Nanomaterials

1032 KiB

Open AccessReview

Polyhedral Oligomeric Silsesquioxane (POSS)-Containing Polymer Nanocomposites

by Ebunoluwa Ayandele, Biswajit Sarkar and Paschalis Alexandridis

Nanomaterials 2012, 2(4), 445-475; https://doi.org/10.3390/nano2040445 - 6 Dec 2012

Cited by 342 | Viewed by 25909

Hybrid materials with superior structural and functional properties can be obtained by incorporating nanofillers into polymer matrices. Polyhedral oligomeric silsesquioxane (POSS) nanoparticles have attracted much attention recently due to their nanometer size, the ease of which these particles can be incorporated into polymeric [...] Read more.

Hybrid materials with superior structural and functional properties can be obtained by incorporating nanofillers into polymer matrices. Polyhedral oligomeric silsesquioxane (POSS) nanoparticles have attracted much attention recently due to their nanometer size, the ease of which these particles can be incorporated into polymeric materials and the unique capability to reinforce polymers. We review here the state of POSS-containing polymer nanocomposites. We discuss the influence of the incorporation of POSS into polymer matrices via chemical cross-linking or physical blending on the structure of nanocomposites, as affected by surface functional groups, and the POSS concentration. Full article

(This article belongs to the Special Issue Composite Nanomaterials)

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733 KiB

Open AccessArticle

Spontaneous Deposition of Prussian Blue on Multi-Walled Carbon Nanotubes and the Application in an Amperometric Biosensor

by Yanli Yao, Xiaoyun Bai and Kwok-Keung Shiu

Nanomaterials 2012, 2(4), 428-444; https://doi.org/10.3390/nano2040428 - 27 Nov 2012

Cited by 27 | Viewed by 10186

Abstract

A simple method has been developed for the spontaneous deposition of Prussian blue (PB) particles from a solution containing only ferricyanide ions onto conducting substrates such as indium tin oxide glass, glassy carbon disk and carbon nanotube (CNT) materials. Formation of PB deposits [...] Read more.

A simple method has been developed for the spontaneous deposition of Prussian blue (PB) particles from a solution containing only ferricyanide ions onto conducting substrates such as indium tin oxide glass, glassy carbon disk and carbon nanotube (CNT) materials. Formation of PB deposits was confirmed by ultraviolet-visible absorption spectrometry and electrochemical techniques. The surface morphology of the PB particles deposited on the substrates was examined by atomic force microscopy and scanning electron microscopy. CNT/PB composite modified glassy carbon electrodes exhibited an electrocatalytic property for hydrogen peroxide reduction. These modified electrodes exhibited a high sensitivity for electrocatalytic reduction of hydrogen peroxide at −0.05 V (vs. Ag|AgCl), probably due to the synergistic effect of CNT with PB. Then, CNT/PB modified electrodes were further developed as amperometric glucose biosensors. These biosensors offered a linear response to glucose concentration from 0.1 to 0.9 mM with good selectivity, high sensitivity of 0.102 A M⁻¹ cm⁻² and short response time (within 2 s) at a negative operation potential of −0.05 V (vs. Ag|AgCl). The detection limit was estimated to be 0.01 mM at a signal-to-noise ratio of 3. Full article

(This article belongs to the Special Issue CNT based Nanomaterials)

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624 KiB

Open AccessArticle

Maghemite Intercalated Montmorillonite as New Nanofillers for Photopolymers

by Bassam Tarablsi, Christelle Delaite, Jocelyne Brendle and Celine Croutxe-Barghorn

Nanomaterials 2012, 2(4), 413-427; https://doi.org/10.3390/nano2040413 - 19 Nov 2012

Cited by 7 | Viewed by 8994

Abstract

In this work, maghemite intercalated montmorillonite (γFe₂O₃-MMT)/polymer nanocomposites loaded with 1 or 2 wt.% of nanofillers were obtained by photopolymerization of difunctional acrylate monomers. The γFe₂O₃-MMT nanofillers were prepared by a new method based on [...] Read more.

