Organometallic Nanostructures: Self-Assembly of Poly(ferrocene) Block Copolymers

Abstract

Self‐assembly of block copolymers with incompatible segments is known to generate a variety of different morphologies, and provides an attractive, alternative route to nanostructures. The authors describe some of their recent collaborative work on novel organometallic nanostructures made possible by the recent synthetic access to poly(ferrocene) block copolymers (see Figure and also the cover).

Synthesis and Solution Self‐Assembly of Polyisoprene‐block‐poly(ferrocenylmethylsilane): A Diblock Copolymer with an Atactic but Semicrystalline Core‐Forming Metalloblock

“…This allows the formation of a variety of interesting nanostructured materials with periodic iron-rich domains and varied morphologies. 255 Following initial reports in the mid 1990s, 45 Figure 22. 230 Phase diagrams for both PS-b-PFDMS 258 and PS-b-PFEMS 48,218 BCPs have been reported previously.…”

“…R = R' = Me, PFDMS; R = R' = Et, PFDES) and is able to crystallise can self-assemble in various solvents to produce a number of different micellar morphologies including cylinders, 254,255,325 tubes, [326][327][328] fibres, 329 platelets 220 and, if the core-forming block does not crystallise, usually spheres. 47,225,330 As an example, when a sample of PFDMS50-b-PDMS300, with a block ratio of 1:6, was heated and cooled in a selective solvent for the PDMS block such as n-hexane, cylindrical micelles were obtained composed of a PFDMS core and a PDMS corona.…”

“…These nanostructures are easily visualised by TEM because the PFDMS core is electron-rich, allowing effective contrast for imaging without the need for staining. 255 The crystallisation of the core-forming PFDMS was believed to be the driving force for the formation of a cylindrical rather than spherical morphology, and the ordered nature of the core and the chain packing has been explored by wide angle X-ray scattering (WAXS). 7,331 Spherical micelles are obtainable in certain cases such as when cylindrical micelles are heated above the Tm of the PFS core-forming block and the solution is then rapidly cooled to prevent core-crystallisation or when an unsymmetrical PFS block, such as poly(ferrocenylethylmethylsilane) (PFEMS), is the core-forming block.…”

How a Small Modification of the Corona-Forming Block Redirects the Self-Assembly of Crystalline–Coil Block Copolymers in Solution

“…6,9,10 The first rod-like micelles reported involved poly(ferrocenyldimethylsilane) (PFS) block copolymers. [11][12][13] Other more recent examples of rod-like micelles involve block copolymers with polyethylene (PE), 7,[14][15][16][17][18][19][20] polyacrylonitrile (PAN), 21 polyferrocenyldimethylgermane (PFG), 22 poly(e-caprolactone) (PCL), [23][24][25][26][27][28][29][30] poly(L-lactide) (PLLA), [31][32][33][34][35] and polythiophene, 36,37 as the crystalline core-forming block.…”

“…11,45 Rod-like micelles are formed when the corona-forming block is longer than the PFS block. One of the remarkable features of PFS block copolymer micelles is that they undergo seeded growth.…”