智能型AMPS/DMAEMA水凝胶的电敏感性能

以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)和甲基丙烯酸N,N-二甲氨基乙酯(DMAEMA)为单体,N,N′-亚甲基双丙烯酰胺为交联剂,过硫酸铵和亚硫酸氢钠为氧化还原引发剂,采用水溶液聚合法制备了AMPS/DMAEMA水凝胶,考察了样品水凝胶在外加直流电场刺激下的消溶胀动力学和弯曲行为.结果表明,DMAEMA单体含量和施加电压大小对水凝胶的电敏感性能有着显著影响.用一级动力学方程能够较好地描述水凝胶在接触电压刺激下的消溶胀过程.在非接触电压刺激下,单体摩尔比,n(AMPS):n(DMAEMA)=9:1的水凝胶向负极弯曲;单体摩尔比n(AMPS):n(DMAEMA)=5:5的水凝胶向正极弯曲;单体摩尔比n(AMPS):n(DMAEMA)=7:3的水凝胶随着非接触电压的增大,出现先向负极弯曲,后向正极弯曲的现象.     

聚丙烯酰胺/聚甲基丙烯酸(2-甲基氨基)乙酯高强度双网络水凝胶的制备及pH响应性

利用两步法合成了聚丙烯酰胺(PAM)/聚甲基丙烯酸(2-甲基氨基)乙酯(PDMAEMA)双网络水凝胶,第一网络为锂藻土(Laponite)物理交联的PAM纳米复合水凝胶,第二网络为化学交联剂N,N-亚甲基双丙烯酰胺(BIS)交联PDMAEMA。研究了2种网络相对含量、纳米黏土Laponite用量、化学交联剂BIS用量对水凝胶强度和pH响应性的影响。研究结果表明,PAM/PDMAEMA双网络水凝胶具有高强度,改变单体AM和DMAEMA的配比、交联剂的用量,其拉伸强度在36～91.9 kPa范围内可调。PAM/PDMAEMA双网络水凝胶还具有灵敏的pH刺激响应性,在pH=4时双网络水凝胶溶胀度急剧下降。     

温度敏感性聚甲基丙烯酸N,N-二甲基氨基乙酯(PDMAEMA)水凝胶的合成及性能研究

采用热化学聚合法制备了聚甲基丙烯酸N,N-二甲基氨基乙酯(PDMAEMA)水凝胶,并对其溶胀性能进行了研究.研究结果表明,PDMAEMA水凝胶具有温度敏感性,在去离子水中其ICST约为50℃;水凝胶的温度敏感性与介质的pH值有关,在碱性溶液中凝胶表现出典型的温度敏感性,而在酸性溶液中凝胶的溶胀率受温度的影响很小,没有温度敏感性.     

N-异丙基丙烯酰胺对软接触镜材料性能的影响

以0.2%的2-羟基-甲基苯基丙烷-1-酮(1173)为引发剂,0.5%的二乙二醇甲基丙烯酸酯(EGDM A)为交联剂,常温下用紫外灯合成了N-异丙基丙烯酰胺(N IPAm)/甲基丙烯酸2-羟基乙酯(HEM A)/N-乙烯吡咯烷酮(NVP)三元共聚物;与相同条件下合成的HEM A/NVP共聚物进行了试验对比。凝胶在水中的溶胀实验证明,含N IPAm的三元共聚物溶胀率对温度的敏感性强于HEM A-NVP共聚物;傅立叶红外光谱与热重测试显示了两种材料的结构差异。     

NVP/HEMA/RMA共聚水凝胶溶胀性能研究

采用本体聚合法,制备了N-乙烯基吡咯烷酮(NVP)/甲基丙烯酸羟乙酯(HEMA)、NVP/HEMA/EMA(甲基丙烯酸乙酯)和NVP/HEMA/BMA(甲基丙烯酸丁酯)3种不同的共聚水凝胶材料,并用重量法和TG法研究了这3种不同组成水凝胶的溶胀性能.研究结果表明:加入疏水性单体甲基丙烯酸酯类,共聚水凝胶溶胀性能下降,由于EMA与HEMA结构相似,相容性好,其对溶胀性能的影响比BMA的影响小.     

