Identification of Bioactivity,Volatile and Fatty Acid Profile in Supercritical Fluid Extracts of Mexican arnica

Supercritical fluid extraction (SFE) is a sustainable technique used for the extraction of lipophilic metabolites such as pigments and fatty acids. Arnica plant is considered a potential candidate material with high antioxidant and antimicrobial activities. Therefore, in this study, a locally available Heterotheca inuloides, also known as Mexican arnica, was analyzed for the extraction of high-value compounds. Based on different pressure (P), temperature (T), and co-solvent (CoS), four treatments (T) were prepared. A maximum 7.13% yield was recovered from T2 (T = 60 °C, P = 10 MPa, CoS = 8 g/min), followed by 6.69% from T4 (T = 60 °C, P = 30 MPa, CoS = 4 g/min). Some bioactive sesquiterpenoids such as 7-hydroxycadalene, caryophyllene and δ-cadinene were identified in the extracts by GC/MS. The fatty acid profile revealed that the main components were palmitic acid (C16:0), followed by linoleic acid (C18:2ω6c), α-linolenic acid (C18:3ω3) and stearic acid (C18:0) differing in percent yield per treatment. Antibacterial activities were determined by the agar diffusion method, indicating that all the treatments exerted strong antibacterial activity against S. aureus, C. albicans, and E. coli strains. The antioxidant capacity of the extracts was also measured by three in vitro assays, DPPH, TEAC and FRAP, using Trolox as a standard. Results showed high antioxidant capacity enabling pharmaceutical applications of Mexican arnica.     

Influence of Controlled Glucose Deprivation on Kinetics of Detoxification Mechanisms for Two Intermediate Metabolites, 9-Hydroxybenzo[a]pyrene and 3-Hydroxybenzo[a]pyrene,in 3T3 and RTG2 Cells

PAH metabolism is known to proceed in two successive steps the first one resulting in the production of activated metabolites which are subsequently transformed by the different pathways involved in the second step. Microspectrofluorometry enables the study of the kinetics of these steps on living intact cells in which no imbalance has been introduced artefactually. We have used this technique in order to check the influence of glucose deprivation on these kinetics. 9 and 3-OH-B(a)P have been selected as fluorescent substrates for there are potential substrates for the different pathways of the second step. The physiological cell status was controlled through the level of the intrinsic cellular fluorescence. Glucose deprivation results in a strong decrease of the experimental rate constants characteristic of the metabolism of 9 and 3-OH-B (a)P both in RTG2 and 3T3 cells. Nevertheless the metabolism of 3-OH-B(a)P in 3T3 cells appears to be less sensitive to glucose starvation, a result which remains to be explained.     

温度压力在废油再生分子蒸馏中的影响研究

通过单因素控制法进行分子蒸馏实验,利用油液检测设备得到不同温度压力下的再生油液部分理化指标。从色度8号的废油中得到色度4.5号的再生油液,根据方差分析和回归分析确定在210~240℃、30~90 Pa,再生油液运动粘度(y)和凝点(SP)与温度(T)、压力(P)的关系为SP=-23.594+0.018 6T-0.058 6T/P和y=19.181+0.038 9T-0.029P-0.208T/P。     

Pathogenic Mutations Shift the Equilibria of α‐Synuclein Single Molecules towards Structured Conformers

α‐synuclein (α‐Syn) is an abundant brain protein whose mutations have been linked to early‐onset Parkinson's disease (PD). We recently demonstrated, by means of a single‐molecule force spectroscopy (SMFS) methodology, that the conformational equilibrium of monomeric wild‐type (WT) α‐Syn shifts toward β‐containing structures in several unrelated conditions linked to PD pathogenicity. Herein, we follow the same methodology previously employed for WT α‐Syn to characterize the conformational heterogeneity of pathological α‐Syn mutants A30P, A53T, and E46K. Contrary to the bulk ensemble‐averaged spectroscopies so far employed to this end by different authors, our single‐molecule methodology monitored marked differences in the conformational behaviors of the mutants with respect to the WT sequence. We found that all the mutants have a much higher propensity than the WT to adopt a monomeric compact conformation that is compatible with the acquiring of β structure. Mutants A30P and A53T show a similar conformational equilibrium that is significantly different from that of E46K. Another class of conformations, stabilized by mechanically weak interactions (MWI), shows a higher variety in the mutants than in the WT protein. In the A30P mutant these interactions are relatively stronger, and therefore the corresponding conformations are possibly more structured. The more structured and globular conformations of the mutants can explain their higher propensity to aggregate with respect to the WT.     

