title: Responsive organogels formed by supramolecular self assembly of PEG-block-allyl-functionalized racemic polypeptides into β-sheet-driven polymeric ribbons.
abstract: A chemically reactive hybrid diblock polypeptide gelator poly(ethylene glycol)-block-poly(dl-allylglycine) (PEG-b-PDLAG) is an exceptional material, due to the characteristics of thermo-reversible organogel formation driven by the combination of a hydrophilic polymer chain linked to a racemic oligomeric homopeptide segment in a range of organic solvents. One-dimensional stacking of the block copolymers is demonstrated by ATR-FTIR spectroscopy, wide-angle X-ray scattering to be driven by the supramolecular assembly of β-sheets in peptide blocks to afford well-defined fiber-like structures, resulting in gelation. These supramolecular interactions are sufficiently strong to achieve ultra low critical gelation concentrations (ca. 0.1 wt%) inN,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and methanol. The critical gel transition temperature was directly proportional to the polymer concentration, so that at low concentrations, thermoreversibility of gelation was observed. Dynamic mechanical analysis studies were employed to determine the organogel mechanical properties, having storage moduli ofca. 15.1 kPa at room temperature.
authors: Departments of Chemistry and Chemical Engineering, Texas A&M University, P.O. BOX 30012, 3255 TAMU, College Station, TX 77842, USA.
authors: Jiong
authors: J
authors: Zou
authors: Departments of Chemistry and Chemical Engineering, Texas A&M University, P.O. BOX 30012, 3255 TAMU, College Station, TX 77842, USA.
authors: Fuwu
authors: F
authors: Zhang
authors: Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, USA.
authors: Yingchao
authors: Y
authors: Chen
authors: Departments of Chemistry and Chemical Engineering, Texas A&M University, P.O. BOX 30012, 3255 TAMU, College Station, TX 77842, USA.
authors: Jeffery E
authors: JE
authors: Raymond
authors: Departments of Chemistry and Chemical Engineering, Texas A&M University, P.O. BOX 30012, 3255 TAMU, College Station, TX 77842, USA ; Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri, 63130, USA.
authors: Shiyi
authors: S
authors: Zhang
authors: Departments of Chemistry and Chemical Engineering, Texas A&M University, P.O. BOX 30012, 3255 TAMU, College Station, TX 77842, USA.
authors: Jingwei
authors: J
authors: Fan
authors: Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, USA.
authors: Jiahua
authors: J
authors: Zhu
authors: Departments of Chemistry and Chemical Engineering, Texas A&M University, P.O. BOX 30012, 3255 TAMU, College Station, TX 77842, USA.
authors: Ang
authors: A
authors: Li
authors: Departments of Chemistry and Chemical Engineering, Texas A&M University, P.O. BOX 30012, 3255 TAMU, College Station, TX 77842, USA.
authors: Kellie
authors: K
authors: Seetho
authors: Departments of Chemistry and Chemical Engineering, Texas A&M University, P.O. BOX 30012, 3255 TAMU, College Station, TX 77842, USA.
authors: Xun
authors: X
authors: He
authors: Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, USA.
authors: Darrin J
authors: DJ
authors: Pochan
authors: Departments of Chemistry and Chemical Engineering, Texas A&M University, P.O. BOX 30012, 3255 TAMU, College Station, TX 77842, USA.
authors: Karen L
authors: KL
authors: Wooley