聚酯/无机杂化分子间键合作用及微结构相关性的光谱研究

采用FTIR,UV-Vis,WAXD和DSC手段,研究了分子间为非共价键化学结合的PCL／SiO2高分子-无机杂化透明材料组分间的键合型式;分子间特殊氢键相互作用行为与结晶性聚合物在杂化材料中的微结构相关性。结果表明,杂化体系中PCL高分子与SiO2无机组分间的键合,主要是依赖于杂化体系中较强的分子间氢键相互作用,其作用强度随无机相TEOS含量而变化。体系中氢键相互作用增加使PCL结晶高分子的相对结晶度下降,杂化材料的光学透明性提高。同时对体系中高分子-无机组分的微相分离尺度产生影响。     

交联淀粉微球酶降解过程的FTIR和XRD分析

以可溶性淀粉为原料,N,N′-亚甲基双丙烯酰胺为交联剂,采用反相悬浮聚合得到了一种交联淀粉微球(CSM)。为了深入了解交联淀粉微球(CSM)的降解过程,利用傅里叶变换红外光谱(FTIR)和X射线粉末衍射(XRD) 等光谱分析手段,对可溶性淀粉、CSM及其CSM在模拟肠液中不同时间的降解产物进行了分析。FTIR和SEM的研究结果表明, CSM在消化液中3 h内可稳定维持其交联结构,降解后3和12 h之间1 090 cm-1处的C—O—C弯曲振动峰减弱,酰胺的Ⅰ带吸收峰和Ⅱ带吸收峰强度的减弱说明了淀粉分子链被降解, 交联结构开始解聚,12 h后酰胺的Ⅰ带吸收峰和Ⅱ带吸收峰完全消失,说明交联结构已完全被除去;XRD结果表明,CSM在消化液中降解12 h后的情况与可溶性淀粉的降解情况相似,非结晶性部分被分解,结晶度随降解过程的进行而提高,但是仍然小于可溶性淀粉的结晶度。     

PET与SAN/PAN复合膜界面的 FTIR-ATR研究

应用傅里叶衰减全反射红外光谱(FTIR-ATR)技术对聚对苯二甲酸乙二酯(PET)表面形成不同厚度的超薄苯乙烯-丙烯腈共聚物(SAN)和聚丙烯腈(PAN)的共混物膜及其SAN/PAN共混物膜的厚度、界面层PET亚甲基的构像变化等进行研究,结果表明PET表面共混物膜的厚度随共混物混合液中SAN含量的增加而增加,界面层成膜物质与基材的分子链段间发生了相互渗透和扩散,分子链的极性越相近,越容易成膜.对PET红外光谱吸收峰的A1340/A1410进行定量研究表明,在成膜过程中,PET分子链的亚甲基构像由反式向旁式转变,引起界面层PET的结晶度降低.FTIR-ATR是分析复合膜界面层结构信息的有效方法.     

多胺型纤维素基螯合纤维的合成和光谱学研究

将漂白化学桉木浆(BCEP)与甲基丙烯酸缩水甘油酯(GMA)的接枝共聚产物(CPGMA)与乙二胺(EDA)反应,合成了多胺型纤维素基螯合纤维CPGMA-EDA。利用傅里叶变换红外光谱(FTIR)、固体核磁共振碳谱(13C CP/MAS NMR)和X射线衍射(XRD)对产物进行了分析。FTIR和13C CP/MAS NMR的研究结果表明,与EDA反应后,CPGMA在904 cm-1波数处的环氧基特征吸收峰基本消失,3 200～3 500 cm-1处的吸收峰因新增N—H伸缩振动而明显增宽,说明大量氨基通过开环反应被接枝到了CPGMA表面;XRD结果表明所得纤维素基螯合纤维的结晶度为48.1%,相对于原漂白化学桉木浆的结晶度下降了31.0%,说明反应不仅发生在纤维素的非结晶区,同时也发生在结晶区。     

有机官能团的太赫兹光谱特征研究

采用傅里叶远红外光谱仪(FTIR),在室温条件下测量了多种饱和直链有机小分子的太赫兹光谱。测试结果显示,有机官能团的差异导致有机物的太赫兹光谱特征显著不同。其中,有机物的晶格振动吸收峰和分子间氢键的振动吸收峰分别位于太赫兹高频和低频波段。而且,饱和直链一元醇的—OH官能团产生的分子间氢键的特征峰位于57 cm-1,而三十烷酸的—COOH官能团产生的分子间氢键的特征峰则位于74 cm-1。分子间氢键使三十烷醇和三十烷酸对太赫兹辐射的吸收能力明显地强于三十烷烃。相比于三十烷醇,三十烷酸的太赫兹特征峰还发生有规律的红移和蓝移现象。此外,还采用密度泛函理论B3LYP/6-311G(d, p)基组对饱和直链烷烃、烷醇和烷酸的太赫兹光谱进行了仿真计算,发现分子间氢键作用越强的有机物的单体分子的仿真结果与实测光谱的吻合程度越低。二聚体结构的仿真结果与实测光谱的吻合程度明显地高于单分子结构。研究结果对利用FTIR研究其他有机官能团的太赫兹光谱特征、探索有机分子内部的振动模式、探究有机物太赫兹响应的物理原理及器件应用等具有重要意义。     