Release characteristics of paracetamol and oleuropein from Mech-Degla date fruit tablets enriched and non-enriched with freeze-dried olive leaf extract

Release characteristics of paracetamol from date (Phoenix dactylifera L., var. Mech-Degla) fruit tablets enriched and non-enriched with freeze-dried olive leaf extract (OLE) were studied. For this, two types of tablets (T) were obtained by direct compression: (1) T1 from P1-powder blend, containing 60% date powder (DP) and 40% paracetamol, and (2) T2 from P2-powder blend, containing 57% DP, 40% paracetamol, and 3% OLE. The release of paracetamol was studied in phosphate buffer (pH?6.8) and HCl solution (0.1N). Additionally, the oleuropein released was investigated in the case of T2-tablets. Based on obtained results, P1- and P2-powder blends showed acceptable flow properties in terms of Hausner’s ratio (1.30, in the case of P2) and angle of repose for both P1 (31 degrees) and P2 (33 degrees). Dissolution study showed that the released paracetamol achieved 80% after 70?min, whereas the oleuropein release was almost complete after 30?min. On the other hand, the Peppas model described correctly dissolution kinetics of both paracetamol (R²=?0.99) and oleuropein (R²=?0.89) whatever the applied dissolution medium. Furthermore, the presence of OLE in T2-tablets enhanced their microbiological shelf-life.     

COMPARATIVE METABOLISM OF PHENANTHRO[3,4-B]THIOPHENE,PHENANTHRO[4,3-B]THIOPHENE AND THEIR CARBON ANALOG BENZO[C]PHENANTHRENE BY RAT LIVER MICROSOMES

Phenanthro[3,4-b]thiophene (P[3,4-b]T) and phenanthro[4,3-b]thiophene (P[4,3-b]T) are thiasters of weakly mutagenic benzo[c]phenanthrene (B[c]P). These polycyclic sulfur heterocycles (thia-PAHs) represent a group of chemicals which have been identified in cigarette smoke. P[3,4-b]T is a potent mutagen in Salmonella typhimurium strain TA100 in the presence of rat liver S9, whereas its isosteric isomer P[4,3-b]T is a nonmutagenic compound. In order to understand the mechanism underlying the differences in the mutagenic activity of P[3,4-b]T and P[4,3-b]T, we have investigated the metabolism of P[3,4-b]T, P[4,3-b]T, and their carbon analogue B[c]P by rat liver microsomes. The liver microsomes from rats treated with Aroclor 1254 metabolized P[3,4-b]T, P[3,4-b]T, and B[c]P at a rate nearly 7- to 9-fold greater than of the control liver microsomes. High-performance liquid chromatography (HPLC) analysis of the metabolites formed showed that B[c]P was metabolized almost exclusively to its dihydrodiols which comprised predominantly K-region diol as noted in the previous studies. Our preliminary studies on the metabolism of P[3,4-b]T, P[4,3-b]T and B[c]P by liver microsomes from control and Aroclor 1254-treated rats have shown a significant reduction in the formation of 6,7-diol (K-region diol) and 8,9-diol (diol with a bay-region double bond) of the two thia-PAHs compared to the formation of analogous 5,6-diol (K-region diol) and 3,4-diol (diol with a bay-region double bond) from B[c]P. Both P[3,4-b]T and P[4,3b]T produced a major, relatively nonpolar metabolite(s) (80–96% of total metabolites). These studies indicate that the highly mutagenic P[3,4-b]T is not metabolized to dihydrodiol with a bay-region double bond to any greater extent than the weakly or nonmutagenic B[c]P or P[4,3-b]T, suggesting that the metabolite(s) other than P[3,4-b]T8,9-diol is likely to be involved in the mutagenicity of P[3,4-b]T.     

