Extended Self-Assembled Long Periodicity and Zig-Zag Domains from Helix–Helix Diblock Copolymer Poly(γ-benzyl-l-glutamate)-block-poly(O-benzyl-l-hydroxyproline)

Abstract

We describe the synthesis and self-assembly of particularly high periodicity of diblock copolymers composed of poly(benzyl-l-hydroxyproline) (PBLHyP) and poly(γ-benzyl-l-glutamate) (PBLG), that is, two polypeptide blocks with dissimilar helical structures. The robust helicity of the PBLHyP block is driven by steric constraints of the repeat units, while PBLG forms α-helices driven by hydrogen bonding, allowing defects and deformations. Herein, high-molecular-weight diblock copolypeptides of PBLG-b-PBLHyP with three different volume fractions of the PBLHyP-blocks are discussed. For shorter PBLHyP blocks, hexagonal packing of PBLHyP helices is observed, while by increasing the length of the PBLHyP block, keeping at a similar PBLG block length, the packing is distorted. Zig-zag lamellar structures were obtained due to the mismatch in the packing periodicities of the PBLG and PBLHyP helices. The frustration that takes place at the interface leads the PBLHyP to tilt to match the PBLG periodicity. The zig-zag morphology is reported for the first time for high-molecular-weight helix-helix (rod-rod) copolypeptides, and the self-assembled periodicity is uncommonly large.

Self-assembly of rod-coil-rod triblock copolymers: A route toward hierarchical liquid crystalline structures

“…21 The formation of zig-zag lamellar structures is due to the mismatch in the packing periodicities of the PBLG and PBLHyP helices. These structures are similar to the IA-HS C L where the two kinds of rod blocks are respectively inclined to form interdigitated-arrowhead structures (see Figure 6c3).…”

“…[9][10][11] Recently, hierarchical microstructures with multiple periods at different length scales have attracted great interests, which focus on the design of various hierarchical structures by tuning molecular topologies and chain compositions. [12][13][14][15][16][17][18][19][20][21][22][23][24] These structures are mainly prepared by the selfassembly of flexible copolymers. In contrast, the experimental studies on the hierarchical LC structures are very limited.…”

“…In contrast, the experimental studies on the hierarchical LC structures are very limited. [20][21][22][23][24] The copolymers consisting of two kinds of rod blocks are one candidate for self-assembling into hierarchical LC structures. Iatrou et al synthesized poly(γ-benzyl-L-glutamate)-b-poly(L-proline) (PBLG-b-PLP) polypeptides in which both the PBLG and PLP adopt rigid helical conformations.…”

“…21 Haataja et al invesitigated the self-assembly behavior of poly(γ-benzyl-L-glutamate)-block-poly(Llysine) (PBLG-b-PLL) in which the PLL amino residues were ionically complexed to di-n-butyl phosphate (diC4P). 22 These PBLG-b-PLL(diC4P) rod-rod systems were found to form double M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 4 smectic-like structures with alternating PBLG and PLL(diC4P) smectic layers of approximately perpendicular alignment of both types of α-helices.…”

Polypeptide‐b‐Poly(Phenyl Isocyanide) Hybrid Rod‐Rod Copolymers: One‐Pot Synthesis, Self‐Assembly, and Cell Imaging

“…A thorough solution is the combination of two homopolymers with desired self-assembly behavior and corresponding properties into a block copolymer to afford highly controlled ordered morphologies and allow related applications. [1][2][3][4][5][6][7] In this context, artifi cial block copolymers containing a helical polymer are of great interest, not only due to their optical activity but also for their numerous applications in enantiomer separation, chiral recognition, and liquid crystals. [8][9][10][11] Polypeptides are well known segments that exhibit rod-like conformations.…”