**Abstract**

Cellulose is the most abundant natural compound in nature and the main component of the cell wall of plants. It is a linear polymer with a high degree of polymerization, responsible for most of the properties of wood. Colloidal phenomena are often used in various industrial production processes. Suspended cellulose, used worldwide in the paper and cellulose industries, with regard to stability, has a high tendency to aggregate and form clots. The different interactions between the dispersed phase and the dispersion phase are one of the critical points in the study of the behavior and stability of colloids. Cellulose is no different, as several studies seek to improve the colloidal stability of cellulose in aqueous media by observing the specific characteristics of the colloid, such as its geometry, mass and area/volume ratio, and the possible interactions between particles that make up the cellulose dispersion in order to understand and control colloidal stability. Therefore, the objective of this chapter is to define the main characteristics of colloids, to classify them, to present the main methods of preparation, to address important aspects about colloid stability and the colloidal stability of cellulose.

**Keywords:** colloids, suspension, cellulose, colloidal stability, cellulose fibers, lignocellulosic material

### **1. Introduction**

Colloids are heterogeneous mixtures of at least two distinct phases, with the material of one of the phases in a finely divided form (solid, liquid or gas), called dispersed phase, mixed with the continuous phase (solid, liquid or gas), called medium dispersion [1].

Understanding and controlling the stability of colloidal dispersions is essential for its satisfactory use. For both economic and environmental reasons, water is often required as a dispersing phase, even when the particles that need to be kept in suspension are hydrophobic, as is the case with cellulose [1].

Cellulose has been gaining importance in the industrial scenario due to the growing interest in sustainability and environmental protection, becoming a competitive material since it is renewable, abundant, low cost, non-petroleum and non-toxic [2].

Suspended cellulose has a tendency to aggregate. In this way, some strategies to avoid cellulose self-agglomeration in aqueous medium have been used in order to reduce the hydrophilic character of cellulose, avoiding the formation of additional hydrogen bonds between cellulose fibers [3].

Therefore, this chapter aims to contribute to the field of study of colloids and their characteristics, in addition to cellulose with regard to its characteristics and behavior of aqueous solutions of cellulose and alternatives sought to improve the colloidal stability of cellulose suspensions.
