Langmuir−Blodgett Films of Conducting Diblock Copolymers

Abstract

Novel amphiphilic block copolymers have been synthesized via ring-opening metathesis polymerization (ROMP), where one block is a precursor to a water-soluble polymer and the other block is a precursor to polyacetylene. The water-soluble block is made from a silyl ester protected carboxylic acid functionalized polymer. The silyl ester groups are used to protect the ROMP initiator from the carboxylic acid groups during polymerization and are easily deprotected afterward. The polyacetylene precursor block is made via ROMP using an approach known as the "Durham" route to polyacetylene. These amphiphilic block copolymers are surface active and quite amenable to the Langmuir-Blodgett (LB) technique, whereby films of these materials were fabricated and converted to polyacetylene-containing films by heating. UVvisible spectroscopy showed that the polyacetylene chains are oriented mostly in the plane of the LB film and in the dipping direction of the substrate. Upon doping with iodine, these films were shown to have better conductivities than either spin-coated or bulk cast films made from the same materials. The higher conductivity is explained by the high degree of order imparted using the LB technique.

Synthesis and characterization of ZnO nanostructures templated using diblock copolymers

“…In our work, the templating is markedly different from previous work in that the metal salt is introduced while the polymer is in solution, before any microphase separation of the two blocks can occur. Earlier block copolymer nanoreactor synthesis schemes1, 5, 12, 14 introduced the metal salt by diffusion of a metal salt solution into a spin‐cast or static‐cast microphase‐separated solid film. The advantages which our templating process presents are a rapid diffusion and attachment of the metal to the second (minority) polymer since both are in the liquid state and resulted in more uniform self‐assembled nanostructures at room temperature through wet chemical methods, thus making it an appropriate process to integrate with current and future semiconductor processing technology, without additional thermal cycling steps.…”

“…Based on the chosen volume fractions of the two blocks of the copolymer, a spherical nanoparticle morphology was targeted in this work. NORCOOH was synthesized and capped with trimethylsilane (TMS) similarly to literature procedures 14. The polymer synthesis took place in an inert atmosphere in an MBraun Labmaster glove box.…”

Accelerated Ring-Opening Metathesis Polymerization of a Secondary Amide of 1-Cyclobutene by Hydrogen-Bonding Interaction

“…Ring-opening metathesis polymerization (ROMP) has attracted a great deal of attention because it provides a versatile method for the synthesis of functional polymers such as hydrogels, biologically active polymers, and liquid crystalline polymers . This versatility has been mainly driven by the remarkable development of well-defined transition-metal catalysts on the basis of W, Mo, and Ru complexes, which readily polymerize many strained cycloalkenes such as norbornene derivatives, cyclobutene, cyclooctene, and dicyclopentadiene .…”

Controlled Room Temperature Synthesis of CoFe2O4 Nanoparticles through a Block Copolymer Nanoreactor Route

“…Norbornene (NOR), anhydrous tetrahydrofuran (THF), and dichloromethane (CH 2 Cl 2 ) were purchased from Aldrich and were used without any further purification. NORCOOH (2-norbornene-5,6,-dicarboxylic acid) and NORCOOTMS (2-norbornene-5,6,-dicarboxylic acid bis(trimethylsilyl) ester) were prepared according to literature procedures . A Grubbs catalyst (bis(tricyclohexylphosphine)benzylidineruthenium(IV) dichloride) for the polymerization was purchased from Strem Chemicals.…”

“…NORCOOH (2norbornene-5,6,-dicarboxylic acid) and NORCOOTMS (2-norbornene-5,6,-dicarboxylic acid bis(trimethylsilyl) ester) were prepared according to literature procedures. 8 A Grubbs catalyst (bis(tricyclohexylphosphine)benzylidineruthenium(IV) dichloride) for the polymerization was purchased from Strem Chemicals. Stock solutions (30 mg/mL) of the catalyst was prepared by dissolving the catalyst in THF and CH 2Cl2.…”