Steady-shear rheology properties of polydimethylsiloxane (PDMS) colloids as a new contrast agent for nuclear magnetic resonance imaging



This work investigated the toxicity, the nuclear magnetic resonance (NMR) spectra, the NMR imaging, and the steady-rheology properties concerning polydimethylsiloxane (PDMS) colloids. These experiments illustrate low toxicity, strong NMR signal intensity, as well as clear images, and render the colloids the potential application as contrast agent for gastrointestinal NMR imaging. The steady-shear rheology data are fitted very well by the model τ = τ0 + AÝm. According to the theory of Princen and Kiss, 12 we found the yield stresses (τ0) of the colloids are proportional to φ1/3/D in 0.72 ≦ φ ≦ 0.81. Based on the model and the definition of the capillary number Ca = τ/(σ/R), a linear relationship between log(D) and m was discovered if the assumptions that 2Ca σ/A and Ýeff are constants are satisfied. We also proved these assumptions are rational in the investigated range 0.62 ≦ φ ≦ 0.81. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1888–1896, 2002