**Abstract**

Herein, the various polymer properties and the underlying mechanism for the functionalization and surface modification of polymer nanoparticles have been discussed. There are numerous polymer particles designed and developed for various applications. The synthesis and characterization of different types of polymers followed by the engineering of nanoparticles and capsules depend on various factors. There are too many polymerization methods approached for the development of nanoparticles with desired surface properties. The ring-opening polymerization (ROP), emulsion polymerization (EP), atom transfer radical polymerization (ATRP), and free radical micro initiation are the significant approaches for the polymerization reactions. The polymer nanoparticle functionalization and modification of their surfaces based on requirements is an essential task. The solvent concentration, pH, temperature, and sonication have played a vital role to tune the morphology of polymer nanoparticles and capsules. Different characterizations such as FTIR, NMR ( 1 H and 13C), HRMS, and MALDI-TOF are used for preliminary structural and confirmations. Further, SEM, FE-SEM, TEM, AFM, BET, XRD, Raman, EDAX, TGA-DSC, DLS, and zeta potential were used for morphological and thermal properties.

**Keywords:** polymers, properties, functionalization, surface modification, nanoparticles
