New developments in electrografting of thin polymer films

Conference (2006, June)

Electrografting of thermo-responsive polymer film on conductive substrate

Poster (2006, May 18)

A generic platform for SPM-based molecular recognition processes and stiluli-responsive probes

Poster (2006, May 18)

Structure and morphology of thin films of fulorinated copolymers

Poster (2006, May 18)

Surface modification of metallic cardiovascular stents by strongly adhering aliphatic polyester coatings

in Journal of Biomedical Materials Research, Part A (2006), 76(3), 521-529

This article reports on a novel two-step strategy for the coating of cardiovascular stents by strongly adhering biocompatible and biodegradable aliphatic polyesters. First, a precoating of poly ... [more ▼]

This article reports on a novel two-step strategy for the coating of cardiovascular stents by strongly adhering biocompatible and biodegradable aliphatic polyesters. First, a precoating of poly(ethylacrylate) (PEA) was electrografted onto the metallic substrate by cathodic reduction of the parent monomer in dimethylformamide (DMF). The electrodeposition of PEA, in a good solvent of it, was confirmed by both Infra-red and Raman spectroscopies. The pendant ester groups of PEA were then chemically reduced into aluminum alkoxides, able to initiate the ring-opening polymerization (ROP) of either D,L-lactide (LA) or epsilon-caprolactone (CL). Growth of biodegradable PLA or PCL coatings from the adhering precoating was confirmed by both Infra-red and Raman spectroscopies, and directly observed by scanning electron microscopy (SEM). This type of coating can act as an anchoring layer for the subsequent casting of drug-loaded polyester films allowing the controlled release of antiproliferative agents for the treatment of in-stent restenosis. [less ▲]

Combination of electrografting and atom-transfer radical polymerization for making the stainless steel surface antibacterial and protein antiadhesive

in Langmuir (2006), 22(1), 255-262

A two-step "grafting from" method has been successfully carried out, which is based on the electrografting of polyacrylate chains containing an initiator for the atom transfer radical polymerization (ATRP ... [more ▼]

A two-step "grafting from" method has been successfully carried out, which is based on the electrografting of polyacrylate chains containing an initiator for the atom transfer radical polymerization (ATRP) of 2-(tert-butylamino)ethyl methacrylate (TBAEMA) or copolymerization of TBAEMA with either monomethyl ether of poly(ethylene oxide) methacrylate (PEOMA) or acrylic acid (AA) or styrene. The chemisorption of this type of polymer brushes onto stainless steel surfaces has potential in orthopaedic surgery. These films have been characterized by ATR-FTIR, Raman spectroscopy, atomic force microscopy (AFM), and measurement of contact angles of water. The polymer formed in solution by ATRP and that one detached on purpose from the surface have been analyzed by size exclusion chromathography (SEC) and H-1 NMR spectroscopy. The strong adherence of the films onto stainless steel has been assessed by peeling tests. AFM analysis has shown that addition of hydrophilic comonomers to the grafted chains decreases the surface roughness. According to dynamic quartz crystal microbalance experiments, proteins (e.g., fibrinogen) are more effectively repelled whenever copolymer brushes contain neutral hydrophilic (PEOMA) co-units rather than negatively charged groups (PAA salt). Moreover, a 2- to 3-fold decrease in the fibrinogen adsorption is observed when TBAEMA is copolymerized with either PEOMA or AA rather than homopolymerized or copolymerized with styrene. Compared to the bare stainless steel surface, brushes of polyTBAEMA, poly (TBAEMA-co-PEOMA) and poly(TBAEMA-co-AA) decrease the bacteria adhesion by 3 to 4 orders of magnitude as revealed by Gram-positive bacteria S. aureus adhesion tests. [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 ▲]

Multi-biomaterial for controlled release of active substances

Poster (2006)

Combination of ring-opening polymerization and "click" chemistry towards functionalization of aliphatic polyesters

in Chemical Communications (2005), (42), 5334-5336

Azide pendent groups of aliphatic polyesters have been derivatized into tertiary amines, ammonium salts and poly(ethylene oxide) grafts. The experimental conditions have been optimized (organic solvent ... [more ▼]

Azide pendent groups of aliphatic polyesters have been derivatized into tertiary amines, ammonium salts and poly(ethylene oxide) grafts. The experimental conditions have been optimized (organic solvent, 35 degrees C), such that the aliphatic polyesters are not degraded, including even poly(lactide) which is very sensitive to attack by weak nucleophiles. [less ▲]

Tailoring of thin polymer films chemisorbed onto conductive surfaces by electrografting

in Urban, Marek W (Ed.) Stimuli-responsive polymeric films and coatings (2005)

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 to deposition of very thin polymer films, recent developments have overcome these limitations. First of all, the judicious choice of the solvent has proved to be a powerful lever to increase the range of the chemisorbed polymers, including functional polymers. Quite interestingly, classical controlled polymerization techniques have been combined with cathodic electrografting as a powerful strategy for tuning thickness, properties and reactivity of the chemisorbed organic films. At the time being, cathodic electrografting has contributed to substantial progress in very demanding applications, such as protection against corrosion, food packaging, biomaterials, sizing of reinforcing agents in polymer composites and sensoring devices. [less ▲]