Next Issue
Previous Issue

E-Mail Alert

Add your e-mail address to receive forthcoming issues of this journal:

Journal Browser

Journal Browser

Table of Contents

Materials, Volume 3, Issue 3 (March 2010), Pages 1497-2195

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
View options order results:
result details:
Displaying articles 1-31
Export citation of selected articles as:
Open AccessReview Light Converting Inorganic Phosphors for White Light-Emitting Diodes
Materials 2010, 3(3), 2172-2195; https://doi.org/10.3390/ma3032172
Received: 6 January 2010 / Revised: 23 February 2010 / Accepted: 15 March 2010 / Published: 22 March 2010
Cited by 276 | PDF Full-text (1095 KB) | HTML Full-text | XML Full-text
Abstract
White light-emitting diodes (WLEDs) have matched the emission efficiency of florescent lights and will rapidly spread as light source for homes and offices in the next 5 to 10 years. WLEDs provide a light element having a semiconductor light emitting layer (blue or
[...] Read more.
White light-emitting diodes (WLEDs) have matched the emission efficiency of florescent lights and will rapidly spread as light source for homes and offices in the next 5 to 10 years. WLEDs provide a light element having a semiconductor light emitting layer (blue or near-ultraviolet (nUV) LEDs) and photoluminescence phosphors. These solid-state LED lamps, rather than organic light emitting diode (OLED) or polymer light-emitting diode (PLED), have a number of advantages over conventional incandescent bulbs and halogen lamps, such as high efficiency to convert electrical energy into light, reliability and long operating lifetime. To meet with the further requirement of high color rendering index, warm light with low color temperature, high thermal stability and higher energy efficiency for WLEDs, new phosphors that can absorb excitation energy from blue or nUV LEDs and generate visible emissions efficiently are desired. The criteria of choosing the best phosphors, for blue (450-480 nm) and nUV (380-400 nm) LEDs, strongly depends on the absorption and emission of the phosphors. Moreover, the balance of light between the emission from blue-nUV LEDs and the emissions from phosphors (such as yellow from Y3Al5O12:Ce3+) is important to obtain white light with proper color rendering index and color temperature. Here, we will review the status of phosphors for LEDs and prospect the future development. Full article
(This article belongs to the Special Issue Luminescent Materials)
Figures

Figure 1

Open AccessReview Nitrogen Doped Carbon Nanotubes from Organometallic Compounds: A Review
Materials 2010, 3(3), 2141-2171; https://doi.org/10.3390/ma3032141
Received: 11 February 2010 / Revised: 1 March 2010 / Accepted: 15 March 2010 / Published: 22 March 2010
Cited by 61 | PDF Full-text (1171 KB) | HTML Full-text | XML Full-text
Abstract
Nitrogen doped carbon nanotubes (N-CNTs) have become a topic of increased importance in the study of carbonaceous materials. This arises from the physical and chemical properties that are created when N is embedded in a CNT. These properties include modified chemical reactivity and
[...] Read more.
Nitrogen doped carbon nanotubes (N-CNTs) have become a topic of increased importance in the study of carbonaceous materials. This arises from the physical and chemical properties that are created when N is embedded in a CNT. These properties include modified chemical reactivity and modified conductivity and mechanical properties. A range of methodologies have been devised to synthesize N-CNTs. One of the procedures uses a floating catalyst in which an organometallic complex is decomposed in the gas phase in the presence of a nitrogen containing reactant to give N-CNTs. Most studies have been limited to ferrocene, ring substituted ferrocene and Fe(CO)5. This review covers the synthesis (and properties) of N-CNTs and other shaped carbon nanomaterials (SCNMs) produced using organometallic complexes. It summarizes the effects that physical parameters such as temperature, pressure, gas flow rates, type and concentration of N source etc. have on the N-CNT type, size and yields as well as the nitrogen content incorporated into the tubes that are produced from organometallic complexes. Proposed growth models for N-CNT synthesis are also reported. Full article
(This article belongs to the Special Issue Organometallic Compounds)
Figures

