Synthesis and Self-Assembly Studies of Amphiphilic Poly(n-hexyl isocyanate)-block-poly(2-vinylpyridine)-block-poly(n-hexyl isocyanate) Rod−Coil−Rod Triblock Copolymer

Abstract

Rod-coil-rod triblock copolymers of 2-vinylpyridine (2VP) and n-hexyl isocyanate (HIC) were synthesized by living anionic polymerization. The homopolymerization of 2VP was carried out at -78 °C in THF by using bidirectional initiators sodium naphthalenide (Na-Naph) and potassium naphthalenide (K-Naph). Block copolymerization with HIC was performed at -98 °C in the presence of sodium tetraphenylborate additive. While K-Naph yields copolymers of broad molecular weight distribution, Na-Naph was quite effective in facilitating a high degree of control over the copolymerization. The block copolymers containing higher rod volume fraction showed lamellar microphase separation in THF, a common solvent for both the rod and the coil blocks. The self-organization of the copolymer in solvents selective for one block was quite fascinating in that in CHCl 3 solid micelles of ∼20 nm were formed, whereas large hollow micelles of ∼200 nm were generated in CH 3 OH.

Self-assembled block copolymers: Bulk to thin film

“…[268][269][270][271][272] Finally, block copolymers having a rigid rod block are synthesized. [273][274][275][276][277][278][279][280][281] These block copolymers exhibit unique electric (or photoelectronic) properties and can be used as organic (or plastic) solar cells. 273,274 Typical rigid blocks are poly(p-phenylene vinylene) (PPV), poly(3-hyxyl thiopene), and poly(hexyl isocyanate), while the counterpart blocks are PS, PMMA, PI, and P2VP.…”

“…This shows nanofiber structure at low volume fraction of P2VP, but with increasing volume fraction of P2VP, lamellar and cylindrical microdomains are observed. 278 Lee and coworkers [279][280][281] showed that rodlike poly(n-hexylisocyanate) (PHIC) chains in PHIC-b-poly-(2-vinylpyridine)G (P2VP) was highly oriented and anisotropic organized as a self-assembled monolayer through lyotropic liquid crystalline ordering on a substrate surface.…”

A New Supramolecular Route for Using Rod‐Coil Block Copolymers in Photovoltaic Applications

“…[14][15][16][17][18][19] Block copolymers composed of an electron-donating and an electronaccepting block are therefore particularly interesting for PV applications and are presently studied worldwide by several research groups. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] Particularly, rod-coil block copolymers using poly[(2,5-di(2-ethyl)hexyloxy)-1,4-phenylenevinylene] (DEH-PPV) as electron donor and various coil blocks (such as polystyrene or polybutylacrylate) with covalently linked fullerene moieties as electron acceptor have been investigated intensively. [23][24][25][26][27][28] Although these studies have given considerable insight into the physics of copolymer self-assembly, their efficient utilization as the active layer in PV devices has not yet been fully demonstrated.…”

Synthesis and self-assembly of fluorene-vinylene alternating copolymers in “Hairy-Rod” architecture: side chain – mediated tuning of conformation, microstructure and photophysical properties

“…On the other hand, the block-copolymer self-assembling may take place in a non-selective solvent when other specific interactions exist, [78] which is also the case for a rod-coil block-copolymer. [79] The data presented in Table 2, referring to the copolymer 9 in chloroform solution, support the supposition that it exists in solution in assembled form, the particles with the highest size being in the highest percentage. In the aFM height image, (Figure S21(b)), the film surface of the copolymer 9 shows an interconnected cellular structure likely to be formed from fused isolated lamellae during solvent evaporation.…”