Hierarchical Ionic Self-Assembly of Rod−Comb Block Copolypeptide−Surfactant Complexes
- 15 November 2006
- journal article
- Published by American Chemical Society (ACS) in Biomacromolecules
- Vol. 7 (12), 3379-3384
- https://doi.org/10.1021/bm0606770
Abstract
Novel hierarchical nanostructures based on ionically self-assembled complexes of diblock copolypeptides and surfactants are presented. Rod−coil diblock copolypeptide poly(γ-benzyl-l-glutamate)-block-poly(l-lysine), PBLG-b-PLL (Mn = 25 000 and 8000 for PBLG and PLL, respectively, polydispersity index 1.08), was complexed with anionic surfactants dodecanesulfonic acid (DSA) or dodecyl benzenesulfonic acid (DBSA), denoted as PBLG-b-PLL(DSA)1.0 and PBLG-b-PLL(DBSA)1.0, respectively. The complexation leading to supramolecular rod−comb architectures was studied by transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), Fourier transform infrared spectroscopy (FTIR), and polarized optical microscopy (POM). PBLG-b-PLL, PBLG-b-PLL(DBSA)1.0, and PBLG-b-PLL(DSA)1.0 self-assemble with alternating PBLG lamellae and PLL-containing lamellae with a periodicity of 27−33 nm. Within the PBLG lamellae, the rod-like PBLG helices pack with a periodicity of ca. 1.3 nm. The internal structure of the PLL-containing lamellae depends on the complexation. For pure PBLG-b-PLL, the PLL chains adopt a random coil conformation and the PLL domains are disordered. For PBLG-b-PLL(DSA)1.0, lamellar self-assembly of periodicity of 3.7 nm within the PLL(DSA)1.0 domains is observed due to crystalline packing of the linear n-dodecyl tails. For PBLG-b-PLL(DBSA)1.0 with branched dodecyl tails, a distinct SAXS reflection is observed, suggesting self-assembly within the PLL(DBSA)1.0 domains with a periodicity of 2.9 nm. However, due to the absence of higher order reflections, the internal structure cannot be conclusively assigned. The efficient plasticization which leads to fluid-like liquid crystallinity in PBLG-b-PLL(DBSA)1.0 and an α-helical conformation according to FTIR allows us to suggest that the PLL(DBSA)1.0 domains have a hexagonal internal structure. The interplay of self-assembly at different length scales combined with rod-like liquid crystallinity can open new routes to design functional materials.Keywords
This publication has 37 references indexed in Scilit:
- Thermotropic Polypeptides Bearing Side-On MesogensMacromolecules, 2005
- Solid-state structure of polypeptide-based rod-coil block copolymers: Folding of helicesThe European Physical Journal E, 2004
- Rod–rod and rod–coil self-assembly and phase behavior of polypeptide diblock copolymersPolymer, 2004
- Multicomb Polymeric Supramolecules and Their Self‐Organization: Combination of Coordination and Ionic InteractionsMacromolecular Rapid Communications, 2003
- Solid-state morphologies of linear and bottlebrush-shaped polystyrene–poly(Z-l-lysine) block copolymersPolymer, 2002
- Direct Imaging of Self-Organized Comb Copolymer-like Systems Obtained by Hydrogen Bonding: Poly(4-vinylpyridine)−4-NonadecylphenolMacromolecules, 1998
- Thermoreversible Gels of Polyaniline: Viscoelastic and Electrical Evidence on Fusible Network StructuresMacromolecules, 1997
- Comb-like and block liquid crystalline polymers for biological applicationsProgress in Polymer Science, 1996
- Molecular Self-Assembly and Nanochemistry: a Chemical Strategy for the Synthesis of NanostructuresScience, 1991
- Block copolymers with a polyvinyl and a polypeptide block: factors governing the folding of the polypeptide chainsPolymer, 1982