How to Make Cellulose Hate Water – “Change it, cover it, confuse it, or accept it as it is”
Keywords:Wettability, Nonpolar, Hydrophilic, Hydrogen bonding, Crystal faces of cellulose
In many of its current and potential applications, technologists treat the surface of cellulose to render it more hydrophobic. By use of a variety of hydrophobic sizing treatment strategies, the bulk cellulose phase becomes covered up with a layer having lower polarity and less inclination to interact with water. Often, the goal is to use a relatively low amount of additive to cover up or change just the surface of the cellulosic material, while still benefiting from the strength, recyclability, relatively low cost, and other favorable features of the bio-based material. But what often gets forgotten is that the hydrophilic nature of pure cellulose is not very high, and there are ways to manipulate such characteristics without reacting the material or covering it up. Sometimes reacting the cellulose with hydrophobic substituent groups appears to make it more water-loving. So, when thinking broadly of processing options for new applications, there are several contrasting approaches to consider.