In this work, maghemite intercalated montmorillonite (γFe₂O₃-MMT)/polymer nanocomposites loaded with 1 or 2 wt.% of nanofillers were obtained by photopolymerization of difunctional acrylate monomers. The γFe₂O₃-MMT nanofillers were prepared by a new method based on the in situ formation of maghemite in the interlayer space of Fe-MMT using a three step process. X-ray diffraction (XRD), chemical analysis, TG/DTA and transmission electron microscopy (TEM) characterization of these nanofillers indicated the efficiency of the synthesis. When following the kinetics of the photopolymerization of diacrylate-γFe₂O₃-MMT nanocomposites using FTIR spectroscopy no significant inhibition effect of the nanofillers was observed at a loading up to 2 wt.%. These innovative nanocomposites exhibit improved mechanical properties compared to the crude polymer. Full article

(This article belongs to the Special Issue Composite Nanomaterials)

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7714 KiB

Open AccessReview

Recent Advances in Nanostructured Thermoelectric Half-Heusler Compounds

by Wenjie Xie, Anke Weidenkaff, Xinfeng Tang, Qingjie Zhang, Joseph Poon and Terry M. Tritt

Nanomaterials 2012, 2(4), 379-412; https://doi.org/10.3390/nano2040379 - 14 Nov 2012

Cited by 296 | Viewed by 18254

Abstract

Half-Heusler (HH) alloys have attracted considerable interest as promising thermoelectric (TE) materials in the temperature range around 700 K and above, which is close to the temperature range of most industrial waste heat sources. The past few years have seen nanostructuing play an [...] Read more.

Half-Heusler (HH) alloys have attracted considerable interest as promising thermoelectric (TE) materials in the temperature range around 700 K and above, which is close to the temperature range of most industrial waste heat sources. The past few years have seen nanostructuing play an important role in significantly enhancing the TE performance of several HH alloys. In this article, we briefly review the recent progress and advances in these HH nanocomposites. We begin by presenting the structure of HH alloys and the different strategies that have been utilized for improving the TE properties of HH alloys. Next, we review the details of HH nanocomposites as obtained by different techniques. Finally, the review closes by highlighting several promising strategies for further research directions in these very promising TE materials. Full article

(This article belongs to the Special Issue Composite Nanomaterials)

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894 KiB

Open AccessArticle

Evaluation of the Mechanism of the Gold Cluster Growth during Heating of the Composite Gold-Polytetrafluoroethylene Thin Film

by Konstantin Grytsenko, Valeri Lozovski, Galyna Strilchuk and Sigurd Schrader

Nanomaterials 2012, 2(4), 366-378; https://doi.org/10.3390/nano2040366 - 7 Nov 2012

Cited by 4 | Viewed by 7218

Abstract

Nanocomposite films consisting of gold inclusions in the polytetrafluoroethylene (PTFE) matrix were obtained by thermal vacuum deposition. Annealing of the obtained films with different temperatures was used to measure varying of film morphologies. The dependence of optical properties of the films on their [...] Read more.

Nanocomposite films consisting of gold inclusions in the polytetrafluoroethylene (PTFE) matrix were obtained by thermal vacuum deposition. Annealing of the obtained films with different temperatures was used to measure varying of film morphologies. The dependence of optical properties of the films on their morphology was studied. It was established that absorption and profile of the nanocomposite film obtained by thermal vacuum deposition can be changed with annealing owing to the fact that different annealing temperatures lead to different average particle sizes. A method to calculate the optical properties of nanocomposite thin films with inclusions of different sizes was proposed. Thus, comparison of experimental optical spectra with the spectra obtained during the simulation enables estimating average sizes of inclusions. The calculations give the possibility of understanding morphological changes in the structures. Full article

(This article belongs to the Special Issue Composite Nanomaterials)

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3508 KiB

Open AccessArticle

Characterization of Hybrid Epoxy Nanocomposites

by Shelly Simcha, Ana Dotan, Samuel Kenig and Hanna Dodiuk

Nanomaterials 2012, 2(4), 348-365; https://doi.org/10.3390/nano2040348 - 26 Oct 2012

Cited by 18 | Viewed by 7538

Abstract

This study focused on the effect of Multi Wall Carbon Nanotubes (MWCNT) content and its surface treatment on thermo-mechanical properties of epoxy nanocomposites. MWCNTs were surface treated and incorporated into two epoxy systems. MWCNT's surface treatments were based on: (a) Titania coating obtained [...] Read more.

