Polymer solution deposition

Many experimental studies have also been conducted in order to infer the correlation between the film thickness and the process and liquid parameters [59-69]. It has been observed that the angular velocity, concentration of the polymer solution, viscosity of the solution and rate of solvent evaporation, solvent diflusivity and solvent volatility considerably affect the final thickness of the polymer film. The parameters, such as the amount of polymer solution deposited, the rate of deposition, the initial angular velocity and the time required for spinning, were not found to influence the final film thickness considerably [10]. 

Ammonia—Gas-Cured Flame Retardants. The first flame-retardant process based on curing with ammonia gas, ie, THPC—amide—NH, consisted of padding cotton with a solution containing THPC, TMM, and urea. The fabric was dried and then cured with either gaseous ammonia or ammonium hydroxide (96). There was Httle or no reaction with cellulose. A very stable polymer was deposited in situ in the cellulose matrix. Because the fire-retardant finish did not actually react with the cellulose matrix, there was generally Httle loss in fabric strength. However, the finish was very effective and quite durable to laundering. 

Alternatively, the amount of polymer deposited can be determined via droplet evaporation by microsyringe application of known amounts of polymer solution on the electrode surface, but the problem of homogeneity of the film is still not solved. 

An alkali halide (NaCl, KCl, KBr, etc.) which has a freshly cleaved (001) face is introduced into a polymer solution and then the pol5nner is to be crystallized epitaxially onto the face of the alkali halide. In general, flexible-chain polymers are apt to be crystallized as rod-like crystals on such an alkali halide these rod-like crystals are edge-on lamellae with their lateral surface being mostly in contact with the (001) face of the alkali halide. A given polymer deposited on an alkali halide can be melted and subsequently crystallized there in an epitaxial fashion. 

Evaluation of the Copolymers The polymer solutions were evaluated for their deposit control and dispersant activities. The tests included calcium phosphate inhibition, calcium carbonate inhibition, iron oxide dispersion, and clay dispersion. The procedures for these tests have been previously reported (12). A commercially available polyacrylic acid was also tested for comparison. The results are shown in Tables II to V. 

Different approaches to obtain wrinkles in thin polymer sheets were presented by Harrison and Stafford [53, 54], Thin polyethylene (PE) sheets were first spin-coated onto silicon wafers and subsequently transferred to a relatively thick slab of PDMS by releasing the film in water. This technique takes advantage of the tunable film thickness by the spin-coating process (spin velocity, concentration of polymer solution) as well as the water-insoluble nature of PE. Wrinkles were induced by either compressing the PDMS-PE-bilayer setup [54] or depositing the PE-sheet onto a prestrained PDMS slab and releasing the strain afterwards [53],... 

POEA), a conducting polymer. The measurements were carried out using both solution and polymer films deposited by the self-assembly technique (Paterno and Mattoso, 2001). Figure 16.21 presents the Raman spectra of FA, POEA, and POEA/ FA complexes in different concentrations of FA. 

Fig. 1 LbL film deposition on a planar support. Immersion in polymer solutions of polycation (a) and polyanion (c). (b, d) Washing steps to remove nonadsorbed polymer molecules, (e) Structure of the LbL-assembled film...

Film Fabrication. The platinum electrode (0.28 cm area) was fabricated and cleaned as previously described (19). Thin films of AQ-enzyme were prepared by dissolving an amount of the enzyme, as indicated below, in 10 il of 1.5% AQ polymers solution at room temperature. Two aliquots of 5 il were deposited atop the platinum electrode and the first aliquot was allowed to dry before the second addition. This procedure corresponds to the first protocol. In addition, for the second protocol, 10 il of the 0.5% Nafion solution was casted atop the dried AQ-enzyme film and the methanol was allowed to evaporate at room temperature. The third protocol consisted in the deposition of 10 il of a 1% of AQ solution containing the enzyme, atop the platinum electrode followed by heating in an oven at 50°C during 30 min. In each case, 2 U of glucose oxidase were used. 

In solution, the UV absorption characteristics of polygermanes may be different from those in the solid state. Poly(dihexyl)germane in solution has a kmax value of 327 nm, whereas the same polymer fraction deposited as a thin film on a quartz plate exhibits two... 

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