The effect of surfactant concentration on the complex structures of the thermosensitive poly(N-isopropylacrylamide) (PNIPAM) with sodium n-dodecyl sulfate (SDS) in dilute aqueous solutions and below the lower critical solution temperature were investigated using viscometry, two-dimensional nuclear Overhauser effect spectroscopy (2D NOESY), and pulsed-field gradient diffusion nuclear magnetic resonance (NMR). The interactions of PNIPAM and SDS were found to exhibit strong dependences on the SDS concentration. The amount of polymer-bound and free SDS at various SDS concentrations was calculated from the diffusion coefficients of SDS. At SDS concentrations below the critical aggregation concentration (CAC) of around 0.86 mM, the interaction between PNIPAM and SDS was very minimal, resulting in almost no change in the intrinsic viscosity and hydrodynamic size of the polymer. At SDS concentrations above 0.86 mM but below 7.0 mM, the intrinsic viscosity of the polymer as well as the amount of polymer-bound SDS ...
Jianqiang Chen; Hongjuan Xue; Yefeng Yao; Hu Yang; Aimin Li; Min Xu; Qun Chen; Rongshi Cheng
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