Affiliation:
1. School of Material Science and Engineering, Shenyang University of Technology , Shenyang 110870 , China
2. Department of Environmental and Biological Engineering, Shenyang Institute of Science and Technology , Shenyang 110167 , China
Abstract
Abstract
Capacitive deionization electrode prepared by coating was commonly investigated, with polymer solution as binder and active particles as adsorbent. In the coating process, microstructure constituted by the two components was damaged by shear, then rebuilt when shear was removed. The microstructure strongly influenced the surface structure of the coated electrodes, further to performance and cycle life. The discussion of the interaction between the components in the coating process facilitates the identification of structural mechanisms. Rheology bridged the flow regimes in macroscale and interaction in microscale, through which the interaction between the polymer and particles can be investigated in a macroscopic phenomenon. In this study, hydrophilic polymer, poly(vinyl alcohol) (PVA), and poly(ethylene oxide) (PEO) were used as binders to prepare the suspension for coating. The influence of polymer molecular structure to interaction and microstructure was investigated by rheology. Results showed that the flexibility of polymer determined the adsorption morphology, leading to different flocculation structures. For rigid PVA, a 3d-crosslinked network was formed, giving a tough coating. While for flexible PEO, encapsulation structure was formed, leading to a brittle coating. A model based on bridging flocculation was evaluated to describe the formation and destruction of the flocculation structure. And a rheological method for binder selection and coating operation was proposed.