title: A phenomenological one-parameter equation of state for osmotic pressures of PEG and other neutral flexible polymers in good solvents.
abstract: We present a phenomenological one-parameter scaling equation of state that accurately represents osmotic pressures of neutral flexible polymers in good solvents from the dilute through the semidilute regime. The equation comprises a sum of scaled van't Hoff and des Cloizeaux terms including a fitted parameter alpha, the "crossover index", which encapsulates all chemical specificity and determines the relevant prefactors. Strikingly different values of alpha are found for the two very different systems poly(ethyleneglycol)/water (PEG) and poly(alpha-methylstyrene)/toluene (PAMS). Alpha-dependent rescaling collapses both data sets to a simple one-parameter scaling function. The fact that the anomalous system PEG/water and the canonical system PAMS/toluene can both be described by the same equation of state attests to the robustness of the polymer-scaling concepts introduced by de Gennes.
authors.affiliation: Laboratory of Physical and Structural Biology, PPB, NICHD, NIH, Bethesda, Maryland 20892-0924, USA. jcohen@pacific.edu
authors.forename: J A
authors.initials: JA
authors.lastname: Cohen
authors.forename: R
authors.initials: R
authors.lastname: Podgornik
authors.forename: P L
authors.initials: PL
authors.lastname: Hansen
authors.forename: V A
authors.initials: VA
authors.lastname: Parsegian
mesh_terms: D009997:Osmotic Pressure; D011092:Polyethylene Glycols / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013343:Styrenes / Q000737:chemistry*; D014050:Toluene / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D012997:Solvents; D013343:Styrenes; D014867:Water; C027142:vinyltoluene; D014050:Toluene; D011092:Polyethylene Glycols