Thesis

The development of novel electrochemically deposited polymers for sensing applications

Creator
Rights statement
Awarding institution
  • University of Strathclyde
Date of award
  • 2013
Thesis identifier
  • T13488
Qualification Level
Qualification Name
Department, School or Faculty
Abstract
  • The development of sensors capable of detecting explosives is an important task needed to protect citizens and infrastructure. The success of such sensors requires progress in materials chemistry and transducer technology to deliver compact, low-cost, stand-alone devices that can be widely deployed. Interdigitated electrodes (IDEs) are viewed as a ubiquitous and low-cost platform for delivering this type of sensor technology. IDEs can be transformed into chemical sensors by depositing or growing sensing materials whose material properties are modified in the presence of the target chemicals. Organic semiconductors offer unique characteristics such as tunability of electronic properties via chemical synthesis, compatibility with mechanically flexible substrates, low-cost manufacturing, and tailoring to attain specific chemical and biological functionalities. The concept of combining such functional organic semiconductor films with IDEs presents a technically and economically viable route to sensors having low power consumption, high sensitivity and selectivity to target molecules, reversibility and finally affordability. Chapter 1 summarizes an overview of polymeric sensors, state of the art of explosive detection and current progress in porous polymeric materials. Chapter 2 describes the chemical synthesis of novel monomers based on ProDOT (1,3-propylenedioxythiophene) and bisalkylsulfanyl-terthiophenes. These polymers are halogen-functionalised to be selectively sensitive towards nitrocontaining compounds related to explosives such as TNT or DNT, based on the halogen-nitro association. The key feature in this work is the localised electropolymerisation of the synthesised monomers directly onto the device; an inexpensive and fast fabrication method. The development of a suitable testing system, sensor fabrication and its performance are described in Chapter 3. These sensors have been tested under controlled conditions for their sensitivity to vapours of nitro-bearing compounds, and also a range of other volatile chemicals commonly found in the atmosphere. Vapours of 1-nitropropane, nitrobenzene and 2-nitrotoluene were used in sensor testing as proxies for nitro vapours, which are also present in explosives. Chapter 4 summarizes the synthesis of new materials, which will provide cross-linked polymers with high porosity and enhanced surface area, thus enhancing the sensitivity and response speed of the previously electrochemically polymerised thin films. The large surface area over volume of such porous films is expected to greatly increase the sensitivity and significantly reduce response times of the sensors.
Resource Type
DOI
Date Created
  • 2013
Former identifier
  • 991508

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