| Functionalization | Synthesis | Characteristic | Application | Reference |
| Cross-linking | With glutaraldehyde and sulfosuccinic acid | Protonic conductivity | Membrans for Fuel cells | [141] |
| Cross-linking | With di- and tri-carboxylic acids | nano-hydrogels | Drug release | [142] [143] |
| Graft copolymerization | Copolymerization of metacrylic acid with chitosan in the presence of APS | Improved water solubility | Antibacterial activity | [144] |
| Graft copolymerization | Copolymerization of maleic acid with (CMCTS) and (HPCTS) | Improved scavenging ability | Antioxidant activity | [145] |
| Graft copolymerization | Copolymerization of aniline with chitosan | Protonic conductivity | Conductive films and fibers | [146] |
| Carboxymethylation | Monochloroaetic acid | Solubility depends on pH | Antimicrobial activity, affinity with metal ions, Controlled release of drugs | [147] |
| Phosphorylation | Heating chitosan with orthophosphoric acid in DMF or with phosphorous pentoxide in methanesulphonic acid | Solubility in water under neutral conditions | Bactericidal, biocompatible, bioabsorbable, osteoinductive and metal chelating properties | [148] |
| Esterification | Reaction of acyl chlorides with chitosan (synthesis of N,O-Acyl chitosan derivatives) | Reaction mainly occurred on the OH group and not on the NH2 group | Highly improved antifungal activity | [149] |
| Etherification | Synthesis of N-phthaloyl chitosan. (MPEG) iodide | Soluble in water and aqueous solutions of wide pH range | Extremely low reduced viscosity | [150] |
| Self-rearrangement of polymer networks | chitosan/chondroitin sulfate formed by polyelectrolyte complexation | Crystallinity, higher thermal stability, porosity, and water uptake capacity | pH sensitive material which can be tailored to several specific applications | [151] [152] |
| BC/Ch composite preparation | Immersing wet BC pellicle in chitosan solution followed by freeze-drying | porous network structure and large aspect surface | Wound dressing or tissue-engineering scaffolds | [153] |
| Reversible blending | Mixing of chitosan/PHEMA | Swollen structure | Electrically sensitive behavior | [154] |
| Electrospun chitosan fibers | Electro-wet-spinning (submicron scale) | Fast and reversible electroactuation | Application in artificial muscles | [155] |
| Blending of chitosan and Cellulose | Preparation of chitosan/cellulose blend beads | Blend beads with rough and folded surface morphology | Odor treatment and metal ions adsorption | [156] |
|
| Casting of a TFA solution of chitosan and cellulose | Large bending displacement under low voltage | Blended dry and durable actuator | [157] |
| Blending of chitosan with PCL | Chitosan and PCL homogeneously dissolved in acetic acid/water and processed into uniform membranes | Blends with chemical bonds | biological and anti-bacterial properties | [158] |
| Preparation of poly(AA-co AM)/(O-CMC) interpenetrating polymer network | Synthesis of a semi-IPN by AA and AM copolymerization of in the presence of O-CMCthen synthesis of a full-IPN through cross-linking | Superporous hydrogel | Mucosal drug delivery system, especially for peroral delivery of peptide and protein drugs | [159] |