Electrokinetic and antibacterial properties of needle like‐TiO₂/polyrhodanine core/shell hybrid nanostructures

Abstract

The aim of this study was to fabricate needle like-TiO 2 /polyrhodanine nanostructures by polymerizing rhodanine monomer on the TiO 2 nanoparticles' surfaces and investigate their antibacterial activities. The structural, thermal, morphological, surface and electrical properties of non-covalently functionalized nanoparticles were characterized by using FTIR, XPS, elemental analysis, TGA, XRD, SEM-EDX, TEM, contact angle, and conductivity measurements. Characterization results confirmed the formation of needle like-TiO 2 /polyrhodanine (PRh) core/shell hybrid nanostructures. Alterations on the surface and electrokinetic properties of the materials were characterized by zeta (f)-potential measurements with the presence of various salts and surfactants. The f-potential of needle like-TiO 2 was observed to increase from 27.6 mV to 128.4 mV after forming a core/shell needle like-TiO 2 /PRh nanocomposite structure and with the presence of cetyltrimethyl ammonium bromide (CTAB) surfactant. Thereby colloidally more stable dispersions were formed. Antibacterial properties of needle like-TiO 2 /PRh were also tested against Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli by various methods and they showed good antibacterial activity. The highest killing efficiency was determined for needle like-TiO 2 /PRh against E. coli by colony-counting method as 0.95. TEM experiments also showed the immobilizations of the nanoparticles on E. coli and revealed the interactions between E. coli and the nanoparticles.

Graphene oxide/rhodanine redox chemistry and its application in designing high-performance elastomer/graphene composites

“…26 Moreover, the characteristic peaks of other oxygen-containing groups, such as carboxy (C-O, 1401 cm À1 ), epoxy (C-O-C, 1227 cm À1 and 971 cm À1 ) and alkoxy (C-O, 1057 cm À1 ) groups, can also be identied in the spectrum of GO. 16,30 TGA results showed that the chemical reduction of GO by rhodanine is effective at improving the thermal stability of RGO despite the existence of adsorbed organics (polyrhodanine), which supports the successful conversion of GO into RGO. In addition, new bands at 1567 and 1485 cm À1 , corresponding to C]C stretching modes, and the characteristic absorption at approximately 1158 cm À1 , which is attributed to the C-C stretching mode, appear.…”

“…37 Compared with GO, the D and G bands of RGO are red shied to 1330 cm À1 and 1564 cm À1 , respectively, possibly because of the restored conjugated structure of graphene. 30 Based on the FTIR spectra, the oxidative polymerization of rhodanine induced by GO can be proposed to proceed via the coupling of carbon and nitrogen atoms by forming C]C, C]N, and C-O bonds. 39 The intensity ratio of the D and G bands (I D /I G ), which represents the ratio of disordered and ordered carbon structures, is oen adopted to evaluate the defects in graphene and monitor the its functionalization.…”

Enhanced dielectric and electrorheological properties of needle‐like TiO2/polyrhodanine core/shell hybrid nanostructure

“…Facile synthesis of core/shell structured rutile type needle‐like TiO 2 /polyrhodanine nanocomposite was carried out by using FeCl 3 as the oxidant and taking the mole ratio of TiO 2 :FeCl 3 as 1:1. Full details of the reaction procedure, all the characterization data and antibacterial properties were given in our previous publication . The homogeneously distributed shell thickness of PRh chains on the surfaces of needle‐like TiO 2 was between 4.8–6.5 nm and the conductivity of needle‐like TiO 2 /PRh nanocomposite was 1.8 × 10 −5 S cm −1 …”

“…TiO 2 is also an important material from technical point of view and it has three crystalline structures namely anatase, rutile and brookite. While the crystalline structure of anatase and rutyl is tetragonal, brookite has orthorhombic . These unique properties of TiO 2 can be improved by altering the surface chemistry of TiO 2 nanoparticles by various surface functionalization techniques by applying bottom‐up or up‐bottom engineering strategy …”

“…In this study, ER properties of needle‐like TiO 2 and needle‐like TiO 2 /PRh nanoparticles were investigated and their viscoelastic properties were examined by creep and creep–recovery tests. The first part of this study was focused on the synthesis, structural, thermal, morphological, and surface characterizations, electrokinetic properties, and antibacterial characteristics . Furthermore, from this point of view, a new, an inexpensive raw material composed of needle‐like TiO 2 and PRh chains is believed to increase the number of scientific investigations as an attractive substitute between the antibacterial ER active fluids.…”