This study focused on the effect of Multi Wall Carbon Nanotubes (MWCNT) content and its surface treatment on thermo-mechanical properties of epoxy nanocomposites. MWCNTs were surface treated and incorporated into two epoxy systems. MWCNT's surface treatments were based on: (a) Titania coating obtained by sol-gel process and (b) a nonionic surfactant. Thermo-mechanical properties improvement was obtained following incorporation of treated MWCNT. It was noticed that small amounts of titania coated MWCNT (0.05 wt %) led to an increase in the glass transition temperature and stiffness. The best performance was achieved adding 0.3 wt % titania coated MWCNT where an increase of 10 °C in the glass transition temperature and 30% in storage modulus were obtained. Full article

(This article belongs to the Special Issue Composite Nanomaterials)

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1822 KiB

Open AccessArticle

Improved Dispersion of Carbon Nanotubes in Polymers at High Concentrations

by Chao-Xuan Liu and Jin-Woo Choi

Nanomaterials 2012, 2(4), 329-347; https://doi.org/10.3390/nano2040329 - 26 Oct 2012

Cited by 177 | Viewed by 17798

Abstract

The polymer nanocomposite used in this work comprises elastomer poly(dimethylsiloxane) (PDMS) as a polymer matrix and multi-walled carbon nanotubes (MWCNTs) as a conductive nanofiller. To achieve uniform distribution of carbon nanotubes within the polymer, an optimized dispersion process was developed, featuring a strong [...] Read more.

The polymer nanocomposite used in this work comprises elastomer poly(dimethylsiloxane) (PDMS) as a polymer matrix and multi-walled carbon nanotubes (MWCNTs) as a conductive nanofiller. To achieve uniform distribution of carbon nanotubes within the polymer, an optimized dispersion process was developed, featuring a strong organic solvent—chloroform, which dissolved PDMS base polymer easily and allowed high quality dispersion of MWCNTs. At concentrations as high as 9 wt.%, MWCNTs were dispersed uniformly through the polymer matrix, which presented a major improvement over prior techniques. The dispersion procedure was optimized via extended experimentation, which is discussed in detail. Full article

(This article belongs to the Special Issue Composite Nanomaterials)

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1903 KiB

Open AccessArticle

Simultaneous Patterning of Independent Metal/Metal Oxide Multi-Layer Films Using Two-Tone Photo-Acid Generating Compound Systems

by Christopher E. J. Cordonier and Hideo Honma

Nanomaterials 2012, 2(4), 312-328; https://doi.org/10.3390/nano2040312 - 16 Oct 2012

Cited by 4 | Viewed by 6603

Abstract

(1) The photo-induced solubility and positive-tone direct photo-patterning of iron, copper and lanthanides chelated with 4-(2-nitrobenzyloxycarbonyl)catechol (NBOC) or 4-(6-nitroveratryloxycarbonyl)catechol (NVOC) was investigated. Photo-patterning of iron, copper, cerium, samarium, europium, terbium, dysprosium, holmium, erbium and lutetium complexes was accomplished. Continuous films were formed by [...] Read more.

(1) The photo-induced solubility and positive-tone direct photo-patterning of iron, copper and lanthanides chelated with 4-(2-nitrobenzyloxycarbonyl)catechol (NBOC) or 4-(6-nitroveratryloxycarbonyl)catechol (NVOC) was investigated. Photo-patterning of iron, copper, cerium, samarium, europium, terbium, dysprosium, holmium, erbium and lutetium complexes was accomplished. Continuous films were formed by the pyrolysis of metal complex films at 500 °C. (2) Based on the difference in the photo-reaction excitation wavelength profile of NBOC and NVOC complexes, a short and simple method for simultaneous micro-patterning of two independent films on each side of a transparent glass substrate was developed. Using the developed procedure, indium tin oxide and/or titanium oxide films were formed on each side of a quartz substrate without use of resist or etching. Full article

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Nanomaterials, Volume 2, Issue 4 (December 2012) – 8 articles , Pages 312-475

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