Residual Hydroxyl Research Articles

Mechanism of lipid droplet formation by the yeast Sei1/Ldb16 Seipin complex

Lipid droplets (LDs) are universal lipid storage organelles with a core of neutral lipids, such as triacylglycerols, surrounded by a phospholipid monolayer. This unique architecture is generated during LD biogenesis at endoplasmic reticulum (ER) sites marked by Seipin, a conserved membrane protein mutated in lipodystrophy. Here structural, biochemical and molecular dynamics simulation approaches reveal the mechanism of LD formation by the yeast Seipin Sei1 and its membrane partner Ldb16. We show that Sei1 luminal domain assembles a homooligomeric ring, which, in contrast to other Seipins, is unable to concentrate triacylglycerol. Instead, Sei1 positions Ldb16, which concentrates triacylglycerol within the Sei1 ring through critical hydroxyl residues. Triacylglycerol recruitment to the complex is further promoted by Sei1 transmembrane segments, which also control Ldb16 stability. Thus, we propose that LD assembly by the Sei1/Ldb16 complex, and likely other Seipins, requires sequential triacylglycerol-concentrating steps via distinct elements in the ER membrane and lumen.

Spectroscopic and luminescent properties of Nd3+-Al3+ co-doped silica glass prepared by spark plasma sintering

The Nd3+-Al3+ co-doped silica glass has drawn much attention due to the stability and efficient lasing emissions, while the high preparation temperature and residual hydroxyl groups restrict the further improvement of optical performance. In this work, transparent Nd3+-Al3+ co-doped glasses have been synthesized by spark plasma sintering at 980°C within 10 mins. Besides, adopting mesoporous powders as raw materials is beneficial to the homogeneous dispersion of ions in the glass. The transmittance, structure and luminescent properties were systematically investigated. The Judd-Ofelt intensity parameters were obtained to analyze the Al3+ co-doping effects. The PL intensity strongly depends on the ions concentration and the best value is obtained when the Nd3+ concentration is 1.0 mol% and ratio of Nd:Al is 1:7. In addition, the calculated emission cross section is 2.12, which is larger than the majority of previously reported values, suggesting that as-prepared silica glasses are candidates for laser host materials.

Handedness Inversion in Chiral Nematic (Ethyl)cellulose Solutions: Effects of Substituents and Temperature

Various acylates and phenylcarbamates of (ethyl)cellulose (EC) were synthesized by acylation and carbanilation, respectively, of the residual hydroxyls of an EC (ethyl DS = 2.50). The acyl substituents adopted were propionyl, butyryl, cyclohexanoyl, and adamantoyl groups, and the phenylcarbamoyl substituents included 3-chlorophenylcarbamoyl, 4-chlorophenylcarbamoyl, 3-methylphenylcarbamoyl, and bare phenylcarbamoyl groups. Chiral nematic mesophases of the EC derivatives, formed in chloroform, acetic acid (AA), and dichloroacetic acid (DCA), were examined by various optical techniques for evaluation of the helical pitch (P) in a set of absolute value and twist sense. The lyotropic samples prepared with DCA (20 °C) always assumed a right-handed chiral nematic structure, regardless of the degree of acyl (or phenylcarbamoyl) substitution (DSAcyl (or DSPC), ≤0.50). The chiral nematic series with AA (20 °C) and chloroform (5 °C) showed an inversion of the twist sense from being left-handed to right-handed, when DSAcyl (or DSPC) of each derivative was increased. The critical DS value for the inversion varied depending on the chain length, bulkiness, and polar nature of the employed substituent. For all of the lyotropic series explored, it was generalized that a temperature elevation strengthens a left-handed twisting power in each chiral nematic mesophase. Reversal of the twist handedness was also observed in a cycle of heating and cooling of some chiral nematics in AA. This was interpreted as being due to compensation in the strength of the two chiral interactions, i.e., steric repulsion and dispersion interaction between mesogenic molecules, contributing in mutually opposite signs to the twisting power (2πP–1) of the mesophase.

