Liquid Crystal Formation Coupled with the Coil−Helix Transition in the Ternary System Poly(γ-benzyll-glutamate)/Dichloroacetic Acid/Dichloroethane

Abstract

Phase behavior and ordering characteristics were reported for poly(γ-benzyl l-glutamate) (PBLG) in a mixed solvent containing a denaturant acid, dichloroacetic acid (DCA), + dichloroethane (DCE). The solutions of PBLG prepared so as to be liquid crystal at room temperature were observed to undergo a reentrant isotropic transition at low temperature where conformational disordering of PBLG molecules takes place. The deuterium quadrupolar splitting data obtained by the 2H NMR method were analyzed to elucidate the conformation and orientational order parameter of the α-helix in the liquid crystalline phase. The conformation of PBLG molecules in the isotropic state was estimated from the observed 13C NMR chemical shift. The molecular information gained through these experiments was implemented into the theoretical expression set forth by Flory and Matheson. The phase diagrams calculated on this basis have been compared with those observed. The theory has provided a reasonable picture for the high- and low-temperature phase transitions of the PBLG/DCA/DCE system.

Drug releasing behavior of hybrid micelles containing polypeptide triblock copolymer

“…Poly(g-benzyl-L-glutamate)-b-poly(propylene oxide)-b-poly(g-benzyl-L-glutamate) (PBLG-b-PPO-b-PBLG) triblock copolymers were synthesized by ring-opening polymerization of g-benzyl-L-glutamate-N-carboxyanhydride (BLG-NCA) initiated by NH 2 -PPO-NH 2 [46][47][48]. NH 2 -PPO-NH 2 (0.2 g; 0.05 mmol) and BLG-NCA (2.7 g; 10 mmol) was dissolved in dioxane separately in two flame-dried reaction bottles, then, BLG-NCA solution was added to the solution of NH 2 -PPO-NH 2 via a transfer cannula.…”

Structure and Performance of Poly(vinyl alcohol)/Poly(γ-benzylL-glutamate) Blend Membranes

“…Synthesis of Polypeptide Homopolymer PBLG homopolymer was prepared by a standard N-carboxyl-c-benzyl-Lglutamate anhydride (NCA) method [31,32]. The molecular weight of the PBLG homopolymer was estimated from the [g] value measured in dichloroacetic acid (DCA), according to the document [33].…”

Effects of reaction conditions on the grafting percentage of poly(ethylene glycol)-block-poly(γ-benzyl L-glutamate)-graft-poly(ethylene glycol) copolymer

“…[17][18][19] The molecular weight of PBLG was estimated from the intrinsic viscosity measured in dichloroacetic acid (DCA). 24 The molecular weight of PBLG homopolymer used in the study is 50000.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12] Because of the unique structures and properties, synthesized polypeptides and their copolymers have been investigated widely in the fields of protein simulation, macromolecular conformational study, catalysis, drug delivery, nanoreactors etc. [13][14][15][16][17][18][19][20][21][22][23] Recently, much interest has been focused on the self-association behavior of the copolymers composed of hydrophobic polypeptide segments and hydrophilic polymer chains. 1,[7][8][9][10][11][12][13] Cho et al 9 have reported the formation of polymeric micelles composed of poly(γ-benzyl L-glutamate) and poly(ethylene oxide) in aqueous medium and the drug delivery system based on the core-shell nanoparticles with PBLG as the hydrophobic inner core and PEO as the hydrophilic outer shell.…”