同步扫描光谱方法研究聚合物结晶动力学过程

固体表面反射光与其折射指数之间存在余弦函数关系,而折射指数的均方起伏又和固体表面的密度和浓度起伏有关。因此从反射光的变化可以反映材料内部结构的一些变化。基于此理论指导,本文利用同步扫描光谱(SSS)方法,即荧光光谱仪的同步扫描模式进行反射光的检测,成功地监测了聚己内酯(PCL)薄膜在铜片上的熔融和非等温结晶过程。PCL薄膜的SSS谱图出现了两个明显的荧光光谱仪的光源峰(467和473 nm),利用这两个峰的信息可以表征聚合物的熔融和结晶过程中分子链结构的变化。采用SSS方法表征分析得到了PCL的热动力学和结晶动力学参数,其结晶Avrami exponent n为2.8～3.2,平均值为3.1,表明PCL的非等温结晶遵循异相成核、三维球晶生长机理。这些与差示扫描量热仪(DSC)得到的参数一致。研究结果表明SSS方法是一种简单、有效的原位测试聚合物熔融和结晶动态过程的方法。此外,SSS方法是一种基于荧光光谱仪的具有普适性的光谱方法,对发光和不发光固态聚合物均可以检测研究。     

二氰胺根分子内费米振动耦合能量转移的超快二维红外光谱

二氰胺根离子(N(CN)-2,DCA)的C≡N对称及反对称伸缩振动(νas,C≡N和νss,C≡N)和N—C伸缩振动的和频峰(νas,N—C+νss,N—C)之间由于费米共振作用存在振动耦合。本文研究了二氰胺钠在DMSO溶液中的超快二维红外(2DIR)光谱和超快红外泵浦探测(IR PP)光谱。结合该体系的傅里叶变换红外(FTIR)光谱实验结果,对二氰胺根离子体系中的分子内振动能量转移过程进行了分析。     

水性涂料施工过程中微观结构的FTIR研究

以市售立邦水性涂料作为研究对象,溶剂水作为变量因子。配制不同水料比的涂料系列样品,分别用FTIR/ATR、FTIR/漫反射光谱表征湿料、涂膜的微观结构特征,湿料抽滤得到的固型物用FTIR/漫反射光谱表征。分析其官能团变化情况,研究施工过程,溶剂对涂膜的影响。结果显示：随着加水量的增加,湿料的FTIR/ATR光谱中,1 727 cm-1对应的羰基吸收峰,逐渐转为肩峰,871 cm-1吸收峰发生蓝移,峰强度逐渐减弱;涂膜的漫反射红外图谱,3 400 cm-1的—OH吸收峰、3 030 cm-1不饱和—CH吸收峰强度逐渐变弱,2 962和2871 cm-1的甲基和亚甲基的吸收峰强度逐渐增强,2 516 cm-1吸收峰位移至2 603 cm-1形成肩峰,1 647 cm-1吸收峰逐渐位移至1 455 cm-1,1 107 cm-1对应的C—O伸缩振动吸收峰发生红移。在水性涂料施工过程中,溶剂水与涂料分子间存在相互作用,对涂层分子中电子云的密度分布有显著的影响,此结果对涂料的生产及施工有参考意义。     

超声方法对纤维素超分子结构的影响

探讨了在超声技术处理纤维素过程中,纤维素材料的超分子结构发生的变化。结果显示,经超声波处理过的纤维素（Ⅰ）的分子间氢键、结晶度、晶粒尺寸及晶粒形态都有一定的变化．FTIR分析说明,经超声处理后,其分子间氢键减弱、结晶度提高．X-射线衍射分析证实,超声处理产物仍保持纤维素材料原有的晶型和两相（晶区与非晶区）共存的微细结构．     

