolymers might possibly be used in the preparation of adhesive materials.

Polymers are lightweight, flexible, solution-processable materials that are promising for low-cost printed electronics as well as for mass-produced and large-area applications. Previous studies demonstrated that they can possess insulating, semiconducting or metallic properties; here we report that polymers can also be semi-metallic. Semi-metals, exemplified by bismuth, graphite and telluride alloys, have no energy bandgap and a very low density of states at the Fermi level. Furthermore, they typically have a higher Seebeck coefficient and lower thermal conductivities compared with metals, thus being suitable for thermoelectric applications.We measure the thermoelectric properties of various poly(3,4-ethylenedioxythiophene) samples, and observe a marked increase in the Seebeck coefficient when the electrical conductivity is enhanced through molecular organization. This initiates the transition from a Fermi glass to a semi-metal. The high Seebeck value, the metallic conductivity at room temperature and the absence of unpaired electron spins makes polymer semi-metals attractive for thermoelectrics and spintronics. Refereed/Peer-reviewed

This work is an attempt to investigate viscosities at the nanometer scale. To do so, the tapping mode atomic force microscopy is used on a triblock copolymer exhibiting a well-defined periodic structure at the nanometer scale. Variations of the oscillator amplitude and phase delay as a function of the tip-sample distance are recorded on the glassy and rubbery domains of the copolymer. The experimental data are compared to analytical expressions derived from Stokes law. In the present study, among the different possible expressions of the viscous forces depending on the tip shape and on the experimental length scale, only a force proportional to the indentation depth is able to describe the experimental data. In this particular case, quantitative measurements are possible. Finally, the oscillator is shown to be sensitive to local variations of the viscosity within few nanometers.

Thin copper films are deposited onto glass and irradiated, in air, by means of a scanned Ar+ laser beam. The kinetics of oxidation are measured by an interferometric method. The laser-synthesized oxide films are characterized by optical microscopy, scanning tunneling microscopy, and optical spectroscopy. It is shown that the oxidation kinetics, as well as the structural and optical properties of the oxide, depend on the laser beam power and on the initial thickness of the copper film. It is argued that these facts are related to the thermal history of the samples under laser irradiation.

Nature Materials 13, 190–194 (2014); published online 8 December 2013; corrected after print 16 April 2014. In the version of this Article originally published, the grazing incidence wide-angle X-ray scattering (GIWAXS) pattern shown in Fig. 2c was obtained for a contaminated thin-film sample. The correct scattering pattern and caption is given here.

Atomic Force Microscopy (AFM) and related techniques are used to investigate the morphology of diblock copolymers. We focus on compounds containing a conjugated segment, polyparaphenylene, associated to a polymethylmethacrylate or a polystyrene block. The influence of the presence of the conjugated segment on the microdomain morphology is analyzed as a function of chain composition. Separate microdomains are observed on the surface of thin films by means of phase-detection imaging tapping-mode AFM. Their shape and size are interpreted in terms of molecular aggregation, with the help of molecular dynamics calculations.

Conducting polymer composites, that consist of a conducting filler randomly distributed throughout an insulating polymer or polymer blend, attract interest in several application fields such as sensors or electromagnetic radiation shielding. The macroscopic electrical resistivity of the filled polyblend strongly depends on the localization of the filler. Here, we investigate the morphology of Carbon Black (CB)-filled polymer blends in order to determine the parameters governing the selective localization of CB in one phase of the blend components or at the interface between the components. The dispersion of the CB particles in the polymer blend is observed by means of Lateral Force Microscopy (LFM) as a function of the blend composition and the load in C.B. The selective localization of CB at the interface enables the reduction of the percolation threshold down to 0.5 wt%; as a result, the mechanical properties of the polymer blend can be fully retained. Different techniques can be used to locate the CB at the interface; we compare their efficiency experimentally.

Atomic Force Microscopy with Phase Detection Imaging is used to study the surface microdomain morphology of thick (i.e., ca. 2 mm) films of triblock copolymers, such as polymethylmethacrylate - block - polybutadiene - block - polymethylmethacrylate copolymers prepared by a well-taylored two-step sequential copolymerization promoted by a 1,3-diisopropenylbenzene based difunctional anionie initiator. By means of this new scanning probe microscopy technique, it is shown that the surface exhibits a segregated microphase structure, corresponding to the different types of components predicted theoretically by thermodynamic processes. We investigate the relationships between the size and characteristics of the microdomain structure as a function of the molecular parameters of the constituent polymers. Our data illustrate the interest of Phase Detection Imaging in the elucidation of surface phase separation in block copolymers.

Electrochemical polymerization is used to achieve carbon-fibre coatings with heteroaromatic conducting compounds, such as polypyrrole or polyindole. The coated-fibres surfaces are characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The resulting chemical and mechanical properties are studied and this new material is tested as a reinforcement agent in an epoxy resin matrix.