共查询到19条相似文献,搜索用时 171 毫秒
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原位复合材料的微观形态 总被引:1,自引:0,他引:1
将热塑性树脂聚砜与4种自制的热致液晶聚合物熔融共混,制备原位复合材料,采用了3种制样方法:①毛细管直接法;②单螺杆直接挤出法;③先用混合机混合均匀,再用单螺杆挤出。研究了液晶聚合物的分子结构、分子量、含量以及加工方法对原位复合材料微观形态的影响。结果发现,液晶聚合物分子链的刚性越大,其取向成纤性越好;对同一液晶聚合物而言,其分子量越大,则成纤性越好;在其它条件相同时,液晶聚合物含量越少,则所形成的纤维直径越细;3种制样方法中,第三法最佳,用此法可得分布均匀且取向性好的微纤。 相似文献
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具有高对比度的快速响应聚合物分散液晶(PDLC)膜 总被引:1,自引:0,他引:1
通过对制膜材料的选择和制膜条件的精确控制,制备了具有高对比度的快速响应聚合物分散液晶膜。本文给出了实验结果并进行了简单的讨论。 相似文献
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考察了熔融挤出后施加的牵伸比和增容剂对聚丙烯 (PP)/热致液晶聚合物(TLCP) 原位复合材料中TLCP分散相形貌的影响。结果表明,复合材料中的TLCP相随着牵伸比的增大逐渐形成良好的微纤结构,TLCP微纤的长径比随牵伸比增大而增大;当体系中加入增容剂PP-g-MAH后,体系中TLCP在较小的牵伸速率下即可形成长径比很大的微纤结构。将上述所得原位复合材料与玻纤在 200℃(低于TLCP熔融温度) 下熔融挤出制得玻纤和液晶聚合物微纤混杂增强的材料。实验证明,在此加工温度下液晶聚合物形态得到较好保持,注射样品中不存在原位复合材料中典型的"皮-芯"形貌。同时,增容剂PP-g-MAH还明显改善了玻纤与基体之间的界面粘结。 相似文献
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聚合物分散液晶相分离及其膜的光电特性 总被引:1,自引:0,他引:1
通过选择适宜的制膜材料及采用光聚合的用引发相分离法对制膜条件(如光强、温度等)的精确控制,实现了聚合物具有三维网络结构的相分离基体膜。由液晶分子形成的向列液晶微粒被独立地分散在基体网络内。这种薄膜具有15V的饱合驱动电压,30个以上的对比度,几个毫秒的响应速度。 相似文献
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侧链型偶氮聚合物液晶的光致取向 总被引:2,自引:0,他引:2
侧链型偶氮聚合物液晶是一种新型光子材料,在光信息存储和光开关等领域有重要的应用前景,近几年来,这方面的研究工作发展迅速,已成为聚合物液晶领域中新的生长点,文中对偶氮聚合物液晶光致取向各方面的研究成果进行了概要分析,对其研究进展和发展趋向进行了综述。 相似文献
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介晶单体十一烯酸胆甾醇酯(M1)和手性单体丙烯酸薄荷醇酯(M2)通过接枝共聚引入聚甲基含氢硅氧烷(PMHS)中,制得系列侧链聚合物P1~P8。通过DSC、偏光显微镜(POM)、X射线衍射分析(WAXD,SAXS)、旋光仪等手段对聚合物进行了表征。聚合物P1~P8都具有光学活性,均为胆甾型热致液晶,具有较宽的介晶相范围,呈现出清晰的彩色Grand—jean织构及油丝织构。但当M2含量大于30%时,聚合物的液晶性能逐渐变弱。 相似文献
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液晶热固性聚合物的研究进展 总被引:2,自引:0,他引:2
本文就液晶热固性聚合物的研究现状进行了概述。着重对液晶环氧树脂、液晶聚氨酯、液晶芳香族聚酯及丙烯酸酯类,液晶热固性有机硅聚合物,液晶热固性聚酰亚胺的研究进展作了介绍。 相似文献
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溶致液晶材料在水中会形成聚合物,聚合物的长度会随着温度而改变,因此可以通过改变溶液的温度来改变聚合物的长度,从而在一定的温度和浓度范围内产生液晶相.研究了一种名为蓝色27的阴丹酮衍生物(C28-H18O10N4C12)的溶致液晶材料.实验发现,20℃时封装在玻璃盒中的浓度为4.5%的蓝色27水溶液样品的透光率随着搁置时间的延长明显增加,计算结果表明,样品的有序度会随着时间的延长而增加,这种增加与系统中聚合物长度随着搁置时间变长有关. 相似文献
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Using coupled-mode theory combined with the transfer matrix method, this paper presents the impact of fibre grating parameters(grating period, grating length and average index modulation) and the separation between long-period fibre grating and fibre Bragg grating (FBG) on the reflection spectra of cascaded long-and short-period grating (CLBG). Two grating periods and two grating lengths have only impact on the two reflection peaks. The two resonance wavelengths shift towards the longer wavelength when the period of FBG decreases. Further, we study the sensing characteristics of coated CLBG. By analysing the relationship between the refractive index sensitivity and the thin film parameters (film refractive index and film thickness), the optimized parameters for the coated CLBG used as film sensor were obtained. Data simulation shows that the resolution of the refractive index of this coated CLBG film sensor is predicted to be 10?6. This implies that the coated CLBG has an important application value in sensing and measurement field. 相似文献
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Tomas Tamulevi?ius Rimas Šeperys Mindaugas Andrulevi?ius Vitoldas Kopustinskas Šarūnas Meškinis Sigitas Tamulevi?ius 《Thin solid films》2011,519(12):4082-4086