A facile and versatile superhydrophilic coating on biodegradable PLA stent with stepwise assembly of metal/phenolic networks for mimicking endothelium function

The achievement of the desired hemocompatibility, anti-inflammatory, and rapid endothelialization properties has significantly contributed to the success of implantable blood-contacting materials, especially vascular stents. In this study, we constructed a facile and versatile superhydrophilic coating via the stepwise deposition of metal/phenolic networks (MPNs) using a layer-by-layer assembly technique. Tannic acid and copper ions were employed for the fabrication of MPNs, and the surface roughness and the number of hydrophilic phenolic groups were gradually increased, ultimately leading to the generation of a superhydrophilic coating, where the copper ions were also effectively incorporated. Owing to the superhydrophilicity of the coating, the binding of serum adhesion proteins, such as albumin and fibrinogen, to the surface was strongly inhibited, thereby conferring a potent antithrombotic ability. In addition, a potent antioxidant and anti-inflammatory effects were achieved through the deposition of a large amount of residual phenolic hydroxyl groups on the surface. The incorporated copper ions could also mimic endothelial function through the continuously catalyzed decomposition of endogenous S-nitrothiols (RSNOs) to release nitric oxide (NO) in situ in a controlled manner. The synergistic contribution effect of NO and superhydrophilicity, further inhibited the adhesion/activation of platelets. The optimized coating significantly inhibited the adhesion and activation of platelets, selectively supported the adhesion of endothelial cells, and suppressed the proliferation of smooth muscle cells. Such superhydrophilic coating with the incorporation of copper ions adequately addressed the basic requirements of vascular stents, in terms of antithrombosis, anti-restenosis, and enhanced endothelialization in vivo, demonstrating a promising approach for the clinical application of vascular implants.

Morphology-controllable amphiphilic cellulose microgels made from self-assembly of hydrophobic long-chain bromide-alkylated-cellulose/gelatin copolymer

A cellulose-based microgel is firstly synthesized via chemically coupling gelatin and cellulose, and then amphiphilic cellulose copolymers (HMGC) are prepared by alkylated cellulose-based microgel from different long-chain alkyl groups. The long-chain alkyl group is mainly bonded onto the residual hydroxyl group at C6 from the AGU of cellulose and the imino groups of gelatin, respectively. The results of self-assembly behavior of HMGC demonstrate that the critical aggregation concentrations of the microgels are in the range from 0.628 to 0.075 mg/mL, and the corresponding hydrodynamic diameters are between 104–1000 nm. Besides, the HMGC can self-assemble into microgels of various morphologies including cotton flocculence, sphere, rod-like, vesicle, flower-like cluster, snowflake-like, urchin-like, and coral shapes. These novel morphologies can be controlled by adjusting the degree of alkylation, the length of the alkyl chain, and the concentration of microgel. Furthermore, the possible formation mechanism of the multiform microgels is proposed from the chain conformation.

Enzyme inspired polymer functionalized with an artificial catalytic triad

At the heart of an enzyme's structure is the active catalytic site, which, together with the surrounding amino-acid residues, tunes the substrate properties in the electrostatic microenvironment. Taking inspiration from nature's catalytic triad, consisting of a hydroxyl group of a serine residue, an imidazole group of a histidine residue, and a carboxyl group of an aspartic acid, a polymer scaffolded enzyme mimic is incorporated with artificial catalytic triad units. It is demonstrated that controlling the local environment of the artificial triad affects catalytic activity. Compared to a water soluble artificial catalytic triad, enhanced esterolytic activity of p-nitrophenyl benzoate was observed for the polymeric catalyst possibly due to the hydrophobic microenvironment formed by the tertiary structure of the polymer backbone. The different environments were supported by molecular dynamics simulations. It is further demonstrated that the cross-linked catalytic triad functional polystyrene could be used as a reusable solid support catalyst for esterolysis.

Bias Stress Stability of Solution-Processed Nano Indium Oxide Thin Film Transistor.

In this paper, the effects of annealing temperature and other process parameters on spin-coated indium oxide thin film transistors (In2O3-TFTs) were studied. The research shows that plasma pretreatment of glass substrate can improve the hydrophilicity of glass substrate and stability of the spin-coating process. With Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) analysis, it is found that In2O3 thin films prepared by the spin coating method are amorphous, and have little organic residue when the annealing temperature ranges from 200 to 300 °C. After optimizing process conditions with the spin-coated rotating speed of 4000 rpm and the annealing temperature of 275 °C, the performance of In2O3-TFTs is best (average mobility of 1.288 cm2·V−1·s−1, Ion/Ioff of 5.93 × 106, and SS of 0.84 V·dec−1). Finally, the stability of In2O3-TFTs prepared at different annealing temperatures was analyzed by energy band theory, and we identified that the elimination of residual hydroxyl groups was the key influencing factor. Our results provide a useful reference for high-performance metal oxide semiconductor TFTs prepared by the solution method.

