**3.2 Polymers**

Polymer materials are composed of chemical compounds typically formed from monomers of carbon, hydrogen, oxygen and nitrogen. These monomer structures repeat and bind with themselves to create long molecular chains. Polymers have gained importance for fabrication of scaffolds as they are inexpensive, biocompatible, biodegradable and can be easily manipulated for their chemical, mechanical and biological properties. The commonly used polymers in craniofacial tissue engineering include natural polymers and synthetic polymers [3]. Natural polymers can be categorized into two main subgroups e.g. polysaccharides (alginate, cellulose, starch, chitosan) and polypeptides and proteins (collagen, silk fibroin, albumin) [31], whereas synthetic polymers majorly include polycaprolactone (PCL), poly lactic acid (PLA), poly(l-lactic) acid (PLLA), poly D, L-lactide-co-glycolic acid (PLGA), polyvinylidene fluoride (PVDF) and magneto-responsive polymeric systems [3, 41, 42].

Synthetic materials such as PVDF (poly (vinylidene fluoride)), P(VDF-TrFE) co-polymer of vinylidene fluoride (VDF) and trifluoroethylene (TrFE), PHBV (poly-3-hydroxybutyrate-3-hydroxy valerate), poly-l-lactic acid (PLLA) and natural polymers such as cellulose, collagen, silk and chitin, exhibit piezoelectric properties and hold a great promise in the field of bone tissue engineering [33].
