**10. Conclusions**

Herein, polymer synthesis, design, and development of nanoparticles and their functionalization have been discussed in detail. The various polymerization methods and different types of nanoparticles and capsules were reported in this chapter. The nanoparticle/capsule classification and surface functionalization followed by size, shape, and morphological changes based on industrial and biomedical applications have been corroborated. The polymer properties play a key role in the development of NPs with desired features, and such influencing factors were reported and elaborated in the respective sections. Nanoparticles and capsules with significant changeable surface and with a more specific surface area have potential applications in various fields. The porosity on the surface of nanoparticles and capsules is an important concern to prepare the NPs for both industrial and pharmaceutical applications.
