Poly molecular parameters

Table 2 Molecular parameters of the thermally precipitating and non-precipitating fractions of poly(NVCl-co-NVIAz) in aqueous solutions at 20 and 50 °C (the data from [42])... 

As the final products— polystyrene-Zi-poly(vinylperfluorooctanoic ester)— form micelles in tetrahydrofuran (THF) as well as in DMF, there are not direct GPC data to characterize molecular parameter. For this reason, we employed esterification of the hydroxylated block copolymers with benzoylchloride as a model reaction to obtain a comparable product with molecular solubility that can easily be characterized by DMF-GPC. The GPC data from PSB-II—our largest and therefore most sensitive block copolymer—are summarized in Table 10.2. Results for all the other polymers are similar. 

Materials. GMC and PCLS were synthesized by free radical solution polymerization initiated by benzoyl peroxide as described previously (5,6). Nearly mono and polydisperse polystyrenes were obtained from Pressure Chemical Co. and the National Bureau of Standards respectively. Molecular weight and polydispersity were determined by gel permeation chromatography (GPC) using a Water Model 244 GPC, equipped with a set (102-106 A) of —Styragel columns using THF as the elution solvent. The molecular parameters of the above three polymers are listed in Table I. The copolymer, poly(GMA-co-3-CLS), contained 53.5 mole % 3-CLS and 46.5 mole % GMA, as determined by chlorine elemental analysis. The structure of the copolymer is shown in Figure 1. 

Table I. Effect of Variation in Viscosity on Molecular Parameters Calculated from Polarization of Fluorescence Measurements in Aqueous Glycerol Solutions of Poly GluMLys 7 (No. 3) (48)f...

L.F. Thompson, J.P. Balantyne, andE.D. Feit, Molecular parameters and lithographic performance of poly(glycidyl methacrylate co ethyl acrylate) A negative electron resist, J. Vac. Sci. Technol. 12, 1280 (1975). 

Lbonard, C., Halary, J. L., Moimeiie, L., (1988), Crystallization of poly(vinylidene fluoride)-poly(methyl methacrylate) blends analysis of the molecular parameters controlling the nature of p>oly(vinylidene fluoride) crystalline phase. Macromolecules, Vol 21, No. 10, (October 1998) pp. 2988-2994, ISSN 0024-9297. 

TABLE 4. Molecular Parameters of Poly(METMA/MES) in Various Electrolytes... 

Y(CF3C02)3/Al(0-j-Bu)3 also leads to the formation of poly( -CL), poly(DL-LA) (53), and block copolymers (54) with a rather good control of the molecular parameters. The mechanism remains however an open question. 

In the case of polyaniline samples the increase in reflection coefficient is correlated to the increase in static conductivity. In the case of poly(alk)dthiophene)s, we found out that control of molecular structure permits to increase conductivity at molecular level but is not sufficient to insure high level of static conductivity of the material. Moreover no correlation was found between static conductivity and reflection coefficient in the infirared domain. In fiict static conductivity is not only influenced by molecular parameters but also by structural parameters at supramolecular scale. The effect of structural parameters on microwave properties of low conductivity sanoples ( 10 -5 S.cm ) has already heea reported (2). By increasing the conductivity we have shown that microwave properties for Ugh conductivity sanq>les will only depend on the static conductivity and thickness of samples in term of absoibed, reflected and transmitted power for a givoi fi-equency. Differoit materials such as polypyrrole, polyaniline or indium tin oxide deposits were found to give same results en the surface resistance of the deposits was k t the same. 

The preparation procedure of narrowly distributed Seesaw-type macromonomer triblock copolymers, poly(tert-butyl acrylate)-polystyrene-poly(terr-butyl acrylate) (PtBA-PS-PtBA), with one alkyne group in the center of the PS block and one azide group at the end of each PtBA block is similar to that of macromonomer polystyrene homopolymers. The schematic synthesis of PtBA-PS-PtBA triblock copolymer is shown in Fig. 3.8. The corresponding DP values were calculated from area ratio of corresponding peaks in NMR spectrum, as shown in Fig. 3.9, and the molecular parameters of our obtained triblock copolymers macromonomer PiBA-PS-PtBA with different St and tBA molar contents and molar masses are summarized in Table 3.2. 

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