Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2016)
    Nanomaterials Tuesday Sessions
       Session NM-TuP

Paper NM-TuP7
High Elastic Modulus, High Extensibility Nanorods Constructed of pH-Responsive Cyclic Peptide Polymer

Tuesday, December 13, 2016, 4:00 pm, Room Mauka

Session: Nanomaterials Poster Session
Presenter: Kenan Fears, US Naval Research Laboratory, USA
Authors: K. Fears, US Naval Research Laboratory, USA
M. Kolel-Veetil, US Naval Research Laboratory, USA
D. Barlow, US Naval Research Laboratory, USA
N. Bernstein, US Naval Research Laboratory, USA
C. So, US Naval Research Laboratory, USA
K. Wahl, US Naval Research Laboratory, USA
Correspondent: Click to Email
Due to their ability to self-assemble into supramolecular nanorods in solution, cyclic β -tripeptides (CBTPs) have been used as molecular scaffolds that predictably display functional groups along the axis of the assembly. To enhance the mechanical strength and processability of such nanostructures, we synthesized a linear polymer of amide-bonded CBTP subunits using previous computational analysis on the conformational stability and tunability as guidance. Two amino acids in each subunit ( β -HLys or β -HGlu) form “hinges” with neighboring subunits, and electrostatic repulsions between the third, β -HOrn, forced the polymer to adopt a disordered conformation when protonated. When deprotonated, atomic force microscopy revealed rigid nanorods exhibiting an elastic moduli (51.3 GPa) stiffer than any report peptide-based material. The hinges also allow the nanorods to elongate under tension which should impart the polymer with high extensibility and resilience. Nanorods were decorated with Au nanoparticles to demonstrate the ease in functionalizing the polymer, greatly expanding its potential applications beyond a structural material. The solubility and structural control achieved by combining covalent bonds, non-covalent bonds, and electrostatic interactions suggest the polymer may not only exhibit excellent processability but also mimic toughness and elasticity found in nature.