Nanostrukture polianilina sintetisane oksidativnom polimerizacijom anilina u sistemima bez dodatka kiseline

Abstract

Istraživanja u ovoj doktorskoj disertaciji obuhvataju: sinteze nanostruktura polianilina (PANI) oksidativnom hemijskom polimerizacijom anilina (ANI) sa amonijum peroksidisulfatom (APS) u razliĉitim sistemima bez dodatka kiseline i templata, u uslovima opadajućeg pH, karakterizaciju sintetisanih PANI razliĉitim fiziĉkohemijskim metodama i prouĉavanje mehanizma sinteze i formiranja PANI nanostruktura u ispitivanim sistemima. Sinteze PANI su uraĊene korišćenjem jednostavnih, ekonomiĉnih i ekološki prihvatljivih procedura i supstancija. Akcenat je bio na korišćenju što manjeg broja hemikalija za odgovarajuće sintetiĉke procedure. Pored oksidacionog sredstva (APS) i monomera (ANI), u reakcione sisteme su ukljuĉeni razliĉiti organski rastvaraĉi, hidrolizovani kolagen (biološki materijal), ili FeSO4 (katalizator). Idealan molski odnos APS i ANI od 1,25 za sintezu elektroprovodnog oblika PANI, emeraldin soli, je upotrebljen u svim sintezama. Varirani su sledeći uslovi: poĉetna pH vrednost, dužina trajanja sinteze, uslovi mešanja reakcione smeše i organski rastvaraĉi. Rezultati dobijeni u okviru ove doktroske teze se mogu podeliti u sledećih pet celina: 1) Oksidacija ANI vršena je pomoću APS u sistemima bez dodatka kiseline i templata u kojima su koncentracije oba reaktanta bile niske (CANI = 0,02 i 0,05 M). Reakcija je praćena merenjem temperature i pH. Karakteristike polimerizacije i sintetisanih PANI uporeĊivane su sa analognim sintezama u koncentrovanim sistemima (CANI = 0,1 i 0,2 M). Skenirajućom elektronskom mikroskopijom (SEM) je utvrĊeno da se nanostrukturni PANI sulfat/hidrogen sulfat, sintetisan pri niskim koncentracijama reaktanata, sastoji od mreže nanoštapića i nanogranula. Molekulska struktura sintetisanih i dedopiranih PANI uzoraka, ispitivana elementarnom analizom, infracrvenom spektroskopijom sa furijeovom transformacijom (FTIR), ramanskom, ultraljubiĉastom-vidljivom (UV-Vis) i elektronskom paramagnetnom rezonantnom (EPR) spektroskopijom, je znaĉajno drugaĉija u poreĊenju sa molekulskom strukturom nanostrukturnih PANI sulfata/hidrogen sulfata sintetisanih u koncentrovanim...

The research in this Ph.D. thesis includes: synthesis of nanostructured polyaniline (PANI) by the chemical oxidative polymerization of aniline (ANI) with ammonium peroxydisulfate (APS) in different systems with the use of dopant-free template-free falling-pH method, characterization of the synthesized PANI by various physicochemical methods and the study of the mechanism of synthesis and the formation of PANI nanostructures in investigated systems. Syntheses of PANI were performed using simple, cost-effective and environmentally friendly procedures and substances. The emphasis was on using not as many chemicals for the proper synthetic procedure. Besides the oxidant (APS) and monomer (ANI), in the reaction mixtures were included various organic solvents, hydrolyzed collagen (a biological system) or FeSO4 (catalysator). The optimal molar ratio of the ANI and APS of 1.25 for the electroconductive emeraldin salt form of PANI syntheses was used in all synthetic procedures. The initial pH value, the length of the synthesis, stirring conditions of the reaction mixture and the organic solvents were varied. The results obtained within this thesis can be divided into the following five sections: 1) The oxidation of ANI with APS was conducted in diluted aqueous systems (CANI = 0,02 i 0,05 M) without added acid and template (dilute dopant-free template-free method). The reaction was monitored by measuring the temperature and pH. The characteristics of the polymerization and the synthesized PANI were compared to analog synthesis in concentrated systems (CANI = 0,1 i 0,2 M). Scanning electron microscopy (SEM) revealed that nanostructured PANI sulfate/hydrogen sulfate, synthesized in low concentration conditions, consists of a network of nanorods and nanogranules.The molecular structure of PANI sulfate/hydrogen sulfate prepared in diluted ANI solutions considerably different in comparison to the structure of PANI sulfate/hydrogen sulfate prepared in concentrated aqueous ANI was discovered by elemental analysis, Fourier transform infrared spectroscopic (FTIR), Raman, ultra-violet (UV–Vis) and electron paramagnetic resonance (EPR) spectroscopic studies. The...