Synthesis,structural, mechanical,and biological properties of HAp-ZrO2-hBN biocomposites for bone regeneration applications

Nowadays researchers are much interested in bioceramics for their use as biological implants. Researchers have succeeded to derive few bioceramic materials which show good biological response with living tissues. Few of the bioceramics are zirconia, hexagonal boron nitride and hydroxyapatite. Herein, the effects of zirconia nanoparticles and hexagonal boron nitride nanosheets in hydroxyapatite powder on the structural, mechanical, and biological properties were investigated. In this study, the formation of a potential composite with desired mechanical and biological properties is strongly anticipated. The present study is also proposed to provide further faces to improve osteogenic properties of the scaffolding material without altering the established mechanical and biological properties. Three different compositions in the system [(95-x)HAp-x(ZrO₂)-5hBN] (x = 10, 20, 30) were prepared using a simple solid-state reaction technique. In the samples, significant phase was identified for HAp [Calcium Phosphate Hydroxide: Ca₅(PO₄)₃(OH)]. SEM analysis of the composites revealed well-connected and uniform distribution of ZrO₂ and HAp nanoparticles on h-BN sheets. The composite samples 65H30Z5B9h (65HAp-30ZrO₂-5hBN sintered at 900 °C) and 65H30Z5B1T (65HAp-30ZrO₂-5hBN sintered at 1000 °C) showed improved mechanical and tribological behaviors. These samples exhibited excellent mechanical properties like compressive strength, Young's modulus, toughness and density. The obtained values were 2.154 MPa, 0.0182 MPa, 553.82 MJ/m³, 2.29 g/cm³ for 65H30Z5B9h and 3.798 MPa, 0.0832 MPa, 231.59 MJ/m³, 2.31 g/cm³ for 65H30Z5B1T respectively. Cytotoxicity of the composites was studied on Drosophila fly and Mice calvarial osteoblasts cells at five different concentrations. Toxic effect of the composite 65H30Z5B1T on the fly was confirmed by phenotypic observations, trypan blue staining, pupal count, and larval crawling speed. Composite 65H30Z5B1T was found to be toxic in this study, but the composite 65H30Z5B9h was not. Further, cell viability, alkaline phosphates, and mineralization tests confirmed non-toxic property and enhanced osteogenic activities for the composite sample 65H30Z5B9h.     

DNA甲基化对调控胰岛分化基因表达的影响

目的探讨DNA甲基化对调控胰岛分化基因表达的影响,为调控干细胞分化为胰岛细胞提供理论依据。方法采用甲基化DNA免疫共沉淀-实时定量PCR法(MeDIP-qPCR)检测129/J小鼠胚胎干细胞、NIT1细胞及NIH3T3细胞中Pdx-1、MafA、Nkx6.1和Oct4四种调控胰岛分化基因的DNA甲基化程度;同时采用实时定量RT-PCR检测上述3种细胞中4种基因mRNA表达水平,分析这些基因DNA甲基化水平差异与基因表达之间的关系。结果 Pdx-1、MafA和Nkx6.1基因在129/J小鼠胚胎干细胞和NIT1细胞中呈低甲基化,在NIH3T3细胞中则呈高甲基化,前两种细胞的甲基化程度明显低于后者(P<0.05);Oct4基因在129/J小鼠胚胎干细胞中未甲基化,在NIT1和NIH3T3细胞中呈低甲基化,NIT1细胞的甲基化程度明显低于NIH3T3细胞(P<0.05)。低甲基化的Pdx-1、MafA和Nkx6.1基因在NIT1细胞中可高效表达,而在NIH3T3和129/J小鼠胚胎干细胞中则未见表达(P<0.05);Oct4基因在129/J小鼠胚胎干细胞中可高效表达,在NIT1和NIH3T3细胞中则未见表达。结论转录起始区DNA甲基化程度可影响Pdx-1、MafA、Nkx6.1和Oct4基因的表达,参与β细胞的分化过程。     

Characterizations for blends of phosphorus-containing copolyester with poly(ethylene terephthalate)

High molecular weight phosphorus-containing copolyesters, poly(ethylene terephthalate)-co-poly(ethylene DDP) (PET-co-PEDDP)s, were prepared and characterized with the objective of producing a non-halogen flame retardant system for practical applications. The phosphorus-containing copolyester with 30 wt% phosphorus (P30 copolyester) was blended with PET to evaluate their characteristics and flame retardancy. Higher phosphorus content results in lower crystallinity and higher char formation after thermal degradation. The rheological behavior remains similar to that of PET. The P30/PET blend possesses higher crystallization rate than the corresponding phosphorus-containing copolyester containing equal phosphorus content. Thermal and rheological behaviors of P30/PET blends are similar to PET or the phosphorus-containing copolyesters. The P30/PET blends are miscible or compatible base on single T_gs detected by DSC or DMA. The SEM/EDX phosphorus mapping image of the P30/PET blend shows uniform distribution of the phosphorus moieties within the P30/PET matrix, another indication of a compatible or miscible blend between the phosphorus-containing copolyester P30 and PET. Flame retardancy of the P30/PET blend is identical to that of the phosphorus-containing copolyester with identical phosphorus content. Blending of high phosphorus content copolyester with virgin PET provides a feasible method to obtain a flame resistant PET with LOI greater than 28.     