Figure 1

Open AccessReview Recent Progress on Enyne Metathesis: Its Application to Syntheses of Natural Products and Related Compounds
Materials 2010, 3(3), 2087-2140; https://doi.org/10.3390/ma3032087
Received: 28 December 2009 / Revised: 26 February 2010 / Accepted: 16 March 2010 / Published: 19 March 2010
Cited by 50 | PDF Full-text (996 KB) | HTML Full-text | XML Full-text
Abstract
Olefin metathesis using ruthenium carbene complexes is a useful method in synthetic organic chemistry. Enyne metathesis is also catalyzed by these complexes and various carbo- and heterocycles could be synthesized from the corresponding enynes. Dienyne metathesis, cross enyne metathesis and ring-opening enyne metathesis
[...] Read more.
Olefin metathesis using ruthenium carbene complexes is a useful method in synthetic organic chemistry. Enyne metathesis is also catalyzed by these complexes and various carbo- and heterocycles could be synthesized from the corresponding enynes. Dienyne metathesis, cross enyne metathesis and ring-opening enyne metathesis have been further developed. Various complicated compounds, such as the natural products and the related biologically active substances, could be synthesized using these metatheses reactions. Skeletal reorganization using the transition metals and metallotropic rearrangement are also discussed. Full article
(This article belongs to the Special Issue Organometallic Compounds)
Figures

Figure 1

Open AccessArticle Thermal and Optical Properties of CdS Nanoparticles in Thermotropic Liquid Crystal Monomers
Materials 2010, 3(3), 2069-2086; https://doi.org/10.3390/ma3032069
Received: 10 December 2009 / Revised: 15 February 2010 / Accepted: 17 March 2010 / Published: 19 March 2010
Cited by 25 | PDF Full-text (1097 KB) | HTML Full-text | XML Full-text
Abstract
Two new mesogenic monomers, namely 3,3’-dimethoxy-4,4’-di(hydroxyhexoxy)-N-benzylidene-o-Tolidine (Ia) and 4,4’-di(6-hydroxyhexoxy)-N-benzylidene-o-Tolidine (IIa), were reacted with cadmium sulfide (CdS) via an in situ chemical precipitation method in ethanol to produce CdS nanocomposites. A series of different mass compositions of CdS with Ia
[...] Read more.
Two new mesogenic monomers, namely 3,3’-dimethoxy-4,4’-di(hydroxyhexoxy)-N-benzylidene-o-Tolidine (Ia) and 4,4’-di(6-hydroxyhexoxy)-N-benzylidene-o-Tolidine (IIa), were reacted with cadmium sulfide (CdS) via an in situ chemical precipitation method in ethanol to produce CdS nanocomposites. A series of different mass compositions of CdS with Ia and IIa ranging from 0.1:1.0 to 1.0:1.0 (w/w) were prepared and characterized using X-ray Diffraction (XRD), Raman spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), Polarizing Optical Microscopy (POM) and Differential Scanning Calorimetry (DSC), X-ray Photoelectron Spectroscopy (XPS) and Photoluminescence Spectroscopy (PL). XRD showed that the broad peaks are ascribed to the formation of cubic CdS nanoparticles in both Ia and IIa. The average particle size for both nanocomposites was less than 5 nm with a narrower size distribution when compared with pure CdS nanoparticles. The analyses from POM and DSC demonstrated that mass composition from 0.1:1.0 up to 0.5:1.0 of CdS:Ia nanocomposites showed their enantiotropic nematic phase. On the other hand, polarizing optical microscopy (POM) for IIa nanocomposites showed that the liquid crystal property vanished completely when the mass composition was at 0.2:1.0. PL emissions for CdS: Ia or IIa nanocomposites indicated deep trap defects occurred in these both samples. The PL results revealed that addition of CdS to Ia monomers suppressed the photoluminescence intensity of Ia. However, the introduction of CdS to IIa monomers increased the photoluminescence and was at a maximum when the mass composition was 0.3:1.0, then decreased in intensity as more CdS was added. The XPS results also showed that the stoichiometric ratios of S/Cd were close to 1.0:1.0 for both types of nanocomposites for a mass composition of 1.0:1.0 (CdS:matrix). Full article
(This article belongs to the Special Issue Progress in Nanomaterials Preparation)
Figures

