Thermodynamics of the partitioning of poly(propylene oxide) between aqueous and chlorinated organic phases compared to poly(ethylene oxide) and other hydrophilic polymers

Abstract

Thermodynamic functions associated with the partitioning of poly(propylene oxide), PPO, between aqueous and organic (chloroform, dichloromethane, and chlorobenzene) phases were determined and analyzed in comparison with those for the partitioning of poly(ethylene oxide), PEO, and poly(vinyl pyrrolidone), PVP. Amounts of water accompanying the partitioning of PPO to the organic phases were also measured. These results reveal that PPO partitioning is controlled by hydrophobic effects (entropic contribution), which was confirmed by the release of a significant amount of water molecules following the partitioning. Hydrophilic polymers like PVP and polyacrylamide, on the other hand, remain almost quantitatively in the aqueous phase. PEO remains a unique example of a polymer displaying high affinity for water, but that can be extracted to certain organic solvents (which should display hydrogen bond donating capacity).

Interfacial properties of Pluronics and the interactions between Pluronics and cholesterol/DPPC mixed monolayers

“…The interaction between PEO polymers and the organic solvent was suggested to occur through hydrogen bond-donating capability of the solvent. Similarly, Anselmo et al [34] proposed that PEO, though undoubtedly hydrophilic, may be extracted to organic solvents that are capable of interacting as hydrogen bond donors. Therefore, we suggest that the PEO-related stronger interaction forces might be also due to the hydrogen bonding effects between the ether oxygen of PEO chains and the 3β-hydroxy group of cholesterol.…”

Surface-Bound Proteins with Preserved Functionality

“…Increase in R DM above 0.05 causes a rapid increase in C GFP with a rate, C GFP / R DM , of about two molecules per nm 2 . For R DM exceeding 0.1, C GFP plateaus at maximum value of about 0.13 molecules per nm 2 , which corresponds to an average surface area of about eight nm 2 for a single GFP molecule.…”

“…Covalent attachment of amine derivatives of PEGs (MW~2 kDa) to freshly deprotected aldehyde surfaces, via reductive amination, yielded polymer layers containing about three PEG molecules per nm 2 . Using mixtures of monoamine and a,x-diamine polymers, H 2 N-PEG-O-CH 3 and H 2 N-PEG-NH 2 , respectively, allowed us to prepare PEG layers with free amines on their surfaces (Scheme 1, iii).…”

“…Other polyethers, such as polymethylene oxide (i.e., polyformaldehyde) and polypropylene oxide, for example, with higher or lower relative content of ether oxygens, respectively, are not water soluble. 2,31,73 Covalent attachment of polymers to silica-based surfaces can be performed in a single-step process (i.e., direct covalent attachment of the polymer to the substrate), 84 or via multiple-step procedures. 17 While the single-step approaches for derivatization of surfaces are expedient, they are limited by the availability of polymer derivatives containing functional groups, such as alkoxysilyls, necessary for anchoring the macromolecules to the surfaces.…”

Interaction of poloxamine block copolymers with lipid membranes: Role of copolymer structure and membrane cholesterol content

“…This correlates well with the decreased cell binding of Pluronics in erythrocytes compared to tumor cells [25]. On the other hand, hydrogen bonding can occur between the 3␤-hydroxy group of cholesterol (Brønsted acid) and the ether oxygens of PEO block (Lewis base) [38,39].…”