Microbial medium chainlength poly[(R)-3-hydroxyalkanoate] shows liquid crystal behaviour.
Medium chainlength (mcl) polyhydroxyalkanoates (PHAs) are a class of polymers receiving attention because of their potential as renewable, biodegradable and high tech properties. Unlike most short chain PHAs, mcl-PHAs are low crystallinity and elastomeric in character. In this paper we wish to point out that in their broad properties mcl-PHAs might be classified as thermotropic liquid crystals with dynamic conformational disorder and long range orientational order. As the characterization of mcl-PHAs progresses, their similarities to liquid crystalline elastomers are noteworthy. Wunderlich coined the acronym CONDIS from the words "conformational disorder" to categorize this type of liquid crystal. Thermal analysis reveals a T(g) of -40 to -45°C with several T(m) peaks. The chemistry of the elastomer from (13)C NMR confirms the poly(3-hydroxynonanoate), PHN, composition of the starting material along with two other samples containing double bonds: PHNU-18 and PHNU-31 where the numeral stands for the percent of double bonds.
Department of Chemistry, McGill University, 3420 University Street, Pulp & Paper Research Centre, Montreal, QC H3A 2A7, Canada. robert.marchessault@mcgill.ca
Robert H
RH
Marchessault
Hongyan
H
Dou
Juliana
J
Ramsay
D002152:Calorimetry, Differential Scanning; D050866:Liquid Crystals / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008859:Microscopy, Polarization; D008968:Molecular Conformation; D011091:Polyesters / Q000737:chemistry*; D016958:Pseudomonas putida / Q000737:chemistry*; D013696:Temperature; D014961:X-Ray Diffraction
D011091:Polyesters; C400741:poly(3-hydroxynonanoate)