Figure 1

Open AccessReview Preparation and Characterization of Rare Earth Doped Fluoride Nanoparticles
Materials 2010, 3(3), 2053-2068; https://doi.org/10.3390/ma3032053
Received: 26 December 2009 / Revised: 14 January 2010 / Accepted: 18 March 2010 / Published: 19 March 2010
Cited by 33 | PDF Full-text (1344 KB) | HTML Full-text | XML Full-text
Abstract
This paper reviews the synthesis, structure and applications of metal fluoride nanoparticles, with particular focus on rare earth (RE) doped fluoride nanoparticles obtained by our research group. Nanoparticles were produced by precipitation methods using the ligand ammonium di-n-octadecyldithiophosphate (ADDP) that allows
[...] Read more.
This paper reviews the synthesis, structure and applications of metal fluoride nanoparticles, with particular focus on rare earth (RE) doped fluoride nanoparticles obtained by our research group. Nanoparticles were produced by precipitation methods using the ligand ammonium di-n-octadecyldithiophosphate (ADDP) that allows the growth of shells around a core particle while simultaneously avoiding particle aggregation. Nanoparticles were characterized on their structure, morphology, and luminescent properties. We discuss the synthesis, properties, and application of heavy metal fluorides; specifically LaF3:RE and PbF2, and group IIA fluorides. Particular attention is given to the synthesis of core/shell nanoparticles, including selectively RE-doped LaF3/LaF3, and CaF2/CaF2 core/(multi-)shell nanoparticles, and the CaF2-LaF3 system. Full article
(This article belongs to the Special Issue Luminescent Materials)
Figures

Figure 1

Open AccessArticle Synthesis and Properties of Octithiophene Dication Sterically Segregated by Annelation with Bicyclo[2.2.2]octene Units
Materials 2010, 3(3), 2037-2052; https://doi.org/10.3390/ma3032037
Received: 29 January 2010 / Revised: 13 February 2010 / Accepted: 16 March 2010 / Published: 19 March 2010
Cited by 16 | PDF Full-text (496 KB) | HTML Full-text | XML Full-text
Abstract
Octithiophene sterically segregated by annelation with bicyclo[2.2.2]octene (BCO) units was synthesized to study the unimolecular properties of longer oligothiophene dications. For the preparation of such longer oligomers, a new route for the synthesis of the monomer annelated with BCO unit at the 3,4-positions
[...] Read more.
Octithiophene sterically segregated by annelation with bicyclo[2.2.2]octene (BCO) units was synthesized to study the unimolecular properties of longer oligothiophene dications. For the preparation of such longer oligomers, a new route for the synthesis of the monomer annelated with BCO unit at the 3,4-positions of thiophene ring was developed. Attempted synthesis of octithiophene 1(8T) fully annelated with BCO units was hampered by low solubility of the product, and octithiophene 2(8T) having octyl groups instead of the BCO units at the second rings from the both ends of 1(8T) was synthesized to solve the solubility problem. Neutral 2(8T) has a lower planarity due to the steric repulsion between the octyl substituents and the neighboring thiophene units. However, dication 2(8T)2+, which was obtained as a stable salt by chemical two-electron oxidation with NO+SbF6-, has a planar quinoid structure, as judged from a linear correlation between the inverse chain length and the absorption energy for 1(nT)2+ (n = 3,4,6) and 2(8T)2+. Based on the comparison with the calculated absorption spectra and the result of ESR inactive properties, 2(8T)2+ appears to have a singlet ground state with open-shell biradical character rather than a closed-shell singlet structure. Full article
(This article belongs to the Special Issue Conjugated Oligomers)
Figures

Figure 1

Open AccessArticle A Mechanism of DC-AC Conversion in the Organic Thyristor
Materials 2010, 3(3), 2027-2036; https://doi.org/10.3390/ma3032027
Received: 5 February 2010 / Revised: 18 February 2010 / Accepted: 16 March 2010 / Published: 19 March 2010
Cited by 4 | PDF Full-text (641 KB) | HTML Full-text | XML Full-text
Abstract
The charge ordered organic salt θ-(BEDT-TTF)2CsZn(SCN)4 exhibits a giant nonlinear conduction at low temperatures. The voltage-current characteristics of this compound are similar to those of a thyristor device, after which we named it the organic thyristor. This material shows
[...] Read more.
The charge ordered organic salt θ-(BEDT-TTF)2CsZn(SCN)4 exhibits a giant nonlinear conduction at low temperatures. The voltage-current characteristics of this compound are similar to those of a thyristor device, after which we named it the organic thyristor. This material shows current oscillation in the presense of dc voltage, which arises from a mechanism different from conventional oscillating circuits, because the oscillation appears in a sample that does not show negative derivative resistance. We have performed a standard circuit analysis, and show that the voltage-current curve is “blurred” in the high current region, and the oscillation occurs in the blurred region. This type of oscillation has never been reported, and a possible origin for this is suggested. Full article
(This article belongs to the Special Issue Organic Electronic Materials)
Figures