Highly Hydrophobic, Homogeneous Suspension and Resin by Graft Copolymerization Modification of Cellulose Nanocrystal (CNC)

Cellulose nanocrystal (CNC) is a nanoscale colloid with superior potential for coatings, liquid crystal displays, and optoelectronics. However, to date, the presence of hydrophilicity still limits its application. Multifunction via graft copolymerization modification of CNC appears to be breaking into a new direction. In this study, we used the residual hydroxyl groups on the CNC to react with 2-bromoisobu-tyryl bromide, and the initiator was therefore anchored on the CNC surface. Through atom transfer radical polymerization (ATRP), CNC was successfully grafted to azobenzene monomer, i.e., 9-[4-[2-[4-(trifluorometh) phenyl] diazenyl] phenoxy] nonayl acrylate (FAZO). After a series of characterization methods, such as FTIR, NMR and XRD, it was found that the surface water contact angle of the CNC-PFAZO prepared by the modification was as high as 134.4°, and the high hydrophilicity of this material could be maintained for up to one month, even longer.

Novel green and cost-effective preparation of acetylated lignin at high temperature without further separation

In order to realize the green and low-cost industrial production of acetylated lignin, this work proposes the heterogeneous reaction to acetylated lignin (ACAL) without catalysts and solvents at high temperature. The influence of reaction temperature and reaction time were investigated by IR, UV–vis, thermogravimetric analysis and water contact angle. Results showed that the optimum technological conditions were about 150 °C and 6 h. The degree of acetylation and the amount of residual phenolic hydroxyl groups of ACAL was 2.49 and 34.2%, respectively. Compared with conventional acetylated lignin, the ACAL had similar hydrophobicity with a water contact angle of 62.0°. The DTG peak of ACAL at about 200 °C reduced to 0.07 than the traditional acetylated lignin. The tensile strength and elongation of poly-lactic acid with 5 wt% ACAL increased to 64.03 MPa and 10.80%, respectively. ACAL revealed a great potential for mass production and applications owing to the eco-friendly and cost-effective modified method.

Chasing the Major Sphingolipids on Earth: Automated Annotation of Plant Glycosyl Inositol Phospho Ceramides by Glycolipidomics.

Glycosyl inositol phospho ceramides (GIPCs) are the major sphingolipids on earth, as they account for a considerable fraction of the total lipids in plants and fungi, which in turn represent a large portion of the biomass on earth. Despite their obvious importance, GIPC analysis remains challenging due to the lack of commercial standards and automated annotation software. In this work, we introduce a novel GIPC glycolipidomics workflow based on reversed-phase ultra-high pressure liquid chromatography coupled to high-resolution mass spectrometry. For the first time, automated GIPC assignment was performed using the open-source software Lipid Data Analyzer (LDA), based on platform-independent decision rules. Four different plant samples (salad, spinach, raspberry, and strawberry) were analyzed and the results revealed 64 GIPCs based on accurate mass, characteristic MS2 fragments and matching retention times. Relative quantification using lactosyl ceramide for internal standardization revealed GIPC t18:1/h24:0 as the most abundant species in all plants. Depending on the plant sample, GIPCs contained mainly amine, N-acetylamine or hydroxyl residues. Most GIPCs revealed a Hex-HexA-IPC core and contained a ceramide part with a trihydroxylated t18:0 or a t18:1 long chain base and hydroxylated fatty acid chains ranging from 16 to 26 carbon atoms in length (h16:0–h26:0). Interestingly, four GIPCs containing t18:2 were observed in the raspberry sample, which was not reported so far. The presented workflow supports the characterization of different plant samples by automatic GIPC assignment, potentially leading to the identification of new GIPCs. For the first time, automated high-throughput profiling of these complex glycolipids is possible by liquid chromatography-high-resolution tandem mass spectrometry and subsequent automated glycolipid annotation based on decision rules.

Crystal structure of GH30-7 endoxylanase C from the filamentous fungus Talaromyces cellulolyticus.

