Synthesis and characterization of intrinsically stretchable and healable conducting graft copolymer PEDOT-g-PCL

U posljednja četiri desetljeća, otkako su otkriveni, elektrovodljivi polimeri privlače pažnju znanstvenika i inženjera u cijelom svijetu. To su materijali koji kombiniraju svojstva polimernih materijala s električnom provodljivošću te se odlikuju dobrom kemijskom stabilnosti, otpornosti na koroziju, biokompatibilnosti i jednostavnom obradom. Zbog izuzetno dobrih svojstava našli su primjenu u laganim i punjivim baterijama, diodama koje emitiraju svjetlost, elektrokromnim uređajima, senzorima, molekularnoj elektronici. PEDOT, poli(3,4-etilendioksitiofen) je jedan od najpoznatijih elektrovodljivih polimera koji se često koristi za različite primjene. Nedostatak rastezljivih i samozacjeljujućih svojstava kod PEDOTA onemogućuje njegovu primjenu u nosivoj elektronici. Spomenuta svojstva se mogu poboljšati sintezom kopolimera posebnih karakteristika, cijepljenjem PEDOT-a s fleksibilnim bočnim granama radikalskom polimerizacijom prijenosom atoma (ATRP). Cilj rada je sintetizirati graft kopolimer PEDOT-g-PCL s dvije različite vrste PCL-a (PPA-PCL i HEMA-PCL). Sinteza se provodila u četiri koraka, s tim da se u prvom koraku sintetizirao monomer 2-(tiofen-3-il) etil 2-bromo-2-metilpropanoat (ThBr), a u drugom makroinicijator PEDOT-Br. Treći korak je bio sinteza graft kopolimera PEDOT-g-PCL ATRP-om. Karakterizacija dobivenih uzoraka provedena je infracrvenom spektroskopijom s Fourierovom transformacijom (FTIR), nuklearnom magnetskom rezonancijom (NMR), termogravimetrijskom analizom (TGA). Od sintetiziranog graft kopolimera pripremljena je tinta za inkjet ispis na poliuretansku (PU) podlogu. Elektrovodljivost ispisanog sloja na podlozi je određena metodom sondi s 4 točke. Rezultati metoda FTIR i NMR dokazali su uspješnu sintezu produkata, a TG analizom određena je toplinska stabilnost sintetiziranih produkata. Temperatura početka razgradnje veća je kod sintetiziranog graft kopolimera PEDOT-g-PCL nego kod makroinicijatora PEDOT-Br, što znači da se poboljšalo svojstvo toplinske stabilnosti. Dobiveni graft kopolimer je vodljiv i spada u rang poluvodiča.Since its discovery nearly four decades ago, electrically conductive polymers have captured the interest of researchers and engineers all around the world. These materials have strong chemical stability, corrosion resistance, biocompatibility, and easy processing. They combine the features of polymer materials with electrical conductivity. Due to their outstanding properties, they have been applied to molecular electronics, light-emitting diodes, electrochromic devices, sensors, and rechargeable batteries. One of the most well-known electroconductive polymers, PEDOT, or poly (3,4-ethylenedioxythiophene), is frequently utilized for a variety of applications. However, PEDOT's lack of elasticity and regeneration capabilities prevents its use in wearable electronics. By developing copolymers with unique qualities and grafting flexible side branches onto PEDOT using atom transfer radical polymerization (ATRP), previously mentioned properties can be improved. The aim of the project is to synthesize the graft copolymer PEDOT-g-PCL using two different types of PCL, PPA-PCL and HEMA-PCL. The four-step synthesis starts with the synthesis of the monomer 2-(thiophen-3-yl) ethyl 2-bromo-2-methylpropanoate (ThBr), followed by the synthesis of the second macroinitiator, PEDOT-Br. The third step entailed the ATRP's synthesis of the PEDOT-g-PCL graft copolymer. Nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR) were used to characterize the obtained materials. The synthesized graft copolymer was used to create an ink for inkjet printing on a polyurethane (PU) substrate. The 4-point probe approach was used to determine the printed layer's electrical conductivity on the substrate. The products' successful synthesis was demonstrated by the findings of the FTIR and NMR techniques, and the TG analysis was used to determine the products' thermal stability. The synthesized PEDOT-g-PCL graft copolymer has increased thermal stability since the decomposition onset temperature is greater than that of the PEDOT-Br macroinitiator. The resulting graft copolymer is conductive and belongs to the category of semiconductors