Hollow Nanospheres from Polyisoprene-block-poly(2-cinnamoylethyl methacrylate)-block-poly(tert-butyl acrylate)

Abstract

A polyisoprene-block-poly(2-cinnamoylethyl methacrylate)-block-poly(tert-butyl acrylate), PI-b-PCEMA-b-PtBA, sample with 3.7 × 10 2 units of isoprene, 4.2 × 10 2 units of CEMA, and 5.5 × 10 2 units of tBA was synthesized. The triblock formed spherical micelles with a PtBA corona, PCEMA shell, and PI core in THF/methanol with methanol volume fractions between 50% and 99%. After micellar structure "locking in" by UV cross-linking of PCEMA, the PI block of the triblock was degraded by ozonolysis to yield nanospheres with a central cavity. The cavities were loaded with rhodamine B, a compound with size similar to those of many drug compounds.

Preparation of block copolymer vesicles in solution

“…Antonietti's group 79 used polybutadiene-block-poly(2-vinylpridine) (PB-b-P2VP) copolymers as templates for the synthesis of mesoporous silica. They found that, at a 50 wt % concentration of PB 210 -b-P2VP 99 in an aqueous solution, the 100 -150 nm pores were filled with multilamellar vesicles. Maskos and Harris 80 obtained double-shell vesicles and strings of vesicles from crosslinking poly(1,2-butadiene)-blockpoly(ethylene oxide) copolymers (PB 27 -b-PEO 28 ).…”

Colloidal Nanoreactors and Nanocontainers

“…It has been shown that the PAA shell can be cross-linked with a,x-diamino-poly(ethylene glycol) [50]. Similarly, a poly(isoprene)-b-poly(2-cinnamoylethyl methacrylate)-b-poly(tert-butyl acrylate) (PI-PCEMA-PTBA) triblock copolymer forms micelles with a PTBA corona, PCEMA shell and a PI core in THF-methanol mixtures [51]. In this case the micellar structure could be locked in by UV-cross-linking of the PCEMA within the micelles.…”

Chemistry in block copolymer nanocontainers : self-assembly, container properties and confined enzymatic reactions

“…58 Similarly, a poly(isoprene)-block-poly(2-cinnamoylethyl methacrylate)-block-poly (tert-butyl acrylate) (PI-PCEMA-PTBA) triblock copolymer forms micelles with a PTBA corona, PCEMA shell and a PI core in THF and methanol mixtures. 59 In this case the micellar structure could be locked in by UV crosslinking of the PCEMA within the micelles. Subsequently the PI cores of both the crosslinked PI-PAA and the PI-PCEMA-PTBA micelles could be degraded by ozonolysis into small fragments that diffuse into the surrounding solution and nanospheres with a central cavity are left behind as produced.…”

“…58 The potential of such systems for encapsulation of small molecules has been demonstrated by loading the crosslinked PCEMA-PTBA capsules with rhodamine B. 59 The incorporation of the dye into the central cavity of the particles could directly be visualized by TEM. The degradation of the shell crosslinked PI-PAA micelles leads to water-soluble crosslinked poly(acrylamide) hollow spheres, which possess considerably larger hydrodynamic diameter of their shells after removal of the core.…”

“…The redox-control of the permeability of composite-wall capsules with five PFS -/PFS + polyion pairs as inner layers and redox-insensitive polyelectrolyte pairs 96 , it is also possible to produce real hollow structures from dendrimers. This has recently been demonstrated using a polyether dendrimer with a trimesic acid ester core.…”