Convex solubility parameters for polymers

Solubility parameters are certain measurable quantities that are observed to influence the ability of a solvent to fully dissolve a polymer. Current theory partitions the intermolecular forces between dispersion, polar, and hydrogen bonding interactions, thereby generating a three‐dimensional solubility parameter space. The Hansen solubility parameters of a polymer are taken to be the center of a sphere obtained from the best fit of the coordinates of good solvents in the parameter space. Investigations of several polymers (lignin, polyethersulfone, and bitumen) show that the convex hull of all known good solvents in the three‐dimensional parameter space also gives a meaningful interpretation of the solubility region. Several methods for computing the convex solubility parameters of a polymer from the convex solubility region are described. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1089–1097     

The solubility product of cadmium sulphide

The solubility product of cadmium sulphide has been measured in three acidic media by precipitation and dissolution techniques. The values of log K(s0) after correction for complex formation are -27.3 +/- 0.6 in all the media examined. An X-ray and microscopic examination of the precipitates shows an increase in crystallinity on aging, although Ostwald ripening was not observed.     

The Ostwald coefficient of gas solubility

The Ostwald coefficient which is used for expressing gas solubilities is discussed from an historical perspective. Then four different Ostwald coefficients are defined and their interrelationships and limitations discussed.     

The solubility parameters of metal acetylacetonates

Solubility parameters for Be(acac)₂ and Th(acac)₄ calculated from viscosity measurements on dilute solutions in benzene at 25.0°C have been compared with data for tris-acetylacetonates of Al, Cr, Mn, Fe and Co. In non-polar solvents the value does not vary much with the nature of the metal (average δ₂ = 9.4 ± 0.4) nor do the molar volumes, which can be calculated from V_m = 90.5n ± 5%.     

The concept of fractional parentage for arbitrary molecular point groups

The method of fractional parentage is extended to the general case of mixed configurations in arbitrary nonsimply reducible groups, G ? SO(3). Particular attention is devoted to the calculation of coefficients of fractional parentage (CFP) and expressions are provided for the matrix elements of F and G type operators between N electron functions.     

Automated apparatus for gas solubility measurements

An automated apparatus based on the Ben-Naim–Baer and Tominaga et al. designs [A. Ben-Naim, S. Baer, Trans. Faraday Soc. 59 (1963) 2735–2738; T. Tominaga, R. Battino, H.K. Gorowara, R.D. Dixon, J. Chem. Eng. Data 31 (1986) 175–180] has been implemented for measurements of gas solubilities in liquids under atmospheric pressure and room temperatures. The uncertainty in the measurement of gas solubilities was estimated from the uncertainties in the directly measured quantities using the error propagation law. The accuracy of the experimental method was checked by measuring the solubility of carbon dioxide and nitrous oxide in water in the range T = (290 to 303) K, being found to be 0.6%. A precision of the same order of magnitude was achieved.     

The apparent solubility product of cerous fluoride

The apparent solubility product of cerous fluoride has been determined to be 8.1 ± 1.1·10^-16 und 1.1 ± 0.5·10^-15 by radiometric and conductometric methods respectively. Hydrolysis of cerous fluoride is thought to be negligble. The effect of hydrogen-ion concentration on the solubility of cerous fluoride has been measured in solutions of perchloric acid of varying acidity. The solubility Was found to decrease slightly as the pH decreased from 5 to 2 and then to increase rapidly as the pH further decreased from 2 to 0.     

The solubility loop of nicotine:water

The lower consolute temperature in the nicotine:water system arises from the equilibrium formation of a covalent hydrate, revealed by its unique circular dichroism.     

