We describe the LCST-type phase behavior of poly(ethylene oxide) (PEO) dissolved in imidazolium-based tetrafluoroborate ionic liquids (ILs). Phase diagrams were determined by a combination of small-angle neutron scattering (SANS) and cloud point (CP) measurements. Unlike typical LCST phase diagrams of polymer solutions, the PEO/IL phase diagram is either roughly symmetric with a critical composition near 50% polymer or asymmetric with a critical composition shifted to an even higher concentration of PEO. As the molecular weight decreases from 20 500 to 4200 g/mol, the critical temperature (Tc) increases slightly (∼10 °C). However, a larger increase in Tc (27 °C) was observed as the molecular weight decreases from 4200 to 2100 g/mol, likely due to the increasing importance of hydrogen bonds between the −OH end groups of PEO and the fluorine atoms of the anions. This inference is supported by the strong dependence of the phase diagram on the identity of the PEO end groups (hydroxy vs methoxy). Furthermore, ...
Hau-Nan Lee; Nakisha Newell; Zhifeng Bai; Timothy P. Lodge
The two enantiomers of 2-(2-hydroxybiphenyl-4-yl)propanoic acid ((S)- and (R)-BPOH) have been selected as probes for human serum albumin (HSA). Photophysical characterization in the absence of protein led to emission maxima, singlet energies, quantum yields, and fluorescence lifetime values ... more
The photodissociation of H2O in its B band is a prototype for nonadiabatic reaction dynamics. In addition to dissociation via the adiabatic pathway to the OH(Ã2Σ+) + H fragments, it also produces the OH(X̃2Π) + H fragments through two nonadiabatic pathways: the B̃ → X̃ transition via two co ... more
Due to the widespread occurrence in the environment and potential risk toward organisms of fluoroquinolones (FQs), it is of importance to develop high efficient methods for assessing their occurrence and environmental risk. A monoclonal antibody (Mab) with broad cross-reactivity to FQs was ... more
Rohm and Haas Powder Coatings is delighted to announce that its Reading, Pennsylvania, facility is the first site in the world to receive the RCMS® Site Certification awarded by the American Chemical Council (ACC).
When Raj Gupta, Chairman and CEO of Rohm and Haas Company, became Chairman ... more