A comparative investigation of the aggregation in aqueous solution of a poly(ethylene oxide)-poly(propylene oxide)poly(ethylene oxide) block copolymer (PEO-PPO-PPO) (Pluronic F127) with a polydimethylsiloxane-graft-polyether (PDMS-PEO) has been done. The spectroscopic parameters obtained from absorption spectra of the 4,4,5,5tetramethylimidazoline-1-oxyl-3-oxide-2-undecyl (TEMIDO-undecyl) and f...

Previous studies have examined different strategies for siRNA delivery with varying degrees of success. These include use of viral vectors, cationic liposomes, and polymers. Several copolymers were designed and synthesized based on blocks of poly(ethylene glycol) PEG, poly(propylene glycol) PPG, and poly(l-lysine). These were designated as P1, P2, and P3. We studied the copolymer self-assembly,...

Water vapor sorption in films consisting of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) amphiphilic block copolymers has been measured gravimetrically at air relative humidity in the range 38–94% at 248C. The water sorption isotherm was obtained and compared to data for water vapor desorption (drying) for the same system. The kinetics of water vapor sorption we...

Molecular diffusion of triblock copolymers poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) in water was studied with the help of Pulsed Field Gradient NMR in the broad range of polymer weight fractions from 0.09 to 0.8. Owing to amphiphilic nature of the molecules, these block copolymers exhibit rich self-organization properties when mixed with water. In particular, at ambient t...

This study investigates the effect of alcohols on the solution and adsorption properties of symmetric triblock nonionic copolymers comprising blocks of ethylene oxide (EO) and propylene oxide (PO) (EO(37)PO(56)EO(37)). The cloud point, surface tension, critical micelle concentration (CMC), and maximum packing at the air-water interface are determined, and the latter is compared to the amount of...

The phase behavior of two types of poly(ethylene oxide)/poly(propylene oxide) (PEO/PPO) copolymers in aqueous solutions was studied by light scattering, viscometry, and infrared spectroscopy. Both the reverse poloxamer (Pluronic 10R5) and the star type poloxamine (Tetronic 90R4) have practically the same PEO/PPO ratio with their hydrophobic blocks (PPO) located in the outer part. The temperatur...

Pluronics are triblock copolymers of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide). Pluronic P85 forms a rich phase behavior when dissolved in water. Unimers are observed at low temperature while micelles form at higher temperatures. Spherical, cylindrical, and lamellar micelles are observed sequentially upon heating. The effect of hydrostatic pressure on the phase boundaries ...

The advancement of gene-based therapeutics to the clinic is limited by the ability to deliver physiologically relevant doses of nucleic acids to target tissues safely and effectively. Over the last couple of decades, researchers have successfully employed polymer and lipid based nanoassemblies to deliver nucleic acids for the treatment of a variety of diseases. Results of phase I/II clinical ...

Polydimethylsiloxane (PDMS) oligomers with ranging from 900 to 7000 g/mol and which were α,ω-aminopropyl, α,ω-N-methylaminopropyl and α,ω-hydroxyhexyl terminated were obtained from Th. Goldschmidt AG in Essen, Germany. The of amine-terminated oligomers were determined by the titration of the end groups with hydrochloric acid. The of hydroxyhexyl terminated PDMS oligomers were det...

The adsorption thermodynamics of copolymers, based on ethylene oxide (EO) and propylene oxide (PO) units, at the laponite (RD) clay/liquid interface was determined at 298 K. The copolymer nature was tuned at molecular level by changing the hydrophilicity, the architecture and the molecular weight (Mw) keeping constant the EO/PO ratio. Polyethylene (PEGs) and polypropylene (PPGs) glycols with va...