In this work we present an optical refractive index (RI) sensor based on the spectral analysis of anomalies in the optical response from the diffraction grating employing polarized polychromatic light. The sensor consists of holographic diffraction grating (period 423.5 nm) coated with a thin (110 nm) SiOx doped diamond like carbon film (DLC) that defines sensitivity of the sensor as well as the range of the spectral analysis. The deposition of the DLC film (synthesized by the direct ion beam deposition from the hydrocarbon source) has influence on the shape but not on the position of the anomalies observed in the specular reflection spectrum. From the reflection spectra the RI dispersion curve of liquid analyte-water was obtained. 相似文献
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Characterization of optically switchable holographic polymer-dispersed liquid crystal transmission gratings 总被引:1,自引:0,他引:1
This study characterizes the all-optical switching effect in holographic polymer-dispersed liquid crystal transmission gratings. The light-induced switching behaviors of these structures are due to the doped azobenzene-derived LC (azo-LC), which changes the refractive index of phase-separated LC within the polymer composite. This study also optimizes the polymer-dispersed liquid crystal formulation containing 15 wt.% azo-LC and 35 wt.% nematic LC to achieve a grating performance with a tunable diffraction efficiency of 78% and a fast switching-on time (0.5 s) with a relatively small light stimulus of 9 mW/cm2. 相似文献
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Real-time diffraction efficiency is measured during hologram formation in undeveloped dichromated gelatin (DCG) film. The main features of real-time diffraction efficiency of undeveloped DCG reveal double peaks with increasing exposure time. Adopting the grating translation technique, we show that the first peak originates from the absorption grating and that the latter is related to the phase grating. To explain such complicated hologram-formation dynamics, we present a phenomenological model for mixed gratings associated with photoinduced refractive-index changes and absorption changes. We have compared the model results with the experimental results, which show good agreement. 相似文献
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利用多极法对包层空气孔为正六边形对称结构光子晶体光纤的模式场进行了分析,计算出不同波长下基模的有效折射率,结合使用模式耦合理论和传输矩阵法对基于光子晶体光纤的布拉格光栅特性进行了计算和仿真,对比了常规单模光纤所成光栅与相同光栅周期的光子晶体光纤布拉格光栅反射谱及时延特性之间的差异.在此基础上,对光纤光栅的切趾特性进行了研究,选择不同的切趾函数,得出最佳切趾函数下光栅传输谱.理论计算和仿真结果表明,随波长增加,基模有效折射率下降,光栅谐振波长出现蓝移,采用啁啾化处理后,10 cm长光子晶体光纤光栅可以提供1 200 ps以上的线性时延. 相似文献
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Hydrogen sensor based on side-polished fiber Bragg gratings coated with thin palladium film 总被引:1,自引:0,他引:1
A new type of hydrogen sensor based on a side-polished fiber Bragg grating (FBG) coated with thin palladium film was demonstrated experimentally. The used FBG with the reflectivity of 90% is fabricated in a hydrogen-loaded single-mode fiber (SMF-28) by using the phase mask writing technique of a KrF excimer laser. The experimental results show that proposed sensor can be applied for hydrogen concentration measurements. 相似文献
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采用溶胶凝胶法,在FTO(SnO2:F)低辐射镀膜玻璃衬底上制备了柱状晶体结构的TiO2薄膜,获得双层结构FTO/TiO2镀膜玻璃样品.研究了TiO2薄膜厚度对FTO/TiO2镀膜玻璃样品的光催化活性、低辐射性能以及透光性能的影响.结果表明,FTO/TiO2镀膜玻璃样品光催化活性随着TiO2薄膜厚度的增加先升高后下降,在TiO2薄膜厚度为300 nm时光催化活性最佳;低辐射性能随着TiO2薄膜厚度的增加而下降,但TiO2薄膜厚度为300 nm时仍然具备一定的低辐射性能;透光性能与TiO2薄膜膜厚的关系不大,可见光透射比保持在72%左右;表面平均粗糙度约为1 nm,表面光滑,不易沾染油污灰尘.该镀膜玻璃在保证低辐射建筑节能和透光的前提下,兼具光催化自清洁功能,具有很好的应用前景. 相似文献