Hollow polymeric nanospheres

Of late, significant interest has been paid to hollow polymeric nanostructures (HPNSs) because of the new functionalities and unique physiochemical properties anticipated from polymeric materials at the nanoscale. The development of HPNSs is reflected by the rapid increase in the number of scientific publications and patents on this subject in recent years. HPNSs in the size range of 1-1,000 nm with spherical or cylindrical geometries are of special interest. Spherical HPNSs generally include hollow polymeric nanospheres (HPNSPs), vesicles, or nanopoly-mersomes. Cylindrical HPNSs are basically polymeric nanotubes (PNTs). In view of possible biomedical applications, HPNSPs are potentially useful as encapsulates... 

Fig. 11 Preparation of hollow polymeric nanospheres via water-oil-water emulsion polymtaization...

Jang, J. and Ha, H. (2002) Fabrication of hollow polystyrene nanospheres in microemulsion polymerization using triblock copolymers. Langmuir, 18,5613-5618. 

Sasidharan, M., Zenibana, H., Nandi, M., Bhaumik, A., and Nakashima, K. (2013) Synthesis of mesoporous hollow silica nanospheres using polymeric micelles as template and their application as a drug-delivery carrier. Dalton Trans., 42, 13381-13389. 

Figure 6.4 The preparation of nanostructured materials in solution evolves from (a) the classic examples of suspension, dispersion, or emulsion polymerization, to the methods that include the covalent crosslinking of select domains within supramolecular polymer assemblies (b) core crosslinking of polymer micelles (c) shell crosslinking of polymer micelles (SCKs) (d) nanocages from core-eroded SCKs (e) shaved hollow nanospheres from outer shell/core-eroded vesicles.

Nanospheres are hollow nanosized particles (Figure 47.1C) that can be prepared by microemulsion polymerization or covering the surfaces of colloidal templates with thin layers of the desired material followed by selective removal of the templates (Hyuk Im et al., 2005). The carboxylated polystyrene nanospheres (20 nm) were evaluated for drug delivery... 

Fig. 15.24. Schematic depiction of the polymerization of monomers within the vesicle bilayer leading to the formation of hollow nanospheres. (Reprinted with permission from Langmuir, 1998, 14, 1031. 1998 American Chemical Society [87].)...

D.M. Cheng, X. Zhou, H. Xia, and H.S.O. Chan, Novel method for the preparation of polymeric hollow nanospheres containing silver cores with different sizes, Chem. Mater., 17(14), 3578-3581 (2005). 

Recently, a novel approach to PPy hollow nanospheres has been developed using core-shell nanomaterial composed of an identical polymer [84,223]. The core-shell nanoparticle composed of only PPy was generated via the microemulsion polymerization using two oxidizing agents with different chemical oxidation potentials, and used as a precursor for the fabrication of the PPy hollow nanoparticle (Scheme 7). In the synthetic procedure of PPy... 

Several reports related to PEDOT-coated particles and PEDOT hollow particles have been pronounced in the literature [359,360]. Dispersion polymerization has been applied for PEDOT-coated PS particles fabrication. 100 nm PS nanoparticle was used as the core material [359]. hi order to improve the stability of the PS particle, DBSA was used as the surfactant. It was presumed that hydrophobic alkyl chains of the surfactant were positioned towards the surface of PS particles and the sulfonic acid group toward the water phase. EDOT monomer was adsorbed on the surface of the PS nanosphere and polymerization was initiated by the addition of the APS oxidant. PS-PEDOT core-shell structure was distinctively visualized by TEM. The doped PEDOT shell had a higher electron density than the PS core and the thickness of the PEDOT shell was ca. 8 nm. 

Nanoparticles, i.e. particles with a size usually in the range 50-1000 nm, have drawn the attention of researchers designing drug-delivery systems that can be injected intravenously owing to their small size. Nanoparticle is a general name for nanospheres and nanocapsules. Nanospheres have a matrix-type structure, whereas nanocapsules are hollow and have a liquid core surrounded by a polymeric wall, as illustrated in Figure 4.34. 

Sasidharan, M. and Nakashima, K. (2013) Core shell corona polymeric micelles as a versatile template for synthesis of inorganic hollow nanospheres. Acc. Chem. Res., 47 (1), 157 167. 

In particular, the pH-responsive block copolymers are very important because they can form NPs, for example, polymeric micelles, vesicles or hollow nanospheres, in aqueous media via the changing environment, and further provide a variety of applications for the biomedical fields. 

Synthesis of hollow metal oxide nanospheres by templating polymeric micelles with core-shell-corona architecture. Inorg, Chem., 48,... 

Fu GD, Shang Z, Hong L, Kang ET, Neoh KG (2005) Preparation of cross-linked polystyrene hollow nanospheres via surface-initiated atom transfer radical polymerizations. Macromolecules 38 7867-7871... 

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