Influence of 6-Amino chrysene on the Kinetics of the Metabolic Process for 9-Hydroxybenzo(a)pyrene in 3T3 and RTG2 Cells

PAH metabolism is known to proceed in two successive steps, the first one resulting in the production of activated metabolites which are subsequently transformed by the different pathways involved in the second step. Microspectrofluorometry enables us to study the kinetics of these steps in living intact cells in which no imbalance has been introduced artificially. We have used this technique in order to check the influence of 6-Amino-chrysene (6 AC) on the kinetics of the metabolism of 9-Hydroxybenzo(a)pyrene (9-OH-B(a)P) which, in a previous study, had been shown to proceed mainly through the glucuronide pathway. We have first demonstrated that both 6 AC and 9-OH-B(a)P were good substrates for Rabbit Glucuronic Transferase. Then using RTG2 and 3T3 cells, we have verified that the glucuronide pathway was strongly involved in the metabolism of 6 AC. Finally we have demonstrated that 6 AC strongly inhibits the metabolism of 9-OH-B(a)P in both cell lines. Such results are consistent with a competition of both compounds for the same binding site of GTAse 1.     

马丁－侯状态方程向固相发展

ＭＨ－８１状态方程式经过进一步改进后，其使用范围可扩展到固相。在该方程中增加了三个常数，Ａ６、Ｂ７和ｂｓ后变为：Ｐ＝ＲＴＶ－ｂ＋Ａ２＋Ｂ２Ｔ＋Ｃ２ｅ－５．４７５ＴＴｃ（Ｖ－ｂ）２＋Ａ３＋Ｂ３Ｔ＋Ｃ３ｅ－５．４７５ＴＴｃ（Ｖ－ｂ）３＋Ａ４＋Ｂ４Ｔ（Ｖ－ｂ）４＋Ｂ５Ｔ（Ｖ－ｂ）５＋Ａ６（Ｖ－ｂｓ）６＋Ｂ７Ｔ（Ｖ－ｂｓ）７改进后的状态方程对于一般物质，如二氧化碳、氩、甲烷及氮等，在三相点到临界点温度、计算的饱和液相、汽相摩尔体积与文献值的偏差基本上保持ＭＨ－８１方程的准确度，而固相摩尔体积的偏差在几千大气压下也在１０％左右，一般压力不太高时都在５％以内，需要增加的输入信息仅三相点（Ｐｔ，Ｔｔ）下的Ｖｓｔ数据。     

离子膜烧碱中氢氧化钠和碳酸钠含量的测定

介绍了双指示剂法和GB/T11199-89乙法(GB4348.1)的含量测定方法,提出了混合指示剂法和GB629-81两种新测定方法,并总结了化学试剂测定方法在离子膜烧碱中氢氧化钠和碳酸钠含量测定中的应用实践。     

Effect of heat treatment on corrosion and electrochemical behaviour of Mg-3Nd-0.2Zn-0.4Zr (wt.%) alloy

Corrosion behaviour of Mg-3Nd-0.2Zn-0.4Zr (NZ30K) alloy was investigated in as-cast (F), solution treated (T4) and peak-aged (T6) conditions in 5% NaCl solution by immersion test and electrochemical measurements. The results of immersion test show that the corrosion resistances of NZ30K alloy in three conditions are much higher than that of the commercial AZ91D ingot. NZ30K alloy exhibits better corrosion resistance in T4 temper than it does in the other two conditions due to the dissolution of cathodic compound and higher Nd content in α matrix. Although the corrosion products of NZ30K alloy have different morphologies in three conditions, all of them are compact and uniform. The corrosion product is identified as magnesium hydroxide by XRD. The potentiodynamic polarization curves show that the overpotentials of cathodic hydrogen evolution reaction on NZ30K-T4 and NZ30K-T6 are much higher than on NZ30K-F, and the anodic curves are characterized by clear current plateaus due to the protective corrosion film formed on the surface of the alloy. The results of EIS also confirm that the heat treatment is beneficial to the improvement of the corrosion resistance for NZ30K alloy.     