GH30-7 endoxylanase C from the cellulolytic fungus Talaromyces cellulolyticus (TcXyn30C) belongs to glycoside hydrolase family 30 subfamily 7, and specifically releases 22-(4-O-methyl-α-D-glucuronosyl)-xylobiose from glucuronoxylan, as well as various arabino-xylooligosaccharides from arabinoxylan. TcXyn30C has a modular structure consisting of a catalytic domain and a C-terminal cellulose-binding module 1 (CBM1). In this study, the crystal structure of a TcXyn30C mutant which lacks the CBM1 domain was determined at 1.65 Å resolution. The structure of the active site of TcXyn30C was compared with that of the bifunctional GH30-7 xylanase B from T. cellulolyticus (TcXyn30B), which exhibits glucuronoxylanase and xylobiohydrolase activities. The results revealed that TcXyn30C has a conserved structural feature for recognizing the 4-O-methyl-α-D-glucuronic acid (MeGlcA) substituent in subsite -2b. Additionally, the results demonstrated that Phe47 contributes significantly to catalysis by TcXyn30C. Phe47 is located in subsite -2b and also near the C-3 hydroxyl group of a xylose residue in subsite -2a. Substitution of Phe47 with an arginine residue caused a remarkable decrease in the catalytic efficiency towards arabinoxylan, suggesting the importance of Phe47 in arabinoxylan hydrolysis. These findings indicate that subsite -2b of TcXyn30C has unique structural features that interact with arabinofuranose and MeGlcA substituents.

Effect of amino acids present at the carboxyl end of succinimidyl residue on the rate constants for succinimidyl hydrolysis in small peptides

Structural alterations of aspartyl and asparaginyl residues in various proteins can lead to their malfunction, which may result in severe health disorders. The formation and hydrolysis of succinimidyl intermediates are crucial in specific protein modifications. Nonetheless, only few studies investigating the hydrolysis of succinimidyl intermediates have been published. In this study, we established a method to prepare peptides bearing succinimidyl residues using recombinant protein l-isoaspartyl methyltransferase and ultrafiltration units. Using succinimidyl peptides, we examined the effect of amino acid residues on succinimidyl hydrolysis at the carboxyl end of succinimidyl residues and determined the rate constant of hydrolysis for each peptide. The rate constant of succinimidyl hydrolysis in the peptide bearing a Ser residue at the carboxyl side (0.50 ± 0.02 /h) was 3.0 times higher than that for the peptide bearing an Ala residue (0.17 ± 0.01 /h), whereas it was just 1.2 times higher for the peptide bearing a Gly residue (0.20 ± 0.01 /h). The rate constant of succinimidyl formation in the peptide bearing a Ser residue [(2.44 ± 0.11) × 10−3 /d] was only 1.2 times higher than that for the peptide bearing an Ala residue ([1.87 ± 0.09) × 10−3 /d], whereas 5.5 times higher for the peptide bearing a Gly residue [(10.2 ± 0.2) × 10−3 /d]. These results show that the Gly and Ser residues at the carboxyl end of the succinimidyl residue have opposing roles in succinimidyl formation and hydrolysis. Catalysis of Ser residue's hydroxyl group plays a crucial role in succinimidyl hydrolysis.

Investigations into the thermal stability of sol‐gel‐derived glasses as models for thermally grown oxides

AbstractThe thermal stability of sol‐gel‐derived silica and borosilicate glasses exposed to dry O2 at 800 and 1200°C for 100 hours was characterized by weight change, thermal transitions, morphology, structure, and composition to investigate suitability as models for thermally grown oxides. Rapid weight loss was observed in the first few hours of isothermal exposure for borosilicate glasses, followed by constant weight loss at a low rate for the balance of the exposure. Weight loss resulted from loss of residual hydroxyl species retained from the sol‐gel synthesis, and from oxidation of carbon retained from thermal decomposition of the organic precursors by pyrolysis. Characterization of the sol‐gel‐derived glasses showed structural similarities to silica and binary borosilicate glasses synthesized by melt or vapor deposition methods, and to thermally grown oxides. Oxygen transport mechanisms through the sol‐gel‐derived glasses is not thought to be affected by the retained carbon. However, a silica‐enriched glass surface resulting from boria volatility, observed from a borosilicate glass exposed dry O2 at 1200°C, will slow O2 transport rates. The results show that sol‐gel‐derived silica and borosilicate glasses can be used as models for thermally grown oxides.

