Interplay of electrolyte concentration and molecular weight of polyDADMAC on cellulose surface adsorption

Cationic polyelectrolytes (PEs) are commonly used additives in manufacturing of cellulose based products such as regenerated fibers and paper to tailor their product properties. Here we are studying the adsorption of poly(diallyldimethylammonium chloride), PD, on cellulose, using in situ surface plasmon resonance spectroscopy (SPR) measurements. We employ model surfaces from regenerated cellulose xanthate (CX) and trimethylsilyl cellulose (TMSC), mimicking industrially relevant regenerated cellulose substrates. The effects of the PDs molecular weight were strongly depending on the ionic strength and type of electrolyte (NaCl vs CaCl2). Without electrolytes, the adsorption was monolayer-type, i.e. independent of molecular weight. At moderate ionic strength, adsorption increased due to more pronounced PE coiling, while at high ionic strength electrostatic shielding strongly reduced adsorption of PDs. Results exhibited pronounced differences for the chosen substrates (cellulose regenerated from xanthate (CXreg) vs. regenerated from trimethylsilyl cellulose, TMSCreg). Consistently higher adsorbed amounts of the PD were determined on CXreg surfaces compared TMSC. This can be attributed to a more negative zeta potential, a higher AFM roughness and a higher degree of swelling (investigated by QCM-D) of the CXreg substrates.

Publication year: 2023
Authors: Sampl C. a,b, Schaubeder J. a, Hirn U. a,b, Spirk S. a,b

a – Institute of Bioproducts and Paper Technology, Graz University of Technology, Inffeldgasse 23, 8010 Graz, Austria
b – Christian Doppler Laboratory for Fiber Swelling and Paper Performance, Graz University of Technology, Inffeldgasse 23, 8010 Graz, Austria

Published in: International Journal of Biological Macromolecules, 2023, Vol. 239, p. 124286
DOI: 10.1016/j.ijbiomac.2023


210A VASA cellulose layer characterization


Other publications