Experimental study of physicochemical changes in water by iterative contact with hydrophilic polymers: A comparison between Cellulose and Nafion

Water kept in contact with cellulose has not been a “juicy” research topic until now. This is surprising because cellulose is a major component of the cell walls in green plants. It is also a common material used in many artificial systems, e.g., filters. In this work, we review some of our experimental results and show that iteratively bringing cellulose (cotton wool) in contact with pure water endows the water with some unforeseen properties. For example, the liquid left over after removing the cellulose is optically active, i.e., mirror symmetry breaking was triggered during temporary contact of bulk water with a natural polymer. (Here and in the following, by “mirror” symmetry we actually mean “chiral” symmetry). Moreover, this leftover liquid fluoresces after irradiation with ultraviolet light. These properties are neither attributable to impurities released by the inert polymer nor to organic- or bio-contaminants, as our state-of-the-art analytical techniques show. These techniques include gel electrophoresis, Matrix-Assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) and Gas Chromatography both coupled with Mass Spectrometry. Instead, the properties are attributable to stabilization of interfacial water adjacent to hydrophilic membranes. Our findings have implications for processes in water flowing adjacent to cellulose, in particular enantioselective processes. Such processes play critical roles in many bio-systems and technologies. Thus, our study indicates that water iteratively brought in contact with cellulose merits intensive research.