期刊
JOURNAL OF CHEMICAL PHYSICS
卷 130, 期 13, 页码 -出版社
AMER INST PHYSICS
DOI: 10.1063/1.3103889
关键词
colloids; elastic moduli; light scattering; liquid structure; mixtures; polymer gels; rheology; viscoelasticity
资金
- Deutsche Forschungsgemeinschaft (DFG) [SFB-TR6P]
- EU [03E.566]
- Engineering and Physical Sciences Research Council [EP/E030173/1] Funding Source: researchfish
- EPSRC [EP/E030173/1] Funding Source: UKRI
We investigate the structural, dynamical, and viscoelastic properties of colloid-polymer mixtures at intermediate colloid volume fraction and varying polymer concentrations, thereby tuning the attractive interactions. Within the examined range of polymer concentrations, the samples varied from fluids to gels. In the liquid phase, an increasing correlation length of the density fluctuations when approaching the gelation boundary was observed by static light scattering and microscopy, indicating clustering and formation of space-spanning networks. Simultaneously, the correlation function determined by dynamic light scattering decays completely, indicating the absence of dynamical arrest. Clustering and formation of transient networks when approaching the gelation boundary is supported by significant changes in the viscoelastic properties of the samples. Upon increasing the polymer concentration beyond the gelation boundary, the rheological properties changed qualitatively again, now they are consistent with the formation of colloidal gels. Our experimental results, namely, the location of the gelation boundary as well as the elastic (storage) and viscous (loss) moduli, are compared to different theoretical models. These include consideration of the escape time as well as predictions for the viscoelastic moduli based on scaling relations and mode coupling theories.
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