Insun Park

Novel Thermoreversible Gelation of Biodegradable PLGA-block-PEO-block-PLGA Triblock Copolymers in Aqueous Solution

The BAB-type triblock copolymers composed of a central poly(ethyelene oxide) (PEO, M nPEO = 1000) block and two poly[(D,L-lactic acid)-co-(glycolic acid)] end blocks with molecular weights between 900 and 1 600 exhibited an intersting phase transition behavior. The copolymer aqueous solution can form micelles with PLGA loops in the core and a PEO shell and groups of micelles because of bridging between micelles caused by the PLGA blocks with raising temperature. A possible micellar gelation mechanism was suggested.

Electron density map using multiple scattering in grazing-incidence small-angle X-ray scattering

The electron density map of a block copolymer thin film having the hexagonally perforated layer (HPL) structure was directly obtained from the measured grazing-incidence small-angle X-ray scattering (GISAXS) pattern, exploiting the multiple-scattering phenomena present in GISAXS. It is shown that GISAXS is in principle equivalent to three-beam diffraction, which has been used to extract phases of diffraction peaks. In addition, X-ray reflectivity analysis has been performed which, when combined with the GISAXS results, provides full details of the HPL structure.