Polyelectrolyte complex containing antimicrobial guanidine-based polymer and its adsorption on cellulose fibers

Polyelectrolyte (PE) complexes (PECs) are formed by the electronic interaction between cationic and anionic PEs, and a number of factors influence the forming pattern and characteristic of the PECs. In this work, a guanidine-based polymer with high cationic charge density (CD) and low molecular weight (MW) was applied for interacting with anionic carboxymethylcellulose (CMC) with low CD and high MW. To reveal the self-assembly pattern of the PEC, the turbidity of PEC and layer-by-layer (LBL) film, along with its adsorption on cellulose fibers, was characterized. The antimicrobial activity of the handsheet containing the PEC was also investigated. The charge ratio of anionic PE to cationic PE was found to be critical to the PEC stability. The roughness of the LBL film was increased and then decreased with more bilayers assembled. The isothermal adsorption indicated that the amount of adsorbed cationic PE on cellulose fibers was increased significantly by interacting with anionic CMC. The inhibition of the cationic PE on bacterial growth was not impaired by the formation of the complex. The CMC with high MW in the complex could maintain or even improve the antimicrobial efficiency of the guanidine-based polymer in handsheet.