Material surface preparation techniques evaluating methods

Ellipsometry is a high-precision optical characterization technique, the potential of which has not yet been sufficiently exploited in polymer science. It is a rapid and nondestructive experimental method for the analysis of surfaces and thin films. Besides the determination of film thickness with high sensitivity ( 0.1 nm), optical parameters related to material properties can also be evaluated [1]. The facts that ellipsometric measurements can be performed under any ambient conditions, and require no special sample preparation procedures, provide a definite advantage over other surface science techniques [2—4]. 

For the evaluation of the SIM technique in chemical sensors application, an experimental set-up was developed as shown in Fig. 31. A fiber-optic chemical sensor was prepared, using polyaniline as the modified cladding for a short MM sensing fiber. The spin-casting method was used for coating a thin layer of polyaniline material on the fiber core surface. Then, the modified fiber was tested for the detection of HCl vapor and NH3 gas. The sensor was tested by both the total intensity modulation and the SIM techniques. 

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