Figure 1

Open AccessReview End-Grafted Polymer Chains onto Inorganic Nano-Objects
Materials 2010, 3(3), 1981-2026; https://doi.org/10.3390/ma3031981
Received: 20 January 2010 / Accepted: 11 March 2010 / Published: 18 March 2010
Cited by 37 | PDF Full-text (991 KB) | HTML Full-text | XML Full-text
Abstract
Organic/inorganic nanohybrid materials have attracted particular scientific and technological interest because they combine the properties of the organic and the inorganic component. Inorganic nanoparticles exhibit interesting electrical, optical, magnetic and/or catalytic properties, which are related with their nano-scale dimensions. However, their high surface-to-volume
[...] Read more.
Organic/inorganic nanohybrid materials have attracted particular scientific and technological interest because they combine the properties of the organic and the inorganic component. Inorganic nanoparticles exhibit interesting electrical, optical, magnetic and/or catalytic properties, which are related with their nano-scale dimensions. However, their high surface-to-volume ratio often induces agglomeration and leads to the loss of their attractive properties. Surface modification of the inorganic nano-objects with physically or chemically end-tethered polymer chains has been employed to overcome this problem. Covalent tethered polymer chains are realized by three different approaches: the “grafting to”, the “grafting from” and the “grafting through” method. This article reviews the synthesis of end-grafted polymer chains onto inorganic nanoparticles using “controlled/living” polymerization techniques, which allow control over the polymer characteristics and the grafting density of the end-tethered polymer chains. Full article
(This article belongs to the Special Issue Inorganic-Organic Hybrid Materials)
Figures

Graphical abstract

Open AccessReview Targeted Delivery of Protein Drugs by Nanocarriers
Materials 2010, 3(3), 1928-1980; https://doi.org/10.3390/ma3031928
Received: 28 December 2009 / Revised: 16 February 2010 / Accepted: 15 March 2010 / Published: 17 March 2010
Cited by 69 | PDF Full-text (4132 KB) | HTML Full-text | XML Full-text
Abstract
Recent advances in biotechnology demonstrate that peptides and proteins are the basis of a new generation of drugs. However, the transportation of protein drugs in the body is limited by their high molecular weight, which prevents the crossing of tissue barriers, and by
[...] Read more.
Recent advances in biotechnology demonstrate that peptides and proteins are the basis of a new generation of drugs. However, the transportation of protein drugs in the body is limited by their high molecular weight, which prevents the crossing of tissue barriers, and by their short lifetime due to immuno response and enzymatic degradation. Moreover, the ability to selectively deliver drugs to target organs, tissues or cells is a major challenge in the treatment of several human diseases, including cancer. Indeed, targeted delivery can be much more efficient than systemic application, while improving bioavailability and limiting undesirable side effects. This review describes how the use of targeted nanocarriers such as nanoparticles and liposomes can improve the pharmacokinetic properties of protein drugs, thus increasing their safety and maximizing the therapeutic effect. Full article
(This article belongs to the Special Issue Advances in Biomaterials)
Figures