SBS/P(St-MMA)热塑性互穿聚合物网络结构与力学性能

采用原子转移自由基聚合(ATRP)法合成了苯乙烯一甲基丙烯酸甲酯共聚物[P(St-MMA)]。采用分步法制备了SBS／P(St-MMA)热塑性互穿聚合物网络(TIPN)。研究了P(St-MMA)质量分数、MMA／St(摩尔比,下同)和不同聚合方式对TIPN结构和力学性能的影响。结果表明：生成了具有较窄相对分子质量分布的P(St-MMA);P(St-MMA)质量分数在30％,左右时,采用ATRP法制备的SBS／P(St-MMA)TIPN拉伸强度和扯断伸长率达到最大;随MMA／St增加,TIPN拉伸强度增大,扯断伸长率不变。常规自由基聚合法制备的TIPN与ATRP法相比,前者相对分子质量高,相对分子质量分布宽,拉伸强度高,扯断伸长率随P(St-MMA)质量分数增加而下降。     

Physiological Stress Responses,Fecal Marking Behavior,and Reproduction in Wild European Pine Martens (<Emphasis Type="Italic">Martes martes</Emphasis>)

The relationship among physiological stress responses, fecal marking behavior, and reproduction in male and female European pine martens was investigated. Between July 2004 and June 2007, 145 fresh fecal samples were collected in a protected area of northwest Spain. Fecal DNA was used for specific identification by using the polymerase chain reaction-restriction fragment length polymorphism technique. Glucocorticoids (cortisol) and sex steroid hormones (P, progesterone; E, estradiol; T, testosterone) were quantified by enzyme immunoassays. Sex was assigned according to concentrations of T+P+E and the T/P ratio. Fecal cortisol concentrations were higher in males than in females. Feces with a presumptive marking function (on conspicuous substrates, above ground level, and/or in latrines) had higher mean levels of cortisol than those that were on inconspicuous substrates and/or at ground level, for both males and females. Fecal mark density was highest in spring, when mean levels of fecal cortisol were more elevated. Therefore, the higher physiological stress levels in females could be due to female physiological state (late-term pregnancy and lactation), competition for resources connected to birth, or food resources for offspring rearing. In males, the increase could be due to higher male competition for access to females during pro-estrus and estrus. Our results suggest that scent marking in European pine martens is related to reproduction and is involved in intersexual and intrasexual communication.     

Hypercholesterolemia Negatively Regulates P2X7-Induced Cellular Function in CD4+ and CD8+ T-Cell Subsets from B6 Mice Fed a High-Fat Diet

We have previously showed that plasma membrane cholesterol and GM1 ganglioside content are responsible for the opposite sensitivity of mouse leukemic T cells to ATP. We also reported that the sensitivity of CD4⁺ and CD8⁺ T cells to ATP depends on their stage of differentiation. Here, we show that CD4⁺ and CD8⁺ T cells from B6 mice express different levels of membrane GM1 and P2X7 but similar levels of cholesterol. Thus, in CD4⁺ T cells, membrane cholesterol content negatively correlated with ATP/P2X7-induced CD62L shedding but positively correlated with pore formation, phosphatidylserine externalization, and cell death. By contrast, in CD8⁺ T cells, cholesterol, GM1, and P2X7 levels negatively correlated with all these ATP/P2X7-induced cellular responses. The relationship between cholesterol and P2X7-induced cellular responses was confirmed by modulating cholesterol levels either ex vivo or through a high-fat diet. Membrane cholesterol enrichment ex vivo led to a significant reduction in all P2X7-induced cellular responses in T cells. Importantly, diet-induced hypercholesterolemia in B6 mice was also associated with decreased sensitivity to ATP in CD4⁺ and CD8⁺ T cells, highlighting the relationship between cholesterol intake and the amplitudes of P2X7-induced cellular responses in T cells.     

Toughness-Curve Behavior of an Alumina-Mullite Composite

Toughness-curve ( T - or R -curve) behavior of a composite of 30 vol%, polycrystalline, coarse-grained, spherical alumina agglomerates dispersed throughout a fine-grained, 50/50 vol% alumina-mullite matrix, and that of its microstructural end-members (100% matrix and 100% alumina), were studied using the indentation-strength-in-bending technique. T -curves were deconvoluted from indentation-strength data using an indentation fracture mechanics model. The monolithic matrix and alumina exhibited an invariant toughness and a moderate T -curve, respectively. In comparison, the composite exhibited a pronounced T -curve. The T -curve of the composite is best explained as deriving from the interaction of a propagating crack with the alumina agglomerates: crack propagation experiments revealing two possible toughening mechanisms-intra-agglomerate frictional grain bridging and elastic bridging ligaments in the matrix that appeared to be associated with alumina agglomerates. Rule-of-mixtures toughness calculations indicated that intra-agglomerate bridges could account for only a fraction of the toughening exhibited by the composite. It is suggested that the extra toughening arises from the elastic bridging ligaments.     

