Switching surface properties of substrates by coating with a cellulose nanofiber having a high adsorbability

Abstract

It was reported in our previous paper that the dispersion containing single cellulose nanofibers (= nanocellulose) was prepared from microbial cellulose pellicle using aqueous counter collision (ACC) method [1]. In this study, the nanocellulose has been investigated from the view point of a coating agent. Thus, various substrates such as a filter paper, polyethylene (PE), polyethylene terephthalate (PET), and polypropylene (PP) films or sheets were coated with the nanocellulose, respectively. As a result for a hydrophilic substrate, both water and oil resistances on the surface of the nanofiber-coated filter paper were improved. On the other hand, coating with the same nanocellulose transformed the hydrophobic surface of PE, PET and PP sheets into the hydrophilic. This indicated that the nanocellulose, which was originated from microbial cellulose pellicle, had an effect switching surface properties depending on characteristics of substrates, differing from the wood cellulose nanofibers. Namely, the nanocellulose was preferably coated and adsorbed with the surface of substrates, whereas wood cellulose nanofibers prepared using ACC method and the homogenized pellicle did not accomplish such a behavior. Moreover, the dyeing as well as the improvement in water and oil resistances was performed simultaneously by coating using a mixture of nanocellulose with a dyeing agent.