Redox-active dendrimer films

FROM THE SOLUTION THE SOLID STATE ELECTROCHEMISTRY OF REDOX-ACTIVE DENDRIMER FILMS... 

Slmer. Electrochemical treatment of the Slmer provides a photo-sensitive and redox-active dendrimer film-coated electrode. 

Cyclic voltammetric studies of these metallodendrimers showed one reversible oxidation wave, characteristic of independent, non-interacting redox centers. Also, the use of these materials for the modification of electrode surfaces was explored [37-39]. The researchers found that platinum, glass, and carbon-disk electrodes modified by electrodeposited films of these dendrimers are extremely durable and reproducible, with no detected loss of electroactivity even after their use in different electrolyte solutions or after standing for long periods in air. Studies on the thermodynamics and kinetics of adsorption of these redox-active dendrimers onto Pt electrodes by means of electrochemical and electrochemical quartz crystal microbalance techniques were conducted. These showed the adsorption processes to be activation-controlled rather than diffusion-controDed, and to be dependent on... 

Redox-active Dendrimers in Solution and as Films on Surfaces... 

Thermal treatment of the nanocomposite film formed in Scheme 6 converts the amic acid groups of the film to imides (Eq. 15). In addition to evidence by IR spectroscopy, elhpsometry showed that the film thickness decreased by ca. 15% and contact angle goniometry showed that the film became more hydrophobic (see Table 2). This thermally treated film also did not have the pH dependent permeability of redox-active ions previously described for dendrimer/Gantrez films on gold substrates [55]. 

Poly(propylene amine) dendrimers containing 4, 8, and 64 amidoferrocene peripheral units have also been incorporated in the highly ordered channels of mesoporous silica obtaining a novel type of redox-active materials. One significant feature of these new composite materials is that the ferrocene units of the guest dendrimers are easily accessible to electrochemical oxidation, as revealed by studies carried out in MeCN solutions by using Pt electrodes derivatized with films of such dendrimer-matrix complexes.33... 

Different stimuli could trigger the transition of the smart polymer making it possible to produce membranes whose permeabihties respond to these stimuh. When a copolymer of NIPAAM with triphenylmethane leucocianide was grafted to the membrane, it acquired photosensitivity—uv irradiation increases permeation through the membrane (78). Fully reversible, pH-switchable permselectivity for both cationic and anionic redox-active probe molecules was achieved by depositing composite films formed from multilayers of amine-terminated dendrimers and poly(maleic anhydride-co-methylvinyl ether) on gold-coated silicon (79). 

---