PEG/HEMA水凝胶复合支架的制备及其溶胀性能

以偶氮二异丁腈(AIBN)为引发剂,N,N'-亚甲基双丙烯酰胺(BIS)为交联剂,采用自由基聚合法合成了聚乙二醇(PEG)/甲基丙烯酸β-羟乙酯(HEMA)复合凝胶.采用冷冻干燥法制备凝胶支架,结果表明,凝胶支架具有多孔结构,为水分子的进出提供了路径和代谢物通道;随着交联剂用量的增大,水凝胶的平衡含水量降低;凝胶的平衡含水量随着温度的升高而下降,离子强度的增加使水凝胶的溶胀度降低.     

P(AM-co-AMPS)基凝胶的溶胀动力学研究

本文以丙烯酰胺(AM)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为有机单体、正硅酸乙酯(TEOS)为无机原料合成了P(AM-co-AMPS)基水凝胶,研究了凝胶的相转变温度,以及在相转变温度前后的溶胀性能和溶胀动力学。结果表明,P(AM-co-AMPS)凝胶在25℃水温下主要以大分子松弛为主的溶胀方式,而在0℃水温下为Fickian扩散方式,且具有一定的温敏性;P(AM-co-AMPS)/SiO2杂化凝胶在0℃和25℃均保持非Fickian扩散方式,且温敏性被掩盖。     

N-羟甲基丙烯酰胺/丙烯酸智能水凝胶的合成及性能研究

以N-羟甲基丙烯酰胺(N-MAM)和丙烯酸(AA)为聚合单体,过硫酸铵(APS)和N,N,N′,N′-四甲基乙二胺(TEMED)为引发体系,N,N-亚甲基双丙烯酰胺(MBA)为交联剂采用自由基水溶液聚合法合成了p(N-MAM-co-AA)水凝胶。研究了APS、MBA的用量、单体浓度与单体配比、溶液pH值和温度对水凝胶溶胀性能的影响,同时还研究了凝胶的溶胀-退溶胀动力学。     

离子液体聚合胶体晶体的制备及性能

以N,N-亚甲基双丙烯酰胺为交联剂,先通过光引发聚合制备聚丙烯酰胺水凝胶内嵌聚苯乙烯胶体晶体的聚合胶体晶体(PCC),再将PCC与氯化1-烯丙基-3-甲基咪唑离子液体进行溶剂置换,制备了离子液体聚合胶体晶体(ILPCC)。采用反射光谱研究了制备过程中聚合胶体晶体结构的变化,考察了ILPCC的压力响应性和压缩性能。研究表明,离子液体使胶体晶体的带隙先蓝移后红移,达到平衡时带隙红移220 nm以上。离子液体显著改善了聚合胶体晶体的存储稳定性和压缩性能,为制备干态光子晶体提供了新途径。     

通过高温自由基聚合合成耐热聚甲基丙烯酸甲酯树脂

本文探究了采用乙醇作溶剂,通过高温自由基聚合方法合成耐热甲基丙烯酸甲酯(MMA)与甲基丙烯酰胺(MAAM)共聚物的可行性,研究了聚合温度对Poly(MMA-co-MAAM)共聚物的共聚组成、相对分子质量、相对分子质量分布及共聚物耐热性的影响。结果表明,用乙醇作溶剂,聚合温度在90~120℃范围内可以成功合成高耐热Poly(MMA-co-MAAM)共聚物,其最佳共聚合温度为110℃。在此温度条件下合成的Poly(MMA-co-MAAM)共聚物的相对分子质量分布指数均小于1.5,耐热性最佳,其玻璃化转变温度较同等聚合条件下合成的PMMA均聚物高46℃。     

原子吸收测定酸雨钾,钠,钙,镁干扰因素探讨及其消除

主要讨论了用原子吸收分光光度法测定酸雨K、Na、Ca、Mg中主要阴离子AC-、NO3-、CIO4-、C1-、SO42-、PO43-F-对测定的干扰和采用硝酸锶做为干扰抑制剂的最佳使用浓度。结果表明:AC-<10.0mg/L、CIO4-<10.0mg/L、C1-<15.0mg/L、F-<10.0mg/L对K、Na、Ca、Mg测定无干扰;酸雨中含有大于0.50mg/L的PO34-、NO3-就可降低钙的吸光度,但含量达10.0mg/L也不影响K、Na、Mg的测定;含有大于0.50mg/L的SO24-对钙镁的测定都有抑制作用,且随着干扰物浓度的提高吸光值有变小的趋势,选择0.5%硝酸锶可消除以上干扰。     

