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The attenuated total reflectance Fourier transform infrared dialysis technique is introduced for the time-resolved investigation of the binding processes of Ca2+ to polyacrylates dissolved in water. We observed transient formation of intermediates in water with various types of coordination of the carboxylate group to Ca2+ throughout the complexation steps. Time-resolved changes in the spectra were analyzed with principal component analysis, from which the spectral species were obtained as well as their formation kinetics. We propose a model for the mechanisms of Ca2+ coordination to polyacrylates. The polymer chain length plays an important role in Ca2+ binding.

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Poly(ethylene glycol) (PEG) was grafted to shortened single-walled carbon nanotubes (shSWNTs) obtained from original SWNTs after acid oxidative cutting and etching processes. PEGsh-SWNTs, prepared by treating the sh-SWNTs with SOCl 2 followed by amidation with PEGmonoamine (molecular weight = 2000), are moderately soluble in tetrahydrofuran, chlorinated hydrocarbons (ca. 1 mg/ml), sparingly soluble in water, acetone CH 3 OH and insoluble in non polar solvents such as toluene, hexanes or carbon disulfide. Non linear transmission measurements on solutions of PEG-sh-SWNTs in CHCl 3 showed a better optical limiting performance relative to that recorded for original SWNTs suspended in the same solvent.