Hairy PEO‐Silica Nanoparticles through Surface‐Initiated Polymerization of Ethylene Oxide

Abstract

Summary: The grafting of poly(ethylene oxide) (PEO) onto silica nanoparticles was performed in situ by the ring‐opening polymerization of the oxirane monomer initiated from the mineral surface using aluminium isopropoxide as an initiator/heterogeneous catalyst. Alcohol groups were first introduced onto silica by reacting the surfacic silanols with prehydrolyzed 3‐glycidoxypropyl trimethoxysilane. The alcohol‐grafted silica played the role of a coinitiator/chain‐transfer agent in the polymerization reaction and enabled the formation of irreversibly bonded polymer chains. Silica nanoparticles containing up to 40 wt.‐% of a hairy layer of grafted PEO chains were successfully produced by this technique.

Synthesis of poly(ethylene glycol) (PEG)-grafted colloidal silica particles with improved stability in aqueous solvents

“…The TEM image of the PEGgrafted particles shows gray zones of low contrast that are not shown on the image of the pre-coated particles. The same difference before and after PEG grafting was also found by Joubert et al [9], who attributed the gray zones to the PEG grafting. The agreement between their results and our result is an indication that we can see the grafted PEG with TEM.…”

“…Joubert et al [9] are the only researchers who prepared PEO-grafted silica with the so-called "grafting from" method in which the grafting polymer is grown from the surface of the particles, contrary to the method used by all others (including us) who linked pre-made polymers to the particles, the so called "grafting onto" method. The method yields high grafting densities, but so far the grafted polymers are of low molecular weight and have a broad molecular weight distribution.…”

Facile Access to Hydroxy‐Functional Core–Shell Microspheres via Grafting of Ethylene Oxide by Anionic Ring‐Opening Polymerization

“…Under the assumption that the PEO chains collapse on the surface of the microspheres upon drying to form a dense polymer shell, the diameter of the grafted particles, D g , can be calculated: [19] D g ¼D c ð1þw p Þ 1=3 (5) where D c is the diameter of the core PDVB microspheres before grafting, and w p is the weight of the grafted polymer (0.057 g per gram of microspheres). The number average particle diameter of the core PDVB microspheres, determined by SEM, is 3.5 mm.…”

“…Joubert et al used catalytic ring-opening polymerization to graft EO from silica nanoparticles. [19] This method requires the silica surfaces to be first pre-hydrolyzed with a silane and subsequently be reacted with a metal alkoxide. In addition, they also grafted e-caprolactone and D-lactide from the surface of silica nanoparticles by anionic ring-opening polymerization (AROP).…”

Silica nanoparticle-based dual imaging colloidal hybrids: cancer cell imaging and biodistribution

“…Surface-modified silica nanoparticles afford the feasibility of combining various functionalities onto the silica surface. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] Moreover, they have good water wettability and low cytotoxicity for in vivo application. 22 Cellular imaging agents must produce adequate real-time diagnostic images.…”