| Abstract | Cilj ovog rada bila je elektrokemijska sinteza i ispitivanje slojeva poli(3,4- etilendioksitiofen) (PEDOT), te kompozita PEDOT/grafen na Pt disk elektrodi. Raslojavanje grafita i sinteza grafena provedena je polarizacijom grafitnog štapića u otopini natrijeva dodecilsulfata (SDS). Uzorak grafena izoliran iz suspenzija ispitan je Ramanovom spektroskopijom pri čemu je utvrđeno da je dobiveni uzorak grafenov oksid (GO). Metode korištene za sintezu bile su su: ciklička voltametrija, kronoamperometrija i kronopotenciometrija. Kod cikličke voltametrije sinteza je provedena u području potencijala od -0,5 V do 0,9 V, 1,0 V ili 1,2 V. Broj ciklusa sinteze je također bila jedna od varijabli koja se mijenjala tijekom sinteze, a provedeno je 5, 10 i 20 ciklusa. Kronoamperometrijska sinteza provodila se kod potencijala 0,8 V, 0,9 V, 1,0 V i 1,1 V u trajanju od 60 sekundi. Metodom kronopotenciometrije sinteza je provedena sa strujama koje su iznosile 0,05 mA i 0,025 mA tijekom 120 sekundi. Sinteza je provedena iz 0,01 mol dm^-3 i 0,03 mol dm^-3 3,4-etilendioksitiofen (EDOT) u 0,1 mol dm^-3 otopini površinski aktivnih tvari, SDS ili natrijeva dodecilbenzensulfonata (SDBS). Nakon sinteze sloj kompozita je polariziran pri -1 V kako bi se ugrađeni GO reducirao. Svojstva PEDOT sloja i kompozita ispitana su metodama cikličke voltametrije i kvarc kristalne nanovage (QCNB) u otopinama SDS i SDBS te 0,5 mol dm^-3 otopini KCl. Sinteza PEDOT sloja i kompozita PEDOT/grafen provedena je uspješno. Najbolja elektrokemijska svojstva pokazao je PEDOT10-2 sloj dobiveni metodom cikličke voltametrije uz konačni potencijala 1,0 V i uz 20 ciklusa sinteze pa je pri tim uvjetima provedena sinteza kompozita. Različiti odzivi zabilježeni tijekom sinteze PEDOT sloja i kompozitnog sloja ukazuju da se GO ugradio u strukturu vodljivog polimera. Redukcijom kompozita kod -1 V poboljšala su se kapacitivna svojstva pa se pretpostavlja da je u navedenom procesu došlo do redukcije GO. |
| Abstract (english) | The objective of this research was the electrochemical synthesis and testing of poly (3,4-ethylenedioxythiophene), (PEDOT) and PEDOT/grafen composite on the Pt disc electrode. Graphite exfoliation and graphene synthesis was performed by polarization of graphite rod in sodium dodecyl sulfate solution (SDS). The graphene sample isolated from the suspension was characterised by Raman spectroscopy which showed that the obtained sample was graphene oxide (GO). The syntheses were carried out by using cyclic voltammetry, chromoamperometry and chronopotensometry methods. By using cyclic voltammetry the synthesis was carried out in the potential range from -0.5 V to 0.9 V, 1.0 V or 1.2 V with 5, 10 and 20 number of cycles. Chronoamperometry was performed at 0.8 V, 0.9 V 1.0 V and 1.1 V during 60 seconds. The chronopotensometry was performed with currents ranging from 0.05 mA to 0.025 mA during 120 seconds. Synthesis was carried out by using 0.01 mol dm^-3 and 0.03 mol dm^-3 3,4-ethylenedioxythiophene (EDOT) in 0.1 mol dm^-3 surfactant solution, SDS or sodium dodecylbenzene sulfonate (SDBS). After the synthesis the composite layer was polarized at -1 V in order to reduce GO intercalated within the polymer. Properties of PEDOT layer and the composite layer were tested by mean of cyclic voltammetry and quartz crystal nanobalance (QCNB) in solutions of SDS or SDBS and 0.5 mol dm^-3 KCl solution. The synthesis of PEDOT and composite PEDOT/grafen was successfully performed. PEDOT10-2 layer obtained by the cyclic voltammetry method with a final potential of 1.0 V and with 20 cycles of synthesis showed the the best electrochemical properties and therefore this procedure was chosen to prepare composite layer. Different electrochemical responses observed during the PEDOT and composite layer synthesis indicate that GO is intercalated within the conductive polymer structure. By reducing the composite layer at -1 V, the capacitance properties were improved and therefore it is assumed that GO was reduced during negative polarisation process. |
