*Polymer Properties: Functionalization and Surface Modified Nanoparticles DOI: http://dx.doi.org/10.5772/intechopen.84424*

*Role of Novel Drug Delivery Vehicles in Nanobiomedicine*

meric and non-polymeric nanoparticles.

**8. Preparation and functionalization of polymer nanoparticles**

However, polymer nanoparticles can be prepared through various approaches through the monomer to polymer formation trajectory which is scientifically called as polymerization reactions followed by the development of nanoparticles. Interestingly, the group transfer polymerization (GTP), ring-opening polymerization (ROP), radical polymerization (RP), polymer re-precipitation (PRP), emulsion, micro radical polymerization (MRP), macro polymer initiation reactions (MPIR), addition polymerization reactions (APR), emulsion polymerization (EP), atom transfer radical polymerization (ATRP), addition polymerizations (AP), condensation polymerization (CP), oxidation polymerization (OP), and reduction polymerization (RDP) followed by the redox reactions and self-assembly approach of polymer materials are used to design and develop nanoparticles from the synthesized polymers. The hydrophobic and hydrophilic nature of polymers followed by the amphiphilic character has been considered while performing the polymerization reactions to develop nanoparticles [52–56]. After synthesis of the polymer by using any of the abovementioned polymerization reactions, the final compound can be used for morphological characterizations. Sometimes solid powder form of the sample can be used directly for SEM and TEM characterizations. But for polymeric samples, it needs to be dispersed in the suitable solvent before going

accurate mass of the synthesized compounds, matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) to measure the molecular mass of heavier compounds such as polymer macromolecules, mass of genetic materials such as deoxyribonucleic acid (DNA), ribonucleic acid (RNA) and other biomolecules, carbon, hydrogen, nitrogen, sulfur (CHNS) analyzer. Once the synthesized molecules are confirmed, then it needs microscopic characterizations for the morphology of polymeric nanoparticles. Morphology of polymer nanoparticles has been characterized by using scanning electron microscope (SEM), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) for morphology of nanoparticles, X-ray diffraction (XRD) to know the solid state and nature of materials such as amorphous, crystalline and partially crystalline nature of synthesized nanoparticles, energy dispersive spectroscopy (EDAX) for the presence of elements and elemental composition in the final compound, Brunauer–Emmett–Teller (BET) to measure the BET surface area, porosity, pore width, pore thickness, specific surface area, Langmuir surface area through the nitrogen (N2) gas adsorption and desorption hysteresis curve analysis, Atomic force microscope (AFM) for surface properties like smooth/hard/rough surface of the polymer and non-polymer nanoparticles followed by the pore profile such as pore depth and width in case of porous capsules or particles, apart from this characterization Optical profilometer can also use to evaluate the surface properties of nanoparticles and thin films. To examine the thermal properties and degradation behavior of nanoparticles, the following characterization techniques are used such as differential scanning calorimetry (DSC) for heat flow measurements such as endo- and exothermic nature of particles. Endothermic has been defined as the system which absorbs heat from surrounding and exothermic the system which releases heat to surroundings, thermogravimetric analysis (TGA) for weight loss and degradation temperature of various nanoparticles, Raman to measure the band gap, dynamic light scattering (DLS) for particle size analysis, zeta potential to measure the charge of the poly-

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for morphological characterizations. Dispersion followed by the sonication, stirring, ultra-sonication, shaking, etc. based on particle aggregation and segregation tendency dispersion methods needs to be chosen. During the dispersion followed by the sonication, there are certain precautions needed to be taken care of such as sonication time, bath temperature, etc. Bath temperature and sonication time have to be optimized; otherwise structural disintegration or polymer particles may get collapsed or disrupted with over sonication and temperature conditions. Apart from the abovementioned methods, there are several modified chemical synthesis routes to approach to elucidate the nanoparticle design and development based on their applications. Nanoparticle formulation and functionalization depends on the synthesis methods and desired characteristic features of the polymers chosen [57]. Charged nanoparticles may have the tendency to attract or repel with other nanomaterials. In general, the size of nanoparticles increases upon blending with some other nanomaterials, and it leads to form bulk materials. For example, polystyrene (PS) nanoparticles followed by the sulfonation lead to increase the composite size. The swelling and dispersion and diffusion nature of nanoparticles lead to enhance the size of nanoparticles, and this is because of the additional functionalization. The monodispersion approach helps to get the uniform-sized nanoparticles with desired surface properties [58]. The synthesis approaches, nanoformulations, and functionalization of nanocarrier capsules and particles are very important in the drug delivery systems. And this can be achieved through the synthesis methods like ring-opening polymerization, polymer precipitation, selfassembly of polymer materials, etc. Polymers are having the capability to form the network-like structures due to its functional group entanglement and orientation to get the stability in its structure internally. The chain cross-linking and branching nature hyper-branching also lead to the functionalization of polymer nanoparticles. The synthesis of nanocarriers like nanocapsules, nanospheres, and nanoparticles with the characteristic features such as with the mesoscale porosity (pore diameter is 2–50 nm), nanoporous (pore diameter ~100 nm), microporous (pore diameter ~2 nm) and cavities, voids, and core-shell concept is important to absorb or encapsulate and entrap the drug molecules [59].
