Stage polymer-, pairs

FIG. 9 Schematic illustration of adsorption of poly(styrenesulfonate) on an oppositely charged surface. For an amphiphile surface in pure water or in simple electrolyte solutions, dissociation of charged groups leads to buildup of a classical double layer, (a) In the initial stage of adsorption, the polymer forms stoichiometric ion pairs and the layer becomes electroneutral, (b) At higher polyion concentrations, a process of restructuring of the adsorbed polymer builds a new double layer by additional binding of the polymer. 

Polymethylmethacrylate is one of the heterogeneous polymer and ESR studies on this polymer have been done from the early stage of ESR spectroscopy ( 5). Russian researchers reported ESR ctra observed from the PMMA mechano-radicals (28,46-48). No ir formation of the n hano radicals was mentioned by these authors, although PMMA is one of the suitable polymers on wludi Ihe ptdr formation of mechano-radicals is s rched. An ESR spectrum (38, 49) observed at 77 K from the PMMA milled for 24 hrs. is shown as a in Fig. 8. It is well known (50,51) that PMMA radical produced by the main chain scission shows the characteristic quintet-quartet spectrum when PMMA is irradiated by y-rays. It is reasonable to assume that one partner of the pair formation of the PMMA mei no-radical is the species. 

NMP TCNQ concentration plot (Fig. 7), it appears that there exist three stages of equilibria in the salt aggregation in the polymer matrix a loose ion-pairing, a tight ion-pairing, and an aggregation ... 

One simple approach has been that of Cole et al. who propose the use of two sensors run in a ratiometric mode [12]. Figure 9 shows a CMOS chip that drives a pair of resistive odour sensors one polymer sensor is active while the other is passivated. The output of the ratio of the resistances is amplified rather than the absolute resistance of just one sensor. This removes at the input stage of the amplifier any common mode signals, such as temperature drift. 

---