PVP对Nylon 6形貌及结晶行为影响的研究

采用变温红外光谱、示差扫描量热（DSC）和偏光显微镜（POM）等方法研究了聚乙烯吡咯烷酮（PVP）与尼龙6（nylon 6）分子间的相互作用及其对nylon 6热行为及结晶形貌的影响。DSC结果表明PVP的加入明显影响了nylon 6的熔融和结晶行为：随着PVP含量增加,PVP/nylon 6共混物的结晶温度、熔融温度及结晶度均逐渐降低;POM观察显示：随着PVP含量增多,nylon 6的球晶尺寸变小、球晶逐渐变得不完善。变温红外光谱结果表明,无定形PVP分子的羰基能够与nylon 6分子的N—H基团形成新的氢键,部分破坏了nylon 6分子之间的氢键结构,从而阻碍了nylon 6分子的规整排列,使其结晶度降低并导致nylon 6结晶形貌的变化。     

聚(偏氟乙烯-三氟乙烯)纳米薄膜极化反转与疲劳特性

采用旋涂法制备了厚度为140 nm的聚(偏氟乙烯-三氟乙烯)[P(VDF-TrFE)]纳米薄膜, 研究了不同退火温度以及环境相对湿度对薄膜的极化反转和疲劳性能的影响. 运用X射线衍射仪、扫描电子显微镜和傅里叶变换红外光谱仪等测试技术对薄膜的微结构进行了表征. 实验结果表明, 通过不同温度的退火处理, P(VDF-TrFE)铁电薄膜的结晶度随着退火温度的升高而不断提高, 并且一定的温度范围内的退火处理可以提高薄膜的极化性能; 此外, P(VDF-TrFE) 铁电薄膜性能还表现出一定的环境湿度的敏感特性, 这与薄膜的物理性能和结构特点密切相关; P(VDF-TrFE)铁电薄膜在不同的环境湿度条件下 表现出较好的电学特性, 其漏电流均保持在10 ^-7A/cm² 的较低水平. 本工作揭示了再退火过程对薄膜的极化反转速度和疲劳恢复特性的影响, 并结合薄膜二次疲劳结果, 探讨了薄膜可逆的内部疲劳恢复特性机理.     

氮化硅粉末的傅里叶变换红外光谱研究

利用透射法和漫反射法,研究了纯氮化硅粉末和KTBr烯释后样品的红外光谱特征,比较了不同方法获得得的红外光谱的异同,实验发现,纯氮化硅粉末的曼反射光谱在约1200cm^-1处出现一尖锐的强峰,而KBr稀释样品的透光谱和温反射光谱不出现此峰,研究认为,该峰对应氮化硅颗粒表面Si-O键的振动。     

The comparison between CdS thin films grown on Si(111) substrate and quartz substrate by femtosecond pulsed laser deposition

Two kinds of cadmium sulfate (CdS) thin films have been grown at 600 °C onto Si(111) and quartz substrates using femtosecond pulsed laser deposition (PLD). The influence of substrates on the structural and optical properties of the CdS thin films grown by femtosecond pulsed laser deposition have been studied. The CdS thin films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), photoluminescence (PL) and Raman spectroscopy. Although CdS thin films deposited both on Si(111) and quartz substrates were polycrystalline and hexagonal as shown by the XRD , SEM and AFM results, the crystalline quality and optical properties were found to be different. The size of the grains for the CdS thin film grown on Si(111) substrate were observed to be larger than that of the CdS thin film grown on quartz substrate, and there is more microcrystalline perpendicularity of c-axis for the film deposited on the quartz substrate than that for the films deposited on the Si substrate. In addition, in the PL spectra, the excitonic peak is more intense and resolved for CdS film deposited on quartz than that for the CdS film deposited on Si(111) substrate. The LO and TO Raman peaks in the CdS films grown on Si(111) substrate and quartz substrate are different, which is due to higher stress and bigger grain size in the CdS film grown on Si(111) substrate, than that of the CdS film grown on the amorphous quartz substrate. All this suggests that the substrates have a significant effect on the structural and optical properties of thin CdS films. PACS 81.15.Fg; 81.05.Ea; 78.20.-e; 78.67.-n; 42.62.-b     

Raman spectra and XPS studies of phase changes in Ge2Sb2Te5 films

Ge_2Sb_2Te_5 film was deposited by RF magnetron sputtering on Si (100) substrate. The structure of amorphous and crystalline Ge_2Sb_2Te_5 thin films was investigated using XRD, Raman spectra and XPS. XRD measurements revealed the existence of two different crystalline phases, which has a FCC structure and a hexagonal structure, respectively. The broad peak in the Raman spectra of amorphous Ge_2Sb_2Te_5 film is due to the amorphous －Te－-Te－ stretching. As the annealing temperature increases, the broad peak separates into two peaks, which indicates that the heteropolar bond in GeTe_4 and the Sb－Sb bond are connected with four Te atoms, and other units such as (TeSb) Sb－Sb (Te_2) and (Sb_2) Sb－Sb (Te_2), where some of the four Te atoms in the above formula are replaced by Sb atoms, remain in crystalline Ge_2Sb_2Te_5 thin film. And from the results of Raman spectra and XPS, higher the annealing temperature, more Te atoms bond to Ge atoms and more Sb atoms substitute Te in (Te_2) Sb－Sb (Te_2).     

