**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

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*Polymer Properties: Functionalization and Surface Modified Nanoparticles*

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 encap-

*DOI: http://dx.doi.org/10.5772/intechopen.84424*

sulate and entrap the drug molecules [59].

**9. Morphology and surface patterning of nanoparticles**

Scientists already developed different advanced techniques to examine the meso-, nano-, and micro-, and macroscale porosity within the polymer nanoparticles, and this porous surface patterning depends on the self-assembly of chosen materials. Polymer nanoparticles' preparation is fairly easy, and they show good control over the size and shape with longer clearance time. The extensive use of polymer nanoparticles has led to study the surface properties based on its pharmaceutical and industrial applications [57–61]. For example, PVA and PLA nanoparticles show unique characteristic properties to modify their surface with greater control of size. However, double emulsion techniques can be applied to stabilize the PVA nanoparticles. The protein containing nanoparticles has limitations on the increase of nanoparticle size upon functionalization with other nanomaterials. The protein bovine serum albumin (BSA) containing PLGA nanoparticles has good control on its size and shape while functionalizing through the solid-in-oil and oil-in-oil microsphere development method with suspended droplet hardening using impeller atomization followed by the droplet shearing in a spinning oil film approach. As shown in **Figures 7** and **8**, the gold nanoparticles have good interactions with polymer micelles and formed a new nanomaterial which is
