Surface tension of polyoxyethylene glycol solutions

Abstract

The surface tension of polyoxyethylene glycol in water leads to a value for the area per molecule which shows that the polymer molecules lie approximately flat in the surface. Molecular weight determinations by end‐group analysis and freezing‐point depression are compared with values of the intrinsic viscosity and limiting area per molecule.

The Physical Environment of Chloroplasts as Related to their Morphology and Activity in Vitro

“…Viscosity, of course, will be of importance in experiments involving diffusion and sedimentation rates. The extent of surface tension lowering is not large, and the data of Couper and Eley (11) if extrapolated to the high concentrations used here, indicate about the same surface tension for all (61-63 dynes/cm). Finally, it seems possible that the change in proportions of end groups with molecular weight might change some property such as dielectric constant.…”

“…The polyethylene glycols are linear polymers of the formula HOCH2(CH2OCH2)nCH2OH, water soluble solids (molecular weight at least 1000) and liquids. There is some uncertainty as to the molecular weight of the higher Carbowaxes, as that computed from the end group assay (roughly equivalent to the number in the manufacturer's designation) is considerably higher than published values calculated from freezing point depressions (11,35). The preparations available and used here are designated Carbowaxes 1000, 1540, 4000, 6000 (while Carbowax 1500 is a mixture of 1540 and a liquid polymer) and Polyethylene Glycol 400.…”

“…Such a comparison using Griffithsia is shown in table IV. The comparison is shown at the same weight concentration, since the colligative properties do not follow van't Hoff's law (11,39), and precise and reliable comparisons of these properties were not available. A point of reference is available, however, as Griffithsia cells were found to be about isotonic with a solution of 4 gm of Carbowax 4000 in 10 ml of 0.1 M phosphate buffer (pH 6.8).…”

Effect of water stress on carbon isotope discrimination and Rubisco activity in bread and durum wheat genotypes

“…at 35 days after transplanting) using different concentration (10, 20 and 30 %) of PEG-6000 and physiological and biochemical observations were taken at 24, 48 and 72 hours after PEG treatment. PEG was used to induce water stress because it is an inert polymer, with a non-ionic and virtually impermeable long chain (Couper and Eley 1984) which helps to maintain uniform water potential during the whole experimental period.…”

Changes in the proteome of pea (Pisum sativum L.) seeds germinating under optimal and osmotic stress conditions and subjected to post-stress recovery

“…Therefore, good hydration of the protoplasm determines the right course of all cellular processes. Among the most significant environmental factors which affect the hydration of tissue and, consequently, the course of cellular processes is osmotic stress, which can be studied in a laboratory through the application of polyethylene glycol (PEG) (Couper and Eley 1984). Osmotic stresses within -0.2 and -0.5 MPa often occur in soils across Europe.…”