ZnS-超分子有机凝胶复合薄膜的制备及其传感性能

发布时间：2019-02-28 09:27

【摘要】：在环境检测中,胺类化合物毒性大,甚至具有很强的致癌作用,使其在环境和食品安全检测中备受关注。因此,人们迫切需要不断研究和开发检测胺类化合物的方法。目前,用于测定环境中胺类化合物的常规方法有气相色谱法、液相色谱法、质谱法、电化学法等,其中荧光方法由于其高灵敏度、高选择性、适用多参数测定等特性备受关注。加之薄膜传感器可重复使用、使用方便、不污染待测体系、易于器件化等优点,使得荧光薄膜传感器逐渐成为一类极具发展前景的功能薄膜材料。不同于荧光小分子,无机半导体纳米结构由于其激发光谱宽、发射光谱窄、发射波长可调、光学性能稳定等特点,使其作为传感元素在传感方面具有多种独特优势,而通过弱相互作用形成的超分子有机凝胶为制备结构更加丰富的纳米材料提供了新思路,本文预期通过改变超分子聚集体的结构调控无机纳米结构的形貌、粒径、尺寸分布等,进而改善其传感性能。基于上述考虑,本文以无机半导体纳米材料作为传感元素,超分子凝胶为成膜基质,利用小分子量有机胶凝剂对无机沉积反应的稳定、诱导、限域作用分别采用原位合成和共混法制备ZnS-超分子有机凝胶杂化薄膜。具体来讲,主要完成了以下工作:(1)采用含Zn(Ac)2的超分子有机凝胶薄膜为模板,室温条件下,向反应体系中缓慢引入足量的H2S气体,制备ZnS-超分子复合薄膜。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、紫外-可见光吸收光谱(UV-vis)、荧光光谱(PL)和荧光寿命(Lifetime)等手段对复合薄膜进行了表征。研究发现,胶凝剂聚集体结构直接决定着最终杂化薄膜的形貌,且网络结构的存在可有效防止纳米粒子进一步聚集;通过改变Zn(Ac)2的起始浓度可调节杂化薄膜中ZnS粒子的尺寸及含量,传感实验表明该薄膜对有机单胺和二胺类蒸汽表现出灵敏的选择性传感,且传感可逆性佳。(2)考虑到纳米材料不同制备方法对其纳米结构的影响,首先采用油水界面法制备得到ZnS纳米粒子,将其通过物理混合引入到超分子凝胶体系当中,室温干燥,待胶凝溶剂挥发干燥后得到复合薄膜。研究结果发现,ZnS纳米粒子为立方晶型;复合薄膜中ZnS纳米粒子分散均匀,且胶凝剂形成的网络结构能够很好地稳定ZnS微纳米粒子,表现为稳定的发光性能。此外还系统研究了复合薄膜中ZnS含量对其荧光强度以及胺类蒸汽传感性能的影响,结果表明薄膜中ZnS含量越高,荧光强度越强,对挥发性较强的有机单胺和二胺蒸汽越敏感,且传感可逆性良好。(3)考虑到掺杂金属离子对无机纳米材料发光行为的有效调控,本部分期望通过在ZnS纳米粒子中掺杂Mn2+,改善其发光性能,进而提高其对胺类气体的传感性能。首先采用油水界面法制备不同Mn2+掺杂量的ZnS:Mn纳米粒子,再将其通过物理混合的方式引入到超分子凝胶薄膜中,室温干燥。XRD结果表明,ZnS掺杂前后其晶型没有发生改变;不同Mn2+掺杂量的ZnS:Mn-超分子有机凝胶杂化薄膜静态荧光光谱表明,随着Mn2+掺杂量增大,ZnS的发射光谱逐渐红移,且杂化薄膜的荧光强度呈现先增强后减弱的变化规律,当Mn2+掺杂量为1.5%时,其荧光强度最大;传感性能实验表明,对于掺杂Mn2+的杂化薄膜对乙二胺的最大猝灭效率随着Mn2+掺杂量增大而减小,响应时间变短,灵敏度提高。
[Abstract]:In the environment detection, the amine compound has a large toxicity, and even has a strong carcinogenic effect, so that the amine compound has great attention in the environment and food safety detection. Therefore, there is an urgent need for a continuous study and development of methods for detecting amine compounds. At present, the conventional methods for determining the amine compounds in the environment include gas chromatography, liquid chromatography, mass spectrometry, electrochemical methods, and the like, wherein the fluorescence method is of great concern due to its high sensitivity, high selectivity, and the application of multi-parameter measurement. In addition, the thin-film sensor can be used repeatedly, is convenient to use, does not pollute the system to be tested, is easy to device and the like, and makes the fluorescent thin-film sensor gradually become a kind of functional film material with great development prospect. different from the fluorescent small molecule, the inorganic semiconductor nano-structure has the characteristics of wide excitation spectrum, narrow emission spectrum, adjustable emission wