Hydrogels and Nanohydrogels

Hydrogels and nanogels are exciting and promising materials for many applications due to their versatile features, such as interacting and absorbing a significant amount of water and other solvents, excellent mechanical properties, and adhesiveness. These materials are obtained based on the nature of the raw materials (natural or synthetic) and the synthesis route. There are many ways to synthesize hydrogels and nanogels; however, these routes can be classified as physical or chemical. Physical synthesis forms a reversible cross-linking. In contrast, chemical synthesis can generate a stable, rigid, and irreversible polymeric structure. Nowadays, the term “smart hydrogel” has gained significant attention due to its response to external factors, such as pH, temperature, light, electricity, and magnetic, and even an internal approach as substrate. Besides, the characteristics and properties of these polymeric matrices can be enhanced through the synergic relationship with nanoparticles. The inner and outer structure and the behavior of these materials can be studied through characterization techniques, such as light scattering, gel permeation chromatography, viscometry, thermal analysis, spectroscopies, microscopies, and swelling.