resumo
In this study, lignosulfonate (LS) from the acid sulfite pulping of eucalypt wood was used to synthesize LS-based polyurethanes (PUs) doped with multiwalled carbon nanotubes (MWCNTs) within the range of 0.1-1.4% w/w, yielding a unique conducting copolymer composite, which was employed as a sensitive material for all-solid-state potentiometric chemical sensors. LS-based PUs doped with 1.0% w/w MWCNTs exhibited relevant electrical conductivity suitable for sensor applications. The LS-based potentiometric sensor displayed a near-Nernstian or super-Nernstian response to a wide range of transition metals, including Cu(II), Zn(II), Cd(II), Cr(III), Cr(VI), Hg(II), and Ag(I) at pH 7 and Cr(VI) at pH 2. It also exhibited a redox response to the Fe(II)/(III) redox pair at pH 2. Unlike other lignin-based potentiometric sensors in similar composite materials, this LS-based flexible polymeric membrane did not show irreversible complexation with Hg(II). Only a weak response toward ionic liquids, [C(2)mim]Cl and ChCl, was registered. Unlike LS-based composites comprising MWCNTs, those doped with graphene oxide (GO), reduced GO (rGO), and graphite (Gr) did not reveal the same electrical conductivity, even with loads up to 10% (w/w), in the polymer composite. This fact is associated, at least partially, with the different filler dispersion abilities within the polymeric matrix.
palavras-chave
ION-SELECTIVE ELECTRODES; HEAVY-METAL IONS; POTENTIOMETRIC SENSORS; DIELECTRIC-PROPERTIES; THERMAL-PROPERTIES; CARBON NANOTUBES; CHEMICAL SENSORS; SCHIFF-BASE; LIGNIN; COMPOSITES
categoria
Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter
autores
Magina, S; Rudnitskaya, A; Soreto, S; Costa, LC; Barros-Timmons, A; Evtuguin, DV
nossos autores
Ana Margarida Madeira Viegas de Barros Timmons
Professor associado
Dmitry Evtyugin
Professor Associado com Agregação
Sandra Pereira Magina
Investigadoragradecimentos
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 and UIDP/50011/2020, CESAM, UIDP/50017/2020 and UIDB/50017/2020, and i3N, UIDB/50025/2020 and UIDP/50025/2020, financed by national funds through the Portuguese Foundation for Science and Technology (FCT)/Ministry of Science, Technology and Higher Education (MCTES) and was funded by FCT and the European Social Fund (ESF) within the framework of PORTUGAL2020, namely, through the Programa Operacional Regional do Centro (Centro 2020) (PhD grant SFRH/BD/121275/2016).