Graphical abstract

Open AccessReview Freeze-Casting of Porous Biomaterials: Structure, Properties and Opportunities
Materials 2010, 3(3), 1913-1927; https://doi.org/10.3390/ma3031913
Received: 5 February 2010 / Revised: 24 February 2010 / Accepted: 16 March 2010 / Published: 17 March 2010
Cited by 115 | PDF Full-text (700 KB) | HTML Full-text | XML Full-text
Abstract
The freeze-casting of porous materials has received a great deal of attention during the past few years. This simple process, where a material suspension is simply frozen and then sublimated, provides materials with unique porous architectures, where the porosity is almost a direct
[...] Read more.
The freeze-casting of porous materials has received a great deal of attention during the past few years. This simple process, where a material suspension is simply frozen and then sublimated, provides materials with unique porous architectures, where the porosity is almost a direct replica of the frozen solvent crystals. This review focuses on the recent results on the process and the derived porous structures with regards to the biomaterials applications. Of particular interest is the architecture of the materials and the versatility of the process, which can be readily controlled and applied to biomaterials applications. A careful control of the starting formulation and processing conditions is required to control the integrity of the structure and resulting properties. Further in vitro and in vivo investigations are required to validate the potential of this new class of porous materials. Full article
(This article belongs to the Special Issue Ceramics for Healthcare)
Figures

Graphical abstract

Open AccessCommunication Charge-Transfer Controlled Crystallization of a Model Oligomer for Donor-Acceptor-Polythiophenes
Materials 2010, 3(3), 1904-1912; https://doi.org/10.3390/ma3031904
Received: 25 January 2010 / Revised: 4 March 2010 / Accepted: 16 March 2010 / Published: 17 March 2010
Cited by 6 | PDF Full-text (306 KB) | HTML Full-text | XML Full-text
Abstract
A model donor-acceptor oligomer consisting of benzodithiophene-diketone and thiophene has been investigated with regard to its molecular packing and opto-electronic properties. The crystal structure suggests that the packing is dominated by charge-transfer interactions between the electron-rich part of the molecule and the electron-poor
[...] Read more.
A model donor-acceptor oligomer consisting of benzodithiophene-diketone and thiophene has been investigated with regard to its molecular packing and opto-electronic properties. The crystal structure suggests that the packing is dominated by charge-transfer interactions between the electron-rich part of the molecule and the electron-poor part. A series of observations corroborate this assumption, among them are a charge-transfer band in the film absorption spectra and exceptionally low π-π distances. A detailed analysis of the energetic levels of the present system reveals that only the HOMO level of the acceptor is shifted by conjugation to the donor. The results can contribute to the development of improved materials for organic electronics. Full article
(This article belongs to the Special Issue Conjugated Oligomers)
Figures

Graphical abstract

Open AccessReview Polyoxometalates in Oxidative Delignification of Chemical Pulps: Effect on Lignin
Materials 2010, 3(3), 1888-1903; https://doi.org/10.3390/ma3031888
Received: 23 December 2009 / Revised: 8 March 2010 / Accepted: 12 March 2010 / Published: 16 March 2010
Cited by 16 | PDF Full-text (305 KB) | HTML Full-text | XML Full-text
Abstract
Chemical pulps are produced by chemical delignification of lignocelluloses such as wood or annual non-woody plants. After pulping (e.g., kraft pulping), the remaining lignin is removed by bleaching to produce a high quality, bright paper. The goal of bleaching is to remove lignin
[...] Read more.
Chemical pulps are produced by chemical delignification of lignocelluloses such as wood or annual non-woody plants. After pulping (e.g., kraft pulping), the remaining lignin is removed by bleaching to produce a high quality, bright paper. The goal of bleaching is to remove lignin from the pulp without a negative effect on the cellulose; for this reason, delignification should be performed in a highly selective manner. New environmentally-friendly alternatives to conventional chlorine-based bleaching technologies (e.g., oxygen, ozone, or peroxide bleaching) have been suggested or implemented. In an attempt to find inorganic agents that mimic the action of highly selective lignin-degrading enzymes and that can be applicable in industrial conditions, the researchers have focused on polyoxometalates (POMs), used either as regenerable redox reagents (in anaerobic conditions) or as catalysts (in aerobic conditions) of oxidative delignification. The aim of this paper is to review the basic concepts of POM delignification in these two processes. Full article
(This article belongs to the Special Issue Polyoxometalate Compounds)
Figures

