Rheo-SAS: feasibility to characterize concentrated colloidal particle suspensions for their processing

Abstract This chapter summarizes the series of different developments and investigations on in situ coupling of rheology with small-angle scattering (rheo-SAS) measurements of colloidal particle suspensions. This coupling allows us to directly correlate microscopic particle–particle interaction with macroscopic suspension behavior under different physical and chemical environments. This summary provides a better understanding of the basic phenomena/theory associated, historical development and current status of rheo-SAS, and also discusses its applicability and limitations/variations to different types of concentrated particle suspensions. Two different rheo-SAS methodologies, i.e., rheo-SAXS (small-angle X-ray scattering) and rheo-SANS (small-angle neutron scattering), are introduced and discussed in terms of their similarities/differences as well as strength/uniqueness. In this article, aqueous suspensions composed of colloidal particles, including metal oxide particles and their composites with clay particles and polymers, are introduced as examples. The research gaps are identified and specific future perspectives are discussed to further enhance the use of this useful coupling, and its application toward the transition from the evaluation of simple particle suspension systems to more complex particle suspension systems that fit more with the interest and needs of particle processing industries.