Poly ultrathin film

With appropriately substituted oxetanes, aluminum-based initiators (321) impose a degree of microstmctural control on the substituted polyoxetane stmcture that is not obtainable with a pure cationic system. A polymer having largely the stmcture of poly(3-hydroxyoxetane) has been obtained from an anionic rearrangement polymerisation of glycidol or its trimethylsilyl ether, both oxirane monomers (322). Polymerisation-induced epitaxy can produce ultrathin films of highly oriented POX molecules on, for instance, graphite (323). Theoretical studies on the cationic polymerisation mechanism of oxetanes have been made (324—326). 

Poly[(p-butoxyphenyl)phenylsilane] (PBPPS) has been employed as an emissive layer of an organic EL device.95 PBPPS was spin coated onto an uniaxially oriented poly(diethylsilane) (PDES) ultrathin film. Polarized NUV-EL was observed and the polarization direction was found to be identical with the drawing direction of the friction-transfer process for the PDES film, indicating that PBPPS in the emissive layer was aligned parallel to the uniaxial orientation of PDES. 

The use of an SECM to probe the surface conductivity of ultrathin films has been proposed [162]. Lateral conductivity of poly(3-hexylthiophene) films containing gold nanoparticles in addition was measured with an SECM in the feedback mode [163]. 

Bagrov, D. V. et al. Amorphous and semicrystaUine phases in ultrathin films of poly(3-hydroxybutirate). TechCormect World NTSI-Nanotech 2012 Proceedings, ISBN 978-1-4665-6274-5, 2012,1, 602-605. 

Ultrathin films in the nanometer range of poly(metal tetrathiooxalates) (M = Cu(II), Ni(II), Pd(II), Co(II)) have been prepared by sequential adsorption of divalent metal cations and tetrathiooxalate dianions on charged substrates (quartz slides with an upper layer of poly(allylamine hydrochloride) as shown in Eq. 7-11 [70]. Non-modified ITO glass or ZnSe substrates have also been also used. The modified quartz slide was dipped alternately into aqueous solutions of the tetrathiooxalate and a metal salt, and cleaned in between. The dark-brownish layers show a very broad absorption extending from the UV to the NIR. The electrical conductivities are in the order of 10 S cm" . 

Lvov Y, Decher G, Mohwald H. 1993. Assembly, structural characterization, and thermal behavior of layer by layer deposited ultrathin films of poly(vinyl sulfate) and poly (aUylamine). Langmuir 9 481 486. 

Recently, ultrathin films of poly(o-anisidine) and poly(ethoxyaniline) have been fabricated for application in nanotechnology [64-66]. Matsura and co-workers [67] have fabricated monolayers of 3-carotene using a Langmuir-Blodgett film technique together with the flow-orientation method. They have utilised XRD, UV-visible and FTIR techniques to elucidate the film-structure of P-carotene indicating that P-carotene orients perpendicular to the air-water interface. It was found that the films are, however, well-ordered both in the stacking direction and the in-plane direction. 

First, examples of fluorescence [235] and chemiluminescence-based biosensors [236], derived fix)m PTs, were reported by Tripathy and coworkers. Later, the synthesis of 119 containing pendant biotin units was described. A water-soluble copolymer 120 with sulfonate and biotin in the side chains [237] exhibits a deep violet color (Amax = 550 run) which turns yellow (A ax = 400 nm) on binding with avidin. An extension of this work based on the homopolymer 121 involved the preparation of monolayers of a biotinylated PT on an aminosilane-treated ITO surface by successive deposition of 121 and biocytin hydrazide in electrostatic interactions [238,239]. This ultrathin film modified electrode was shown to detect femtomoles of avidin in aqueous solution. Electrochemical and optical evidences for avidin binding were reported for a copolymer based on poly(terthiophene) 122 [240] and for the homopolymer 123 [198]. 

Carpick, R.W., T.M. Mayer, D.Y. Sasaki, and A.R. Bums. 2000. Spectroscopic ellipsometry and fluorescence study of thermochromism in an ultrathin poly(diacetylene) film Reversibility and transition kinetics. Langmuir 16 4639. 

Previous studies reveal the direct ECL detection of DNA in poly(vinylpyridine) (PVP) ultrathin film using cationic polymer [Ru(bpy)2(PVP)io] " or [Os(bpy>2 (PVP)io] " [152]. DNA damage from benzo[a]pyrene metabolites using ECL arrays suitable for genotoxicity screening was also demonstrated later [23]. 

The formation and characterization of ultrathin film formed by poly(3-amino-benzoic acid) (PABA) was carried out by Sriwichai et al. [55] using ESPR for the development of immunosensor to detect human immunoglobulin G. With the aid of simultaneous measurements of SPR and CV it has been become possible to calculate the thickness and dielectric properties of a polymeric film, allowing that immunosensor responses can be related to its surface morphology. Another ESPR biosensor also based on PABA was developed by Baba et al. [56] to detect adrenaline. The polymer acts as a specific reaction site for adrenaline, presenting different electrochemical and SPR responses to those for uric and ascorbic acids, which are major interferences of the catecholamine studied. The two techniques were used to evaluate the electrodeposition of PABA and to obtain the calibration curves and the detection limit was set to 100 pmol... 

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