Molecular solubility and hansen solubility parameters for the analysis of phase separation in bulk heterojunctions

Although the fabrication procedures for bulk heterojunction (BHJ) solar cells are routinely optimized to accommodate new organic materials, the influence of solvent properties and cohesive forces on the film‐forming process and the self‐assembly of donor and acceptor molecules on the nanoscale are poorly understood. In this study, we measure the solubility of a variety of organic semiconductors in a range of solvents and calculate cohesive forces including dispersion forces, dipole interactions, and hydrogen bonding via Hansen Solubility Parameters (HSPs). HSPs were calculated by measuring the solubilities of various organic semiconductors in 27 solvents and the influence of solvent identity on film morphology of different BHJ mixtures was explored via atomic force microscopy (AFM). The possibility of correlations between HSPs and film morphology was considered; however, it is apparent that the HSP values alone do not play a critical role in determining the morphology of the films of conjugated polymers and molecules. This collection of solubility data constitutes the first of its type for organic semiconducting materials, and may act as a useful reference for the organic semiconductor community to aid in the understanding and selection of solvents for donor–acceptor BHJ mixtures. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

Solubility profiles of poly(ethylene glycol)/solvent systems, I: Qualitative comparison of solubility parameter approaches

Solubility of systems involving four different molecular weights of poly(ethylene glycol) (PEG) in tetrahydrofuran (THF), chloroform, dimethylsulfoxide (DMSO), methanol and water have been investigated by different algorithmic approaches as the mathematical application of the “like dissolves like” principle. In this study, the solubility parameters and their components for PEG and solvents have been evaluated by using of atomic group contribution methods; Small, van Krevelen-Hoftyzer (VKH), Hoy and Breitkreutz methods, respectively. Then their 2-dimensional graphs (Bagley, Henry and Hoernschemeyer diagrams) and 3-dimensional graph (Hansen diagram) have been drawn by creating the solubility profiles of the polymer in selected solvents. The dissolving capability of these solvents has been discussed. In addition the solubility parameters have been calculated by use of the van der Waals volume in the selected molecule or repeating unit of the polymer instead of the molar volume which is used in atomic group contribution methods (Askadskii approach). Surface tensions of the polymer and solvent systems have been calculated with this method and solubility criteria of PEG have been explained after a serial calculation steps. In addition, influence of molecular weight of PEG on solubility has been also analyzed. As a consequence of algorithmic calculations, THF has been determined as the best solvent whereas water is found to be the weakest solvent for polymer/solvent systems.     

A simple apparatus for data solubility determination

A relatively simple apparatus has been used to determine liquid hydrocarbon solubility in water. Liquid samples were taken from the liquid phase, through a silicon septum in the basis of the saturation cell, temporally until the final saturation. The equilibrium temperature was kept by a thermostatic bath. The liquid sample was analyzed using a gas chromatograph with a flame ionization detector (FID), and so, obtaining the solutions concentrations. For each solute, we found a different saturation time. However, it was observed that it occurred between 15 and 90 min. Measurements obtained for 1,2-dichroroethane, methylene chloride, toluene and pentane showed good agreement with literature values and allowed us to validate our equipment. The experimental data were correlated by using a two-parameter equation. The values obtained confirm the validity of equation tested.     

The solubility of struvite

The solubility of magnesium-ammonium-phosphate (struvite) has been studied employing radioisotope³²P as tracer. The amount of sample in solution is determined by measuring the Cherenkov radiation due to the fast -particles emitted from this radionuclide. The themodynamic solubility product is determined at various temperatures and compared with former results.     

The solubility of an hydroxyaluminosilicate

Hydroxyaluminosilicates (HAS) are critical secondary mineral phases in the biogeochemical cycle of aluminium. They are formed from the reaction of silicic acid (Si(OH)₄) with an aluminium hydroxide template and act as a geochemical control of the biological availability of Al. There are two main forms of HAS which we have called HAS_A and HAS_B and which of these will predominate will depend upon the Si(OH)₄ to Al ratio in any one environment. In all but the most heavily weathered environments or those undergoing a progressive acidification Si(OH)₄ will be present in significant excess to Al and HAS_B will be the dominant secondary mineral phase. We have tried to determine the solubility of HAS_B(s) so that its contribution to Al solubility control might be compared with other secondary minerals such as Al(OH)_3(gibbsite). In preliminary experiments, the dissolution of HAS_B(s) was found to be non-congruent with almost no Al being released during 18 months ageing. We then demonstrated that HAS_B(s) was significantly less soluble than Al(OH)_3(s) prepared under identical experimental conditions. We have used this information to describe a solubility expression for HAS_B(s) at a predefined quasi-equibrium and to calculate a solubility constant.

K^*Al₂Si₂O₅(OH)₄=[Al₂O⁴⁺][SiO₂]²[OH^-]⁴