Utjecaj koncentracije oksidansa na strukturu PEDOT vodljivog polimera

undergraduate thesis

• Title (english): The influence of oxidant concentration on structure of PEDOT conducting polymer
• Author: Klara Murgić
• Mentor: Zlata Hrnjak-Murgić (mentor)
• Committee member: Zlata Hrnjak-Murgić (predsjednik povjerenstva)
• Committee member: Zvonimir Katančić (član povjerenstva)
• Committee member: Marijana Kraljić Roković (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2019-09-12, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Elektrovodljivi polimeri su organski spojevi koje karakterizira konjugirana dvostruka veza, te zbog toga uz svojstva koje imaju uobičajeni polimeri, kao što su mala težina, otpornost na koroziju i jeftina izrada, imaju i svojstvo električne vodljivosti. Uz konjugirane veze, za postizanje vodljivosti potrebno je da postoje slobodni nositelji naboja što se postiže oksidacijom ili redukcijom polimera. Elektrovodljivi polimeri su našli primjenu u antikorozivnoj zaštiti, elektrostatičkoj zaštiti uređaja, elektrokromnim uređajima, a u zadnje vrijeme i u području kemijskih senzora i biosenzora. Jedan od najčešće korištenih elektrovodljivih polimera je poli(3,4-etilendioksitiofen) (PEDOT), a dobiva se elektrokemijskom ili kemijskom oksidacijskom polimerizacijom. U radu je sintetiziran PEDOT vodljivi polimer kemijskom oksidacijskom polimerizacijom, uz oksidans amonijev persulfat ((NH4)2S2O8). PEDOT vodljivi polimer pripravljen je uz četiri definirana omjera monomera EDOT-a i oksidansa, 1:1, 1:2, 1:4 i 1:6. Kako bi se potvrdila uspješnost sinteze uzoraka PEDOT polimera, provedena je njihova karakterizacija infracrvenom spektroskopijom s Fourirerovim transformacijama (FTIR). Metodom sonde s četiri točke određena je elektrovodljivost uzoraka, a snimljena je i ciklička voltametrija za sve sintetizirane uzorke PEDOT-a. Termogravimetrijskom analizom (TGA) utvrđena je toplinska postojanost ispitivanih uzoraka. Rezultati su pokazali da se povećanjem omjera monomera i oksidansa smanjuje stupanj polimerizacije i pada elektrovodljivost. Ustanovljeno je da omjeri monomer:oksidans iznad 1:2 negativno utječu na strukturu PEDOT-a. Nadalje, kod uzorka sa omjerom 1:6 dolazi do degradacije polimera uslijed preoksidiranosti PEDOT-a snažnim oksidansom.

Abstract (english)

Conductive polymers are organic compounds characterized by conjugated double bonds, and therefore have the properties of electrical conductivity in addition to those of conventional polymers such as low weight, corrosion resistance and cheap fabrication. In addition to conjugated bonds, to achieve conductivity, it is necessary to have free charge carriers, which is achieved by oxidation or reduction of the polymer. Conductive polymers have been used in corrosion protection, electrostatic protection of devices, electrochromic devices, and more recently in the field of chemical sensors and biosensors. One of the most commonly used conductive polymers is poly(3,4-ethylenedioxythiophene) (PEDOT), which is obtained by electrochemical or chemical oxidation polymerization. In this work PEDOT conductive polymer was synthesized by chemical oxidation polymerization, with the ammonium persulfate ((NH4)2S2O8) oxidant. PEDOT conductive polymer was prepared with four defined ratios of EDOT monomer and oxidant, 1:1, 1:2, 1:4 and 1:6. In order to confirm the successfull the synthesis of PEDOT polymer samples, characterization was performed by infrared spectroscopy with Fourier transformations (FTIR). The four-point probe method was used to determine electrical conductivity of the samples and cyclic voltammetry was recorded for all PEDOT samples. Thermogravimetric analysis (TGA) was used to determine thermal stability of the tested samples. The results showed that by increasing the ratio of monomers to oxidants, the degree of polymerization decreases and the conductivity reduces. It has been found that monomer: oxidant ratios above 1:2 adversely affect the structure of PEDOT. Furthermore, a sample with a ratio of 1:6 degrades the polymer due to the overoxidation of PEDOT with a strong oxidant.

• Keywords: elektrovodljivi polimeri; poli(3 4-etilendioksitiofen); kemijska oksidacijska polimerizacija; ciklička voltametrija
• Keywords (english): conductive polymers; poly (3 4-ethylenedioxythiophene); chemical oxidation polymerization; cyclic voltammetry
• Language: croatian
• URN:NBN: urn:nbn:hr:149:867106
• Study programme: Title: Materials Science and Engineering - Undergraduate study; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka kemijskog inženjerstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2023-05-26 09:50:42