Static Crossover of Critical Behavior in Polymer Blend Solutions: Scaling Analysis of the Ginzburg Number

• Published in: Macromolecules Vol. 28; no. 13; pp. 4433 - 4440
• Main Authors: Miyashita, Naoshi, Nose, Takuhei
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-06-1995
• Subjects: Applied sciences; Benzene; Exact sciences and technology; Light scattering; Organic polymers; Physicochemistry of polymers; Polymethyl methacrylates; Polystyrenes; Properties and characterization; Solution and gel properties; Thermal effects; Three dimensional; Critical property; Chemical solution; Ternary system; Concentration effect; Temperature effect; Methyl methacrylate polymer; Styrene polymer; Experimental study; Correlation length; Conformation; Chlorostyrene polymer
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma00117a012

By means of light scattering, the static critical behavior was investigated for symmetrical polymer blend solutions of polystyrene/poly(methyl methacrylate)/deuterated benzene and polystyrene/poly(2-chlorostyrene)/deuterated benzene with different polymeric indices N and polymer concentrations c. The temperature dependence of the isothermal susceptibility S sub(T) and the correlation length xi sub(t) near the stability limit showed the static crossover from the mean-field to the three-dimensional Ising behavior in all solutions. The Ginzburg number Gi super(BK) was evaluated with the aid of the crossover function of Belyakov and Kiselev. As c increases from the semidilute region to the bulk limit, the scaled Ginzburg number gi super(BK) identical with Gi super(BK)N decreased, with the power alpha of gi super(BK) proportional to c sub( alpha ) being -1.25 to -2 as expected by the theory based on the blob concept. The values of gi super(BK)(bare) evaluated by the bare interactions were smaller than experimental values.