Complexation-Driven Mutarotation in Poly(L-proline) Block Copolypeptides.

Novel poly(L-lysine)-block-poly(L-proline) (PLL-b-PLP)-based materials with all PLP helical conformers, i.e., PLP II and the rare PLP I are here reported.

Molecular engineering of fracture energy dissipating sacrificial bonds into cellulose nanocrystal nanocomposites.

Even though nanocomposites have provided a plethora of routes to increase stiffness and strength, achieving increased toughness with suppressed catastrophic crack growth has remained more challenging. Inspired by the concepts of mechanically excellent natural nanomaterials, one-component nanocomposites were fabricated involving reinforcing colloidal nanorod cores with polymeric grafts containing supramolecular binding units. The concept is based on mechanically strong native cellulose nanocrystals (CNC) grafted with glassy polymethacrylate polymers, with side chains that contain 2-ureido-4[1H]-pyrimidone (UPy) pendant groups.

Oblique self-assemblies and order-order transitions in polypeptide complexes with PEGylated triple-tail lipids.

We report on highly ordered oblique self-assemblies in ionic complexes of PEGylated triple-tail lipids and cationic polypeptides, as directed by side-chain crystallization, demonstrating also reversible oblique-to-hexagonal order-order transitions upon melting of the side chains. This is achieved in bulk by complexing cationic homopolypeptides, poly-l-lysine (PLys), poly-l-arginine (PArg), and poly-l-histidine (PHis), in stoichiometric amounts with anionic lipids incorporating two hydrophobic alkyl tails and one hydrophilic polyethylene glycol (PEG) tail in a star-shaped A(2)B geometry. Based on Fourier transform infrared spectroscopy (FTIR), the PLys and PArg complexes fold into α-helical conformation.