title: Smectic ordering in solutions and films of a rod-like polymer owing to monodispersity of chain length.
abstract: Solutions and melts of stiff ('rod-like') macromolecules often exhibit nematic liquid crystalline phases characterized by orientational, but not positional, molecular order. Smectic phases, in which macromolecular rods are organized into layers roughly perpendicular to the direction of molecular orientation, are rare, owing at least in part to the polydisperse nature (distribution of chain lengths) of polymers prepared by conventional polymerization processes. Bacterial methods for polypeptide synthesis, in which artificial genes encoding the polymer are expressed in bacterial vectors, offer the opportunity to make macromolecules with very well defined chain lengths. Here we show that a monodisperse derivative of poly(gamma-benzyl alpha,L-glutamate) prepared in this way shows smectic ordering in solution and in films. This result suggests that methods for preparing monodisperse polymers might provide access to new smectic phases with layer spacings that are susceptible to precise control on the scale of tens of nanometres.
authors.affiliation: Polymer Science and Engineering Department, University of Massachusetts, Amherst 01003, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Yu
authors.forename: V P
authors.initials: VP
authors.lastname: Conticello
authors.forename: G
authors.initials: G
authors.lastname: Zhang
authors.forename: C
authors.initials: C
authors.lastname: Kayser
authors.forename: M J
authors.initials: MJ
authors.lastname: Fournier
authors.forename: T L
authors.initials: TL
authors.lastname: Mason
authors.forename: D A
authors.initials: DA
authors.lastname: Tirrell
mesh_terms: D018441:Biofilms; D001704:Biopolymers; D002725:Chloroform; D004146:Dioxanes; D004926:Escherichia coli; D009682:Magnetic Resonance Spectroscopy; D011099:Polyglutamic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D014269:Trifluoroacetic Acid; D014961:X-Ray Diffraction
chemical_list: D001704:Biopolymers; D004146:Dioxanes; D011993:Recombinant Fusion Proteins; D012996:Solutions; C003172:poly-gamma-benzyl-L-glutamate; D011099:Polyglutamic Acid; D002725:Chloroform; D014269:Trifluoroacetic Acid; C025223:1,4-dioxane