Preparation and Application of Partially Substituted Phenylcarbamate-(3-(2-O-β-cyclodextrin)-2-hydroxypropoxy)-propylsilyl-Appended Silica Particles as Chiral Stationary Phase for Multi-mode HPLC

A new type of partially substituted cyclodextrin-bonded silica particles, phenylcarbamate-(3-(2-O-β-cyclodextrin)-2-hydroxypropoxy)-propylsilyl-appended silica (P-CD-HPS), has been successfully prepared and used as chiral stationary phase (CSP) in high-performance liquid chromatography (HPLC) under normal-phase, reversed-phase, and polar organic mobile-phase conditions. The P-CD-HPS was characterized by elemental analysis and Fourier transform infrared spectroscopic (FTIR) analysis. The chromatographic performance of the new-phase P-CD-HPS has been evaluated in HPLC under multi-mode conditions via separating positional isomers of some disubstituted benzenes and enantiomers of some chiral drug compounds. The separation results show that P-CD-HPS exhibited excellent selectivity for separating the positional isomers of nitrophenol and nitraniline and the enantiomers of some chiral drug compounds. The hydroxyl residues of partially substituted β-cyclodextrin and chiral spacer linking to secondary hydroxyl site of the β-cyclodextrin in the P-CD-HPS not only have important contributions to chiral recognitions and separations, but also allow the P-CD-HPS to be used under multi-mode mobile-phase conditions in HPLC.

Novel SiO2‐Supported Chromocene and Vanadium Bimetallic Catalysts Producing Bimodal Polyethylene

AbstractPolyethylene (PE) with bimodal molecular weight distribution has intrigued researchers because of its significant processability and mechanical properties. Novel SiO2‐supported chromocene (S‐9)/vanadium (V) bimetallic catalysts utilizing the different hydrogen response for producing bimodal PE are successfully synthesized and studied systematically. The catalysts are prepared through using the residual hydroxyl groups on the surface of SiO2‐supported vanadium catalyst to introduce chromocene. Both of the low molecular weight (MW) fraction and the high MW fraction can be controlled through adjusting the loading of bimetallic active centers. The bimetallic catalysts also show good 1‐hexene incorporation ability in ethylene/1‐hexene copolymerization.

Relationship between starch liquefaction behavior and properties of polymer coated urea from liquefied starch

The relationship between starch liquefaction behavior and properties of coated urea was explored to give some insights into the optimized technical selection of bio-polyol for polymer coated urea. The liquefied corn starch was monitored for insoluble residue content, viscosity, acid value and hydroxyl value. Nitrogen release, water permeability and biodegradation properties of coating material were also studied. FTIR and 1H-NMR results revealed that alcoholysis, hydroxyalkylation and side reactions co-existed during the liquefaction process, and side reactions predominated as the process continued. It was found that re-condensation leading to the increase of polyester polyols was beneficial for subsequent coating of urea according to the nitrogen release and biodegradation performance. The selected bio-polyols derived from starch can be available to prepare polymer coated urea being more accordant with the nutrient requirement of plants at growth stages.

Exploration of Insulin Amyloid Polymorphism Using Raman Spectroscopy and Imaging

We aimed to investigate insulin amyloid fibril polymorphism caused by salt effects and heating temperature and to visualize the structural differences of the polymorphisms in situ using Raman imaging without labeling. The time course monitoring for amyloid formation was carried out in an acidic condition without any salts and with two species of salts (NaCl and Na2SO4) by heating at 60, 70, 80, and 90°C. The intensity ratio of two Raman bands at 1672 and 1657 cm−1 due to antiparallel β-sheet and α-helix structures, respectively, was revealed to be an indicator of amyloid fibril formation, and the relative proportion of the β-sheet structure was higher in the case with salts, especially at a higher temperature with Na2SO4. In conjunction with the secondary structural changes of proteins, the S-S stretching vibrational mode of a disulfide bond (∼514 cm−1) and the ratio of the tyrosine doublet I850/I826 were also found to be markers distinguishing polymorphisms of insulin amyloid fibrils by principal component analysis. Especially, amyloid fibrils with Na2SO4 media formed the gauche-gauche-gauche conformation of disulfide bond at a higher rate, but without any salts, the gauche-gauche-gauche conformation was partially transformed into the gauche-gauche-trans conformation at higher temperatures. The different environments of the hydroxyl groups of the tyrosine residue were assumed to be caused by fibril polymorphism. Raman imaging using these marker bands also successfully visualized the two- and three- dimensional structural differences of amyloid polymorphisms. These results demonstrate the potential of Raman imaging as a diagnostic tool for polymorphisms in tissues of amyloid-related diseases.