Surface plasmon polaritons assisted diffraction in metal films with subwavelength hole array

Metal films grown on Si wafer have been perforated with a periodic hole array and anomalous enhanced transmission in the subwavelength regime has been observed. High-order transmission peaks up to Si(2,2) are clearly revealed due to the large dielectric constant of Si against that of the air. Si(1,1) peak splits into two branches at oblique incidence both in TE and in TM polarization, which confirms that anomalous enhanced transmission is a surface plasmon polaritons (SPPs) assisted diffraction phenomenon.     

退火温度对富硅氮化硅薄膜发光特性和结构的影响

采用直流等离子体增强化学气相沉积(PECVD)法在(100)单晶硅片表面生长富硅氮化硅薄膜,研究了不同的退火温度对氮化硅薄膜发光性质和结构的影响。研究发现,随着退火温度的升高,氮化硅薄膜的发光强度逐渐减弱,发光是由缺陷能级引起的,在900 ℃时荧光基本消失。XPS测试表明,在N₂氛围900 ℃下退火,氮化硅薄膜中未有硅相析出,故未表现出硅量子点的发光。FTIR测试也为PL结论提供了一定的证据。     

Deposition of ZnS thin film by ultrasonic spray pyrolysis: effect of thickness on the crystallographic and electrical properties

Zinc sulfide (ZnS) thin films have been deposited on Si (1 0 0) substrate using ultrasonic spray pyrolysis. X-ray diffraction (XRD) analysis revealed that the films are (0 0 2) preferentially oriented with c-axis-oriented wurtzite structure. The crystallinity has been found to improve with film thickness in the 180–6000 nm range. Film structure has been analyzed by XRD, scanning electron microscope, FTIR, and Raman spectroscopies, while the stoichiometry has been verified by energy-dispersive spectroscopy and particle-induced X-ray emission techniques. Electrical properties of the grown films were characterized by current–voltage and capacitance–voltage measurements where, the films show better conducting behavior at higher thickness.     

On the Degree of Crystallinity from DSC in the Case of Multiple Melting of Synthetic Polymers

Considering the well‐known phenomenon of multimelting peak of crystalline polymers, it has been demonstrated that for calculating the degree of crystallinity using the heat of fusion, all the melting peaks observed have to be accounted for regardless of their origin‐recrystallization or presence of different crystalline modifications.     

CVD法制备硅基氮化镓薄膜

利用化学气相沉积法(CVD),分别以三氧化二镓(Ga₂O₃)和氨气(NH₃)为镓源和氮源在硅衬底合成了一种由片状微晶构成的氮化镓(GaN)薄膜,实验中没有使用缓冲层。通过场发射扫描电子显微镜(FESEM)、电子能量散射谱(EDS)、X射线衍射(XRD)、高分辨电镜(HRTEM)和光致发光谱(PL)对样品进行分析,生成物为质量较好的富镓的纯氮化镓薄膜。片状氮化镓微晶表面大小约数百纳米,厚度数十纳米,薄膜表面平整、致密,没有裂纹或龟裂现象,与Si衬底结合紧密。氮化镓薄膜的带边峰位于367nm处,同时出现了黄光发射峰。并对此种氮化镓薄膜的生长机理进行了探讨。     

Cobalt-induced polycrystalline silicon film growth

Cobalt (Co)-induced crystalline silicon (Si) growth was investigated. The Co catalyst reacted to dc magnetron sputtered Si at 600 °C forming a Co silicide layer. The polycrystalline Si (poly-Si) was epitaxially grown above the Co silicide template, which has a small lattice misfit to Si. Annealing followed to improve the Si crystallinity. X-ray diffraction was performed to trace Co silicide phase formation and transition. The Co-rich silicide phase transitioned to CoSi₂ by annealing. The crystallinity of Si films was identified using reflection absorption Fourier transform-infrared spectroscopy, which detected unique peaks at 689 and 566 cm⁻¹ after the annealing process. The thin poly-Si film was used to fabricate a Schottky diode to prove the electronic quality. A good quality Si thin film was achieved by the metal-induced Si growth.