Plasmid DNA-loaded asymmetrically porous membrane for guided bone regeneration

Although bone defects can be restored spontaneously,bone reconstruction with sufficient strength and volume continues to be a challenge in clinical practices.In recent years,the use of a variety of biomaterials with bioactivity has been attempted to compensate for this limitation.Herein,we fabricated a pDNA(encoding for BMP-2)-loaded asymmetrically porous polycaprolactone(PCL)/Pluronic F127 membrane as a bioactive guided bone regeneration(GBR)membrane,using a modified immersion-precipitation method.It was observed that the GBR membrane allows continuous release of pDNA for more than20 weeks.The pDNA was sufficiently transfected into human bone marrow stem cells(h BMSCs)without significant cytotoxicity and the gene-transfected cells showed prolonged synthesis of BMP-2.From in vitro osteogenic differentiation and in vivo animal studies,the effective induction of osteogenic differentiation of h BMSCs and enhanced bone regeneration by the pDNA-loaded asymmetrically porous PCL/Pluronic F127 membrane was observed,suggesting that the pDNA-loaded membrane as a bioactive GBR membrane can be an alternative therapeutic technique for effective bone regeneration.     

EuSr2RuCu2O8的超导电性和磁性

研究了铁磁性超导体EuSr2RuCu2O8的结构、超导电性和磁性。结果表明,该化合物为欠掺杂超导体,其超导转变起始温度为Tc^jonset=35K,零电阻温度为Tc(ρ=0)=10K,铁磁转变居里温度为Tc=130.2K。     

PVP对溶剂热合成FeS2(Pyrite)的形貌控制研究

采用溶剂热合成技术,以FeSO4和(NH2)2CS为反应前驱物,在聚乙烯吡略烷酮(PVP)作表面活性剂的醇-水体系中获得了晶粒完整的FeS2(Pyrite)粉体.借助X射线衍射(XRD)和透射电镜(TEM)对合成样品的晶相组成、分散性、形貌进行了分析与表征,结果表明,以PVP为表面活性剂可以显著提高产物的分散性,适当调节PVP的用量可以有效调控FeS2晶体的大小与形貌.     

Selective photocatalytic oxidation of steroid estrogens in water treatment: urea as co-pollutant

The objective of the present research concerns the competitive photocatalytic oxidation (PCO) and adsorption of steroid estrogens (SEs) on titanium dioxide in presence of urea. The results showed the indifference of SEs towards the presence of urea in concentrations characteristic for the domestic sewage. The selective PCO of SEs appeared to be feasible in alkaline media, in which the PCO exhibited the highest efficiency. Ethanol used for hydrophobic SEs dissolution in water appeared to be interfering with the PCO.     

The Adsorption of Gelatin by Suspended Solids and the Mechanism of Flocculation

Previous work on the adsorption of gelatin from solution onto the surface of suspended solids is reviewed in the light of recent theoretical and practical investigations on the adsorption of synthetic high polymers. The sensitization and protection of gold sols, and the mechanism of flocculation of suspensions with gelatin is discussed.     

Synergistically Accelerating Adsorption-Electrocataysis of Sulfur Species via Interfacial Built-In Electric Field of SnS2-MXene Mott–Schottky Heterojunction in Li-S Batteries

