Polyelectrolyte properties of cellulose

Cellulose is not soluble in any inexpensive and safe solvent, limiting its applicability in many situations. Yet, it is the most abundant and sustainable polymer on Earth. Cellulose macromolecules are often described as electroneutral, and their insolubility is frequently ascribed to strong hydrogen bonds, but it is now understood as the result of concurrent electrostatic, hydrogen bonding, and hydrophobic interactions. Bjorn Lindman introduced the latter based on the unique structural features of cellulose chains, which received only partial acceptance. Cellulose is a very weak acid with pKa equal to or greater than 12, explaining its solubility in alkaline solutions.

Cellulose solutions have unique adsorption, agglutinating and dispersant properties. They exfoliate graphite down to nanographite and multilayer graphenes that lead to interesting applications as functional paints and coatings used as: flame retardants, conductive materials, sensors, electrodes, and inhibitors of colonization of boat hulls and marine structures by various species. Polished surfaces reduce boat drag, producing substantial fuel savings.

The paints are aggressive due to sodium hydroxide, but the dry coatings are not, since the hydroxide is neutralized by atmospheric CO₂, forming sodium carbonate and bicarbonate. This platform is sustainable: it is made from renewable or abundant raw materials, and it is easily circularized.