Cathodic electrografting of acrylics: From fundamentals to functional coatings

in Progress in Polymer Science (2010), 35

Promoting permanent adhesion between so dissimilar materials as polymers and metals is a very challenging target and a severe brake to the implementation of many potential applications. However, synthetic ... [more ▼]

Promoting permanent adhesion between so dissimilar materials as polymers and metals is a very challenging target and a severe brake to the implementation of many potential applications. However, synthetic polymers can now be chemisorbed onto a variety of conducting surfaces by cathodic electrografting of acrylic monomers. The first part of this review will focus on the fundamental aspects of this emerging technology, thus from the historical discovery to experimental and theoretical developments, with the purpose to better comprehend the electrografting phenomenon. Once firmly established, this concept has been exploited in order to make polymeric coatings with specific functionality chemisorbed onto more diversified substrates in more convenient liquid media. This remarkable progress that largely relies on advanced controlled polymerization processes will be the topic of the second part of the review, with a special emphasis on the more recent development of smart coatings, particularly stimuli responsive coatings very well-suited to nanotechnologies. [less ▲]

Modification of AFM probes with polymers: biosensors and actuators

Poster (2008, May 22)

Atomic force microscopy investigation of the morphology and the biological activity of protein-modified surfaces for bio- and immunosensors

in Analytical Chemistry (2007), 79(17), 6488-6495

With the purpose of developing biosensors, the reliable proof of the biological activity of two new sensor systems was obtained by atomic force microscopy (AFM) in both the imaging and the single-molecule ... [more ▼]

With the purpose of developing biosensors, the reliable proof of the biological activity of two new sensor systems was obtained by atomic force microscopy (AFM) in both the imaging and the single-molecule force spectroscopy modes. Antigens or antibodies of pharmacological interest were grafted onto self-assembled monolayers of thiols on gold, and AFM imaging demonstrated that the grafting process produced homogeneous submonolayers of isolated proteins. The analysis of the morphology of the surfaces at the different functionalization steps allowed evaluating the protein grafting density and showed that the recognition of complementary species present in the surrounding solution occurred. Single-molecule force spectroscopy experiments between the sensing surfaces and AFM probes, onto which the complementary species were grafted, enabled a direct and rapid test of the biological activity of the sensors by investigating the interaction occurring at the level of one single ligand-receptor bond. Ellipsometry and surface plasmon resonance allowed further characterization of the sensor surfaces and confirmed that the biological recognition took place. [less ▲]

One-step polymer grafting from silicon nitride SPM probes: From isolated chains to brush regime

in Journal of the American Chemical Society (2007), 129(27), 8410

We show that a reactive polymer can be directly grafted from commercial Si3Nx SPM tips, without any intermediate layer. The conditions can be chosen to achieve either an isolated mushroom regime, with ... [more ▼]

We show that a reactive polymer can be directly grafted from commercial Si3Nx SPM tips, without any intermediate layer. The conditions can be chosen to achieve either an isolated mushroom regime, with only one or a few chains accessible at the tip apex, or a brush regime. [less ▲]

Synthesis of adherent hydrophilic polypyrrole coatings onto (semi)conducting surfaces

in Chemistry of Materials (2007), 19(9), 2364-2371

Hydrophilic and adherent polypyrrole coatings were prepared by a two-step electrochemical method. First, alpha-pyrrole, omega-acrylate polyethylene oxide (Py-PEO-A) dual macromonomer was synthesized by ... [more ▼]

Hydrophilic and adherent polypyrrole coatings were prepared by a two-step electrochemical method. First, alpha-pyrrole, omega-acrylate polyethylene oxide (Py-PEO-A) dual macromonomer was synthesized by anionic polymerization and electrografted onto (semi)conducting substrates by cathodic polymerization of the acrylic end-group. The obtained adherent coating is hydrophilic and thus swells in water and bears a pyrrole ring, a precursor of the conducting polymer. In a second step, the coating is anodically polarized in a mixture of Py and Py-PEO to give the hydrophilic and adherent polypyrrole. Properties such as morphology, adherence, electroactivity, and hydrophilicity of these coatings were investigated by conventional methods and compared to those of pure polypyrrole coatings. These novel coatings exhibit efficient protein adsorption repellency and are thus good candidates for applications in biomaterials and biosensors. [less ▲]

