Search

In this work, we demonstrate an inimitable liquid crystalline template strategy for the preparation of water dispersible electrically conducting poly(3,4-ethylenedioxythiophene) nanospindles (PEDOTSs). PEDOTSs were formed during the polymerization of the spindle shaped liquid crystalline phase of “EDOT–PDPSA” which was formed by the specific interactions of 3,4-ethylenedioxythiophene (EDOT) with 3-pentadecyl phenol-4-sulphonic acid (PDPSA). Liquid crystalline phases were characterized by Polarized Light Microscopic (PLM) analyses, rheology and XRD. Morphology and solid state ordering of conducting nanospindles were characterized by SEM, TEM and XRD. PEDOTSs exhibited an electrical conductivity of � 2.79 S cm � 1 and a good thermal stability (� 300 � C), which suggests their applicability in fabricating high temperature electronic devices. Furthermore, electrochemical studies of PEDOTS modified glassy carbon electrodes (GCEs) showed an oxidation peak of ascorbic acid at a lower potential of 0.046 V with a peak current about 10 times (91.68 mA) higher than that of the bare GCE with excellent electrode stability, proposing that it can be used as a steady electrode for the electro-catalytic oxidation of similar molecules.

In present paper we demonstrate that aqueous microgels can be used as containers for in-situ synthesis of hydroxyapatite. The hydroxyapatite nanocrystals (HAp NCs) become integrated into microgels forming hybrid colloids. The HAp NCs loading in the microgel can be varied in a broad range. The HAp NCs are homogeneously distributed within the microgel corona. The deposition of the inorganic nanocrystals decreases colloidal stability of the microgels and leads to particle aggregation at high HAp NCs loading. Due to the strong interactions between HAp NCs and polymer chains the swelling degree of microgel decreases and temperature-sensitive properties disappear at high loading of the inorganic component. The hybrid colloids can be used as building blocks for the preparation of nano-structured films on solid substrates.

The surface immobilization of oligo- and poly(ethylene glycol) on solids is a widely used approach to prevent the nonspecific adsorption of proteins, bacteria, and cells. A novel tri(ethylene glycol) derivative, phosphoric acid-mono(22-carboxy-12,15,18,21-tetraoxadocosyl) ester, was synthesized with the aim to produce self-assembled monolayers (SAMs) on metal/metal oxide surfaces. This compound contains two reactive, terminal moieties: the phosphoric acid group as anchor to the surface, and the carboxylic group as linker for further attachment of molecules such as peptides and proteins to be present at the surface. The adsorption on titanium-dioxide-coated substrates was studied quantitatively and the resulting SAMs were characterized by angle-dependent X-ray photoelectron spectroscopy (XPS) and spectroscopic ellipsometry. XPS data showed that the monomolecular layer is attached with the phosphate group to the substrate, but not fully ordered. The dry adlayer thickness was determined to be 13.4 A, which is less than expected for a densely packed monolayer. Surface concentration calculated from ellipsometry data resulted in a grafting density of 2.03 molecules/nm2.

In the present paper, we report the preparation of hybrid temperature-sensitive microgels which include magnetite nanoparticles in their structure. Polymeric microgels have been prepared by surfactant-free emulsion copolymerization of acetoacetoxyethyl methacrylate (AAEM) and N-vinylcaprolactam (VCL) in water with a water-soluble azo-initiator. The obtained microgels possess a low critical solution temperature (LCST) in water solutions, with a rapid decrease of the particle size being observed at elevated temperatures. Magnetite was deposited directly into microgels, leading to the formation of composite particles which combine both temperature-sensitive and magnetic properties. The influence of magnetite load on microgel size, morphology, swelling-deswelling behavior, and stability is discussed.

Many technical applications require substances providing special abilities in connecting different materials to each other. Beginning from applications for corrosion inhibition to improved adhesion abilities of laquers on selected metals like aluminium, titanium or tantalum, some special adhesion promoters on base of phosponic acid and trichlorsilane were developed. At last electronic devices basing on conducting polymers need adhesion promoters to bound the conducting polymers to supporting materials consisting of technical polymers or silicon wafers and other inorganic surfaces. This requires new adhesion promoters with polymerizable groups like thiophen or pyrrol.

Stable core-shell polypyrrole (PPy) dispersions were prepared by using polystyrene (PST) or poly (styrene-co-butyl acrylate) (PST-co-BuA) as the core. and polypyrrole as the shell. SEM images showed that PPy/PST composites with a thin homogeneous overlayer of polypyrrole can he prepared when uncharged polymeric stabilizer is grafted onto the particle surface. Composite particles with raspberry morphology were obtained when the core particles were stabilized by surfactant with charge. The stability, morphology and conductivity of PPy composites have been investigated.

Water dispersible nanostructured multifunctional polyaniline-laponite-keggin iron cation composites (PPIL) were prepared by the oxidative polymerization of aniline in the presence of an aqueous dispersion of keggin iron-laponite (PIL) at room temperature. Negatively charged ions on the surface and residual positive charges on the edges of the laponite disc adsorb both keggin iron and aniline through ion-dipole and ionic interactions and can act as a micellar template during polymerisation. We suggest that keggin cages act as linkages between disorganized laponite sheets and during polymerisation, the disorganised PIL discs are co-structured and self-assembled with the formed PANI and engulfed layers and rolled sheets of nanotubes. These multifunctional composites exhibited electrical conductivity ∼ 5.7 × 10−1 S cm−1, saturation magnetization ∼ 9.0 × 10−1 emu g−1 with coercivity 8.2 Oe and thermal stability ∼ 300 °C, revealing their utility as a novel precursor for many high technological applications.

In present paper we report on a preparation of hybrid microgels filled with gold nano-particles (AuNPs). Temperature-sensitive VCL/AAEM microgels have been used as containers for deposition of Au by in situ formation of gold nano-particles. Synthesis of AuNPs has been performed by two methods: a) reduction of chloroauric acid with sodium borhydride and b) reduction of chloroauric acid by sodium citrate under ultrasonic agitation. In both cases AuNPs were deposited directly into microgels leading to formation of composite particles which exhibit temperature-sensitive properties, tunable gold contents and high colloidal stability. The influence of Au load on microgel size, morphology, swellingdeswelling behaviour and stability is discussed.