Solvent-casting

Polymeric films can be prepared at the surface of metal, glassy carbon, as well as carbon paste electrodes. The preparation of conducting polymers at the surface of carbon electrodes employed in biosensors is already reviewed [1]. The methods mostly used are solvent casting, spin coating, and electropol5mierization. [Pg.330]

In solvent casting method an already prepared polymer is first dissolved in the appropriate solvent and then simply cast onto the surface of the electrode. After solvent evaporation, the film of polymer is formed, ft is a very simple approach, but unfortunately two disadvantages have to be considered, uniformity of the polymeric film and reproducibility of its preparation [2]. This method is usually used for the preparation of redox active or nonconducting polymers [3]. Coatings of composites of nanomaterials with polymers are also often prepared by this method [4]. [Pg.330]

However, this method was successfully used for the preparation of the film of poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrene sulfonic acid) (PSS) at the surface of ITO electrodes [6] and for the preparation of immunosensors based on conjugated poly(phenylene vinylene) derivatives of defined thickness [7]. [Pg.331]

Fig. 12. Schematic of a polymer-coated crosslinked PDMS cap in contact with a polymer-coated flat surface. The PDMS cap is oxidized in 02-plasma, and the polymer layer is coated by solvent casting. On flat surface, the polymer layer is spin coated.

Fig. 5. Transmission IR spectra of natural rubber, solvent cast from xylene, (a) Before heating, and (b) after heating at I70°C for 30 min [62],...

TPEs from blends of rubber and plastics constitute an important category of TPEs. These can be prepared either by the melt mixing of plastics and rubbers in an internal mixer or by solvent casting from a suitable solvent. The commonly used plastics and rubbers include polypropylene (PP), polyethylene (PE), polystyrene (PS), nylon, ethylene propylene diene monomer rubber (EPDM), natural rubber (NR), butyl rubber, nitrile rubber, etc. TPEs from blends of rubbers and plastics have certain typical advantages over the other TPEs. In this case, the required properties can easily be achieved by the proper selection of rubbers and plastics and by the proper change in their ratios. The overall performance of the resultant TPEs can be improved by changing the phase structure and crystallinity of plastics and also by the proper incorporation of suitable fillers, crosslinkers, and interfacial agents. [Pg.634]

Experimental information for polymeric LED is sparse. A key problem for conventional lime-of-flighl studies is that the condition of generating a sheet of carriers whose spatial extension is small compared to the thickness of a = 100 nm film is difficult to meet. On the other hand, thick films fabricated, for instance, by solvent casting rather than by spin coating, may differ regarding their morphology and, concomitantly, the built-in-disorder. On the fundamental side, transport in... [Pg.212]

Ogata et al. (1997) first prepared PLA/ organoclay (OMMT) blends by dissolving the polymer in hot chloroform in the presence of dimethyl distearyl ammonium modified MMT (2Ci8MMT). XRD results show that the silicate layers forming the day could not be intercalated in the PLA/MMT blends, prepared by the solvent-cast method. Thus, the clay existed in the form of tactoids, consisting several stacked silicate monolayers. [Pg.36]

In later work, PEO and PCL PUs were blended by simple mixing to form three-dimensional sponges using solvent cast/particulate leaching methods. [Pg.236]

Insulin (molecular weight 7000) has been formulated in controlled release microbeads and pellets (135,136). A solvent evaporation micro-encapsulation procedure was used to produce microspheres with up to 20% by weight insulin. Solvent-casting techniques were used to prepare pellets. The investigations demonstrated that the PLA... [Pg.29]

The mechanical properties of tyrosine-derived poly(iminocarbon-ates) were investigated using the procedures described in ASTM standard D882-83 (Table 2). Solvent-cast, thin polymer films were prepared, cut into the required shape, and tested in an Instron stress strain tester. Since the films were unoriented, noncrystalUne samples, the results are representative of the bulk properties of the polymers. In order to put these results into perspective, several commercial polymers were tested under identical conditions. In addition, some literature values were included in Table 2. [Pg.222]

In order to test the tissue compatibility of tyrosine-derived poly-(iminocarbonates), solvent cast films of poIy(CTTH) were subcutaneously implanted into the back of outbread mice. In this study, conventional poly(L-tyrosine) served as a control (42). With only small variations, the experimental protocol described for the biocompatibility testing of poly(N-palmitoylhydroxyproline ester) (Sec. III. [Pg.223]

Since poly(L-tyrosine) cannot be processed into shaped devices, compressed pellets rather than solvent cast films were used as control implants. Poly(L-tyrosine) formed strikingly yellow, moderately inflamed patches that remained at the implantation site throughout the 1-year study. Contrary to soluble proteins or peptides that ar rapidly degraded by enzymes, implants of conventional poly(L-tyro-sine) were evidently nondegradable over a 1-year period. At wee 56 all poly(L-tyrosine) implants were infiltrated by a moderate n ber of inflammatory cells. [Pg.223]

Poly(CTTH) (Figs. 6 and 7) was also used as a model compound for the preliminary evaluation of the in vitro degradability of tyro-sine-derived poly(iminocarbonates) Solvent cast films of poly(CTTH)... [Pg.223]

The electrochemical behavior of the C70 solvent-cast films was similar to that of the C60 films, in that four reduction waves were observed, but some significant differences were also evident. The peak splitting for the first reduction/oxidation cycle was larger, and only abont 25% of the C70 was rednced on the first cycle. The prolate spheroidal shape of C70 is manifested in the II-A isotherm of C70 monolayers. Two transitions were observed that gave limiting radii consistent with a transition upon compression from a state with the long molecnlar axes parallel to the water snrface to a state with the long molecnlar axes per-pendicnlar to the water surface. [Pg.109]

C60 has been used to produce solvent-cast and LB films with interesting photoelec-trochemical behavior. A study of solvent-cast films of C60 on Pt rotating disc electrodes (RDEs) under various illumination conditions was reported [284]. Iodide was used as the solution-phase rednctant. The open-circuit potential shifted by 74 mV per decade of illumination intensity from a continuous wave (cw) argon-ion laser. The photocurrent versus power was measured at -0.26 V under chopped illumination (14-Hz frequency, vs. SCE) up to 30 mW cm and was close to linear. The photoexcitation spectrum (photocurrent versus wavelength) was measured at 0.02 V (vs. SCE) from 400 to 800 mn and found to be... [Pg.110]

Solvent extracts" Cast directly on the KBr and evaporate solvent Cast on to silicon wafer Large areas can be coated, no moisture absorption and no interfering peaks... [Pg.314]

Mechanical Properties. The mechanical properties of thin, solvent-cast polymer films were measured on an Instron Tensile Tester according to ASTM standard D882-83. In all cases, tensile values were calculated from the average of at least four measurements obtained from four separate specimens per polymer sample. [Pg.157]

Solvent-cast films of tyrosine-derived polyiminocarbonates and polycarbonates were virtually indistinguishable in appearance and exhibited similar morphological features. When examined by X-ray diffraction, using an automated Scintag Pad V diffractometer all tested films were found to be completely amorphous. The lack of ordered domains in solvent-cast films seemed to be a general feature of tyrosine-derived polyiminocarbonates and polycarbonates, irrespective of the pendent chain configuration of the monomeric dipeptide. [Pg.165]

The tensile properties (tensile strength, Young s modulus, and elongation) of unoriented, noncrystalline films were investigated for those polymers that formed clear films by solvent casting. The results collected in Table I allowed several general conclusions. [Pg.165]

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