Intracerebral Administration of a Ligand-ASO Conjugate Selectively Reduces α-Synuclein Accumulation in Monoamine Neurons of Double Mutant Human A30P*A53T*α-Synuclein Transgenic Mice

α-Synuclein (α-Syn) protein is involved in the pathogenesis of Parkinson’s disease (PD). Point mutations and multiplications of the α-Syn, which encodes the SNCA gene, are correlated with early-onset PD, therefore the reduction in a-Syn synthesis could be a potential therapy for PD if delivered to the key affected neurons. Several experimental strategies for PD have been developed in recent years using oligonucleotide therapeutics. However, some of them have failed or even caused neuronal toxicity. One limiting step in the success of oligonucleotide-based therapeutics is their delivery to the brain compartment, and once there, to selected neuronal populations. Previously, we developed an indatraline-conjugated antisense oligonucleotide (IND-1233-ASO), that selectively reduces α-Syn synthesis in midbrain monoamine neurons of mice, and nonhuman primates. Here, we extended these observations using a transgenic male mouse strain carrying both A30P and A53T mutant human α-Syn (A30P*A53T*α-Syn). We found that A30P*A53T*α-Syn mice at 4–5 months of age showed 3.5-fold increases in human α-Syn expression in dopamine (DA) and norepinephrine (NE) neurons of the substantia nigra pars compacta (SNc) and locus coeruleus (LC), respectively, compared with mouse α-Syn levels. In parallel, transgenic mice exhibited altered nigrostriatal DA neurotransmission, motor alterations, and an anxiety-like phenotype. Intracerebroventricular IND-1233-ASO administration (100 µg/day, 28 days) prevented the α-Syn synthesis and accumulation in the SNc and LC, and recovered DA neurotransmission, although it did not reverse the behavioral phenotype. Therefore, the present therapeutic strategy based on a conjugated ASO could be used for the selective inhibition of α-Syn expression in PD-vulnerable monoamine neurons, showing the benefit of the optimization of ASO molecules as a disease modifying therapy for PD and related α-synucleinopathies.     

Über das Kationen-Bindevermögen des 1-5-Elektrolyten Na5P3O10 in verdünnten wäßrigen Lösungen bei Anwendung osmotischer und konduktometrischer Messungen I

Studies on Cation Binding Properties of 1-5-Electrolyte - Na₅P₃O₁₀ - in Dilute Aqueous Solutions by Using Osmotic and Conductometric Measurements The “practical stoichiometrical” activity coefficients of pentasodiumtriphosphate (T.P.) were calculated from the osmotic measurements of the dilute aqueous solutions. Also in the case of T.P. a functional relationship exists between the activity coefficient and the cation binding property. The electrical conductivity measurements of the aqueous solutions of T.P. mixed with NaCl, KCl and CaCl₂ show a purely electrostatic action in the T.P. ? (1-1)-electrolyte interaction and in the case of CaCl₂ ? T.P. interaction in the range < 0.6 mmol T.P./1 a defined reaction involving complex formation. This complex is decomposed rapidly with increasing T.P. concentration so that even this binding is preferentially of electrostatic nature.     

Structure characterization of sulfuric acid-doped poly(3-octylthiophene)

The structures of sulfuric acid-doped and water-undoped poly(3-octylthiophene) (P30T) were investigated by gel permeation chromatography (GPC), elemental analysis (EA), conductivity measurement, ultraviolet-visible-near-Infrared spectroscopy (UV-Vis-near-IR), Electron spin resonance (ESR), infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). For H₂SO₄-doped P3OT, the counter ion is HSO₄ ^– and the positive charge formed on the main chain distributes only on the conjugated C-C bond and does not distribute on the S atoms. The conductivity is found to increase by 5 orders as the doping level is 0.22. After the undoping with water, C-OH groups are formed on the main chains, which results in a decrease in conjugating length and in a less order chain arrangement. The undoped P3OT film can be redoped by 98% H₂SO₄; however, the doping level is less than its original value at the same doping condition.