In2O3-x(OH)y/Bi2MoO6 S-scheme heterojunction for enhanced photocatalytic performance

Surface heterojunction engineering has been extensively studied to promote efficient charge separation in semiconductor materials. Designing an effective heterojunction system to optimize the separation and transport of photo-induced charges is an appealing strategy to enhance the photocatalytic efficiency. In this work, In2O3-x(OH)y in situ decorated Bi2MoO6 two-dimensional step-scheme heterojunctions were synthesized through a controlled dehydroxylation process of indium-based precursors. The charge transfer mechanism of this step-scheme heterojunctions was confirmed by the characterization of electron structures, reactive species, photoelectric properties and DFT theoretical calculation. The band bending and the internal electric field caused by the charge transfer upon hybridization can effectively promote the separation of charges and present the optimal redox capacity. In addition, surface residual hydroxyl groups can regulate the surface energy state and optimize the interfacial charge transfer kinetics of the prepared step-scheme heterojunction. Eventually, the step-scheme heterojunction exhibits superior performance in photocatalytic reduction of hexavalent chromium and degradation of organic pollutants under visible light irradiation. This work provides an innovative perspective to construct photocatalyst with superior activity.

Unique silica biomimetic mineralization of acidic elastin-like polypeptides without hydroxyl and charged residues

Elastin-like polypeptides (ELPs), usually as a purification-tag, can be easily expressed and rapidly purified. We found ELPs[V9F-40], which did not contain hydroxyl or charged residues with the pI of 5.52, could biomimetically form silica when they were in ordered structure. The specific activity of ELPs[V9F-40] was 70.89 ± 9.53. Besides, the time needed for the completion of biomimetic silicification was about 138 s, which was only 1/3 of that for other reported peptides. The ELPs@silica is mainly spherical and the sizes of them were around 900 nm. However, currently presented mechanisms for peptide-triggered silica biomimetic mineralization could not explain such unique phenomenon. It would pave a new way for mining or designing peptides with such function, which provide a potential green method for the preparation of biomimetic silica particles. It would endow ELPs more functions and expand the application fields of ELPs such as the bioinspired synthesis of peptide biotemplated metal or nonmetal oxide nanoparticles.

A New Dealcoholization Method in the Synthesis of Vinyl Methyl Phenyl Silicone Resins for LED Encapsulation

The oligosiloxane resins were synthesized through hydrolytic sol-gel reaction and remained many hydroxyl groups, which did great harm to the curing process and resulted in poor performance of the cured products. In previous works, epoxy-modified silicone resins were synthesized by dealcoholization, a reaction between 3-glycidoxypropylmethyldimethoxysilane and terminal hydroxyl groups in phenyl silicone resins. Although this method eliminated the hydroxyl groups, it caused a large loss of vinyl groups inevitably and a poor stability of cured products. In this study, methyltrimethoxysilane (MTMS) was used to eliminate hydroxyl groups containing in vinyl methyl phenyl silicone resins, which were synthesized through hydrolytic sol-gel reaction. Most of residual hydroxyl groups were deleted effectively and the great loss of vinyl groups were avoided in the dealcoholization reaction. Then, the methyl phenyl silicone materials were fabricated by hydrosilylation reaction between the synthesized vinyl methyl phenyl silicone resins and hydrogen-containing ones. The cured silicone materials showed excellent optical performance (~ 89.1% at 450 nm) and good adhesion performance. In addition, due to less vinyl loss in the vinyl methyl phenyl silicone resins, the cured methyl phenyl silicone materials exhibited higher cross-linking density, better thermal resistance (5% mass loss at 435 °C) and better mechanical properties (50 shore D) compared with the epoxy-modified phenyl silicone materials. The lumen depreciation (working 168 h at 50 mA) and reflow soldering tests further demonstrated the methyl phenyl silicone materials possessed good thermal stability. These results indicated that the methyl phenyl silicone materials could be used as a LED encapsulant with a good performance.