Abstract
Triblock copolymers consisting of Polyethylene glycol (PEG), Potassium 3-sulfopropyl methacrylate (PSMPA) and Poly(N-isopropylacrylamide) (PNIPAAM) have a phase transition, which can be studied using techniques such as turbidimetry and densitometry. The changes in phase transition are detected by increasing the temperature. The length of the PNIPAAM-block and salinity of the solutions have the same effect on the cloud point of the copolymer. Hyperbranched poly(ethylene)imines (PEIs) with various substitution of maltose on the surfaces are also characterized with respect to pH of the solutions and the concentration of the PEI. The sizes are in a range of 10-15 nm, independent of pH and concentration. The structures of the PEIs can be characterized as fluffy spheres. Further, stability and solubility of all-trans-retinol by the PEIs is assessed. Complexion did not affect the stability of retinol. The solubilization of retinol is increased by PEI-Mal-A, which is the PEI with the densest shell of maltose. However, the process is very slow in aqueous media.