Layer-by-layer assembly of imogolite nanotubes and polyelectrolytes into core-shell particles and their conversion to hierarchically porous spheres

Abstract

Core-shell particles were prepared by the layer-by-layer (LbL) assembly of imogolite (IMO) nanotubes and poly(sodium 4-styrenesulfonate) (PSS) on polystyrene particles (diameter: 800 nm) coated preliminarily with poly(diallyldimethylammonium chloride) (PDDA). PSS and imogolite were alternately adsorbed on the particles to form core-shell particles with one to three bilayers of PSS/IMO. Macroporous hollow spheres were formed by removing polystyrene cores via heat treatment or extraction when the number of bilayers was 2 or 3. The sample formed by extraction (the number of bilayer was 3) showed only macroporosity and PSS remained in the shell, whereas the heat-treated sample showed hierarchical micro-and macroporosities. When the diameter of polystyrene particles decreased from 800 nm to 300 or 100 nm, hollow spheres were deformed because of the increase in the relative length of imogolite nanotubes against the size of polystyrene particles. Imogolite is a promising building block of hierarchically porous materials with core-shell morphologies using LbL assembly.

Confined growth of CuO, NiO, and Co3O4 nanocrystals in mesoporous silica (MS) spheres

“…4 and the parameters derived from these isotherms are listed in Table 1. It can be seen that in all cases, the isotherms are of type IV according to the IUPAC classification and exhibit H3-type hysteresis loops, characteristic of samples with slit-like mesopores [26].…”

“…Polyelectrolytes were assembled by the sequential deposition of PAH and PSS onto M 2+ (Cu 2+ , Ni 2+ , and Co 2+ )-adsorbed mesoporous silica spheres using the layerby-layer (LbL) technique [26]. Briefly, the as-prepared M 2+ (Cu 2+ , Ni 2+ , and Co 2+ )-adsorbed MS particles were dispersed in 6 mL of PAH (1 g L −1 ) containing 0.5 M NaCl.…”

Effective use of flexible low-dimensional colloidal particles and colloidal crystals for the control of hierarchically porous materials

“…Imogolite nanotubes and poly-(sodium 4-styrenesufonate) (PSS) were deposited layer-by-layer on the surface of PS particles to form coreshell particles. 89) Hierarchically porous hollow spheres can be obtained by subsequent removal of templates [ Fig. 5(b)].…”

Bio-Inspired/-Functional Colloidal Core-Shell Polymeric-Based NanoSystems: Technology Promise in Tissue Engineering, Bioimaging and NanoMedicine

“…For many years, liposome-based core-shell designed preparations have found applications in cell membrane modelling, drug and growth factor delivery as well as transfection; overcoming past shortcomings associated with cytocompatibility, malleability, stability and the phospholipid vesicle size, monodispersity and membrane permeability, via the L-b-L incorporated-support of polyelectrolytes [20,23]. Other investigators have even explored coating polymeric core-shell particles with different asymmetric bi-layer as well as inorganic-based phospholipid membranes such as poly(diallyldimethylammonium chloride) and poly (sodium 4-styrenesulfonate) [38]. Such systems have found suitability for studying membrane recognition, signal transduction processes as well as controlled drug release [38,39].…”

“…Other investigators have even explored coating polymeric core-shell particles with different asymmetric bi-layer as well as inorganic-based phospholipid membranes such as poly(diallyldimethylammonium chloride) and poly (sodium 4-styrenesulfonate) [38]. Such systems have found suitability for studying membrane recognition, signal transduction processes as well as controlled drug release [38,39]. Now, while traditional nanoparticles with hydrophobic surfaces are rapidly opsonized and cleared by the bodily reticulo-endothelial and mononuclear phagocytic systems, targeted therapeutic delivery requires the persistence of nanoparticulate systems throughout the systemic circulation of the body [40].…”