0000000000139984
AUTHOR
Dwight S. Seferos
Synthesis of gold nanotubes with variable wall thicknesses
We report the synthesis of gold nanotubes with variable wall thicknesses that is accomplished by the deposition of sacrificial hydrophobic polymer cores followed by gold shells within an anodic aluminum oxide template. We demonstrate that by varying polymer core hydrophobicity, the resulting gold shell thickness can be varied. There are two requirements for gold shell formation: (1) the polymer core must be able to be electrodeposited into a tubular (as opposed to wire-like) structure, and (2) the polymer must be hydrophobic, such that it collapses upon exposure to an aqueous solution. An array of gold nanotubes has variable plasmonic properties and can function as a surface enhanced Raman …
What Limits the Molecular Weight and Controlled Synthesis of Poly(3-alkyltellurophene)s?
Polytellurophenes are an emerging class of conjugated polymers; however, their controlled polymerization leading to high molecular weight materials has been a major challenge. Here we present a systematic investigation of the synthesis of poly(3-alkyltellurophene)s using the catalyst transfer polycondensation methodology. Learning that previous syntheses were limited by both polymerization reaction kinetics and polymer solubility, we design new tellurophene monomers to overcome these limitations. Controlled polymerization behavior up to Mn = 25 kDa, chain extension, block copolymerization, external initiation, and well-defined end groups are demonstrated for poly(3-alkyltellurophene)s with …
Template-synthesized nanostructure morphology influenced by building block structure
We report the synthesis and characterization of a series of nanostructures and determine whether several distinct types of building blocks can be fashioned into linear nanostructures using hard-templates and electrochemical methods. We determine the aspects of molecular structure that influence morphology and propose a mechanism whereby morphology changes as a function of building block. We show how hydrophobic side-chains, such as 3-hexyl and 3-(2-ethyl)hexyl, can be used to prepare nanostructures with a geometry that is different from the shape of the template from which they derive. These nanostructures exhibit collapsed, nonlinear, and nonrigid shapes as observed by SEM and TEM. Hydroph…
Donor–Acceptor Polymers for Electrochemical Supercapacitors: Synthesis, Testing, and Theory
Donor–acceptor polymers can store both a positive and negative charge allowing them to function as both the positive and negative charge storage material in a supercapacitor device, however few have been explored for this application. Here, we describe the synthesis of several donor–acceptor polymers and their electrodeposited polymer electrodes. We use differing molecular structures to examine the effect of electron acceptor concentration and show that device stability can be improved significantly by increasing the acceptor concentration. Further, we provide computational insight into the important chemical requirements for achieving even higher performance supercapacitors based on donor–…