Developing efficient heterojunction electrocatalysts and uncovering their atomic-level interfacial mechanism in promoting sulfur-species adsorption-electrocatalysis are interesting yet challenging in lithium-sulfur batteries (LSBs). Here, multifunctional SnS₂-MXene Mott–Schottky heterojunctions with interfacial built-in electric field (BIEF) are developed, as a model to decipher their BIEF effect for accelerating synergistic adsorption-electrocatalysis of bidirectional sulfur conversion. Theoretical and experimental analysis confirm that because Ti atoms in MXene easily lost electrons, whereas S atoms in SnS₂ easily gain electrons, and under Mott–Schottky influence, SnS₂-MXene heterojunction forms the spontaneous BIEF, leading to the electronic flow from MXene to SnS₂, so SnS₂ surface easily bonds with more lithium polysulfides. Moreover, the hetero-interface quickly propels abundant Li⁺/electron transfer, so greatly lowering Li₂S nucleation/decomposition barrier, promoting bidirectional sulfur conversion. Therefore, S/SnS₂-MXene cathode displays a high reversible capacity (1,188.5 mAh g⁻¹ at 0.2 C) and a stable long-life span with 500 cycles (≈82.7% retention at 1.0 C). Importantly, the thick sulfur cathode (sulfur loading: 8.0 mg cm⁻²) presents a large areal capacity of 7.35 mAh cm⁻² at lean electrolyte of 5.0 µL mg_s⁻¹. This work verifies the substantive mechanism that how BIEF optimizes the catalytic performance of heterojunctions and provides an effective strategy for deigning efficient bidirectional Li-S catalysts in LSBs.     

纳米二氧化钛的光致发光

利用改进的溶胶－凝胶法制备了锐钛矿型二氧化钛的纳米粉末（４～１５ｎｍ）,测量了ＴｉＯ２的漫反射光谱（ＤＲＳ）和光致发光谱（ＰＬ）。结果表明,ＴｉＯ２纳米微粒的光学禁带宽度为３８４ｎｍ,在２５０～４００ｎｍ的紫外光范围内有强吸收;纳米二氧化钛在波长为４２０,４６１,４８５,５３０,５７３和６０９ｎｍ有强发光带,这些发光带分别为自由激子发光、束缚激子发光以及缺陷能级和表面态引起的发光。     

On the optical, structural, and morphological properties of ZrO2 and TiO2 dip-coated thin films supported on glass substrates

This article reports the optical and morphological properties of dip-coated TiO₂ and ZrO₂ thin films on soda-lime glass substrates by metal-organic decomposition (MOD) of titanium^IV and zirconium^IV acetylacetonates respectively. Thermogravimetric and differential thermal analysis (DTA–TG) were performed on the precursor powders, indicating pure TiO₂ anatase and tetragonal ZrO₂ phase formation. Phase crystallization processes took place in the range of 300–500 °C for anatase and of 410–500 °C for ZrO₂. Fourier Transform Infrared Spectroscopy (FT-IR) was used to confirm precursor bidentate ligand formation with keno-enolic equilibrium character. Deposited films were heated at different temperatures, and their structural, optical and morphological properties were studied by grazing-incidence X-ray Diffraction (GIXRD) and X-Ray Photoelectron Spectroscopy (XPS), Ultraviolet Visible Spectroscopy (UV-Vis), and Atomic Force Microscopy (AFM) respectively. Film thinning and crystalline phase formation were enhanced with increasing temperature upon chelate decomposition. The optimum annealing temperature for both pure anatase TiO₂ and tetragonal ZrO₂ thin films was found to be 500 °C since solid volume fraction increased with temperature and film refractive index values approached those of pure anatase and tetragonal zirconia. Conditions for clean stoichiometric film formation with an average roughness value of 2 nm are discussed in terms of material binding energies indicated by XPS analyses, refractive index and solid volume fraction obtained indirectly by UV-Vis spectra, and crystalline peak identification provided by GIXRD.     

甲基丙烯酸-2-羟基乙酯-co-N-乙烯-2-吡咯烷酮水凝胶结构及溶胀行为研究

为探讨甲基丙烯酸-2-羟基乙酯（HEMA）-co-N-乙烯-2-吡咯烷酮（NVP）共聚物水凝胶薄膜的溶胀性能,以2-羟基-甲基苯基丙烷-1-酮（1173）为光引发剂,二乙二醇甲基丙烯酸酯（DEGDMA）为交联剂,用紫外灯在室温下合成不同配比的HEMA-co-NVP共聚物薄膜。FTIR证实了共聚反应,热重（TG）测试显示薄膜结构中易分解的组分含量随着单体NVP含量的增加而增加。共聚物溶胀实验结果表明：随着交联剂含量的增加,水凝胶平衡溶胀率（EWC）下降;随着单体NVP含量的增加,材料的EWC上升,共聚水凝胶的溶胀过程趋于Case-Ⅲ型;随着温度的升高,材料的EWC降低,溶胀过程趋向Fick溶胀。