Figure 1

Open AccessReview Collagen-Based Biomaterials for Tissue Engineering Applications
Materials 2010, 3(3), 1863-1887; https://doi.org/10.3390/ma3031863
Received: 2 February 2010 / Revised: 9 March 2010 / Accepted: 11 March 2010 / Published: 16 March 2010
Cited by 301 | PDF Full-text (284 KB) | HTML Full-text | XML Full-text
Abstract
Collagen is the most widely distributed class of proteins in the human body. The use of collagen-based biomaterials in the field of tissue engineering applications has been intensively growing over the past decades. Multiple cross-linking methods were investigated and different combinations with other
[...] Read more.
Collagen is the most widely distributed class of proteins in the human body. The use of collagen-based biomaterials in the field of tissue engineering applications has been intensively growing over the past decades. Multiple cross-linking methods were investigated and different combinations with other biopolymers were explored in order to improve tissue function. Collagen possesses a major advantage in being biodegradable, biocompatible, easily available and highly versatile. However, since collagen is a protein, it remains difficult to sterilize without alterations to its structure. This review presents a comprehensive overview of the various applications of collagen-based biomaterials developed for tissue engineering, aimed at providing a functional material for use in regenerative medicine from the laboratory bench to the patient bedside. Full article
(This article belongs to the Special Issue Advances in Biomaterials)
Figures

Figure 1

Open AccessReview Application of Nanodiamonds in Biomolecular Mass Spectrometry
Materials 2010, 3(3), 1845-1862; https://doi.org/10.3390/ma3031845
Received: 21 December 2009 / Revised: 11 February 2010 / Accepted: 12 March 2010 / Published: 15 March 2010
Cited by 7 | PDF Full-text (852 KB) | HTML Full-text | XML Full-text
Abstract
The combination of nanodiamond (ND) with biomolecular mass spectrometry (MS) makes rapid, sensitive detection of biopolymers from complex biosamples feasible. Due to its chemical inertness, optical transparency and biocompatibility, the advantage of NDs in MS study is unique. Furthermore, functionalization on the surfaces
[...] Read more.
The combination of nanodiamond (ND) with biomolecular mass spectrometry (MS) makes rapid, sensitive detection of biopolymers from complex biosamples feasible. Due to its chemical inertness, optical transparency and biocompatibility, the advantage of NDs in MS study is unique. Furthermore, functionalization on the surfaces of NDs expands their application in the fields of proteomics and genomics for specific requirements greatly. This review presents methods of MS analysis based on solid phase extraction and elution on NDs and different application examples including peptide, protein, DNA, glycan and others. Owing to the quick development of nanotechnology, surface chemistry, new MS methods and the intense interest in proteomics and genomics, a huge increase of their applications in biomolecular MS analysis in the near future can be predicted. Full article
(This article belongs to the Special Issue The New Diamond Age?)
Figures

Figure 1

Open AccessArticle Tissue Equivalents Based on Cell-Seeded Biodegradable Microfluidic Constructs
Materials 2010, 3(3), 1833-1844; https://doi.org/10.3390/ma3031833
Received: 28 January 2010 / Revised: 6 March 2010 / Accepted: 11 March 2010 / Published: 15 March 2010
Cited by 9 | PDF Full-text (1550 KB) | HTML Full-text | XML Full-text
Abstract
One of the principal challenges in the field of tissue engineering and regenerative medicine is the formation of functional microvascular networks capable of sustaining tissue constructs. Complex tissues and vital organs require a means to support oxygen and nutrient transport during the development
[...] Read more.
One of the principal challenges in the field of tissue engineering and regenerative medicine is the formation of functional microvascular networks capable of sustaining tissue constructs. Complex tissues and vital organs require a means to support oxygen and nutrient transport during the development of constructs both prior to and after host integration, and current approaches have not demonstrated robust solutions to this challenge. Here, we present a technology platform encompassing the design, construction, cell seeding and functional evaluation of tissue equivalents for wound healing and other clinical applications. These tissue equivalents are comprised of biodegradable microfluidic scaffolds lined with microvascular cells and designed to replicate microenvironmental cues necessary to generate and sustain cell populations to replace dermal and/or epidermal tissues lost due to trauma or disease. Initial results demonstrate that these biodegradable microfluidic devices promote cell adherence and support basic cell functions. These systems represent a promising pathway towards highly integrated three-dimensional engineered tissue constructs for a wide range of clinical applications. Full article
(This article belongs to the Special Issue Advances in Biomaterials)
Figures

Graphical abstract

Back to Top