Although much is known about homogenous crystallization in liquid systems, little fundamental information is available on the impact of the surface chemistry and nano-scale topology of heterogeneous surface crystallization, kinetics of surface crystallization and morphology of the formed crystals. Similarly, while there is vast literature on the adsorption of organics onto polymeric resins and membranes, the kinetics of surface sorption and observation of surface deformation (or swelling of surface chains) at the nano-scale level are lacking.

 The present study will focus on a systematic investigation of surface chemistry and morphology factors that affect surface crystallization of inorganic salts with some comparison with sorption of organics as an added measure of surface characterization. In addition the study will also explore the potential effect of dissolved organics on mineral salt crystallization.

Various surrogate surfaces will be prepared by graft polymerization techniques developed in our laboratory to evaluate the impact of surface topology and chemistry on surface crystallization (crystallization kinetics, the type and structure of formed crystals, adhesion of crystals to the surface). Surfaces will be characterized by atomic force microscopy (AFM), contact angle measurements, XPS and FTIR.  Surface crystallization studies will be conducted using specialized quartz crystal microbalance to enable direct determination of surface crystallization kinetics.

Reference:

• Shih, Wen-Yi,  Anditya Rahardianto, Ron-Wai Lee, and Yoram Cohen "Morphometric Characterization of Calcium Sulfate Dihydrate (Gypsum) Scale on Reverse Osmosis Membranes," Journal of Membrane Science, submitted (2004).

Development of Gypsum crystals along a Reverse Osmosis membrane