First insights into electrografted polymers by AFM-based force spectroscopy

in Macromolecules (2006), 39(24), 8428-8433

The very first characterization of the structural properties of polymer films obtained by electrografting is reported. AFM-based force spectroscopy was used to investigate poly-N-succinimidyl acrylate ... [more ▼]

The very first characterization of the structural properties of polymer films obtained by electrografting is reported. AFM-based force spectroscopy was used to investigate poly-N-succinimidyl acrylate (PNSA) layers electrografted directly from a silicon substrate. Quantitative analysis of compression profiles obtained in a good solvent and single molecule bridging interaction, in light of the Alexander-de Gennes model, gave access to the grafting density and degree of polymerization. A high swelling capacity has been evidenced. This report is the first evidence that polymers obtained by cathodic electrografting are in fact brush systems, and consequently the first evidence that a polymer brush can be obtained from a direct "grafting from" method, without any intermediate layer. [less ▲]

Electrografting of thermo-responsive polymer film on conductive substrate

Poster (2006, May 18)

Electrografting of thin polymer films: Three strategies for the tailoring of functional adherent coatings

in Progress in Organic Coatings (2006), 55(2), 175-181

Cathodic electrografting is an efficient technique to impart adhesion to poly(meth)acrylate coatings onto inorganic conducting surfaces. Although this technique was restricted for many years to very few ... [more ▼]

Cathodic electrografting is an efficient technique to impart adhesion to poly(meth)acrylate coatings onto inorganic conducting surfaces. Although this technique was restricted for many years to very few monomers ((meth)acrylonitrile and (meth)acrylates) and to deposition of very thin polymer films, recent developments have overcome these limitations. First of all, classical controlled/living polymerization techniques have been combined with cathodic electrografting as a powerful strategy for tuning thickness, properties and reactivity of the chemisorbed organic films. Secondly, thanks to the successful electrografting of a new reactive monomer bearing an activated ester, electrografted surfaces are now available for further derivatization by a wide variety of nucleophiles. Finally, the electrografting process has been extended to the direct electrografting of reactive polymers, i.e. preformed polymers beating pendant acrylic functions, which opens the way to the grafting of, e.g., polycondensates. [less ▲]

Mechanochemistry: targeted delivery of single molecules

in Nature Nanotechnology (2006), 1

The use of scanning probe microscopy-based techniques to manipulate single molecules1 and deliver them in a precisely controlled manner to a specific target represents a significant nanotechnological ... [more ▼]

The use of scanning probe microscopy-based techniques to manipulate single molecules1 and deliver them in a precisely controlled manner to a specific target represents a significant nanotechnological challenge. The ultimate physical limit in the design and fabrication of organic surfaces can be reached using this approach. Here we show that the atomic force microscope (AFM), which has been used extensively to investigate the stretching of individual molecules, can deliver and immobilize single molecules, one at a time, on a surface. Reactive polymer molecules, attached at one end to an AFM tip, are brought into contact with a modified silicon substrate to which they become linked by a chemical reaction. When the AFM tip is pulled away from the surface, the resulting mechanical force causes the weakest bond — the one between the tip and polymer — to break. This process transfers the polymer molecule to the substrate where it can be modified by further chemical reactions [less ▲]

Electrografting of Poly(ethylene glycol) Acrylate : A One-Step Strategy for the Synthesis of Protein-Repellent Surfaces

in Angewandte Chemie (International ed. in English) (2005), 44(34), 5505-5509

Electrografting of acrylate end-capped poly(ethylene glycol) (PEG) is an important technique for the one-step coating of electroconductive substrates by an adherent hydrophilic coating (see figure). This ... [more ▼]

Electrografting of acrylate end-capped poly(ethylene glycol) (PEG) is an important technique for the one-step coating of electroconductive substrates by an adherent hydrophilic coating (see figure). This technique is very efficient for the production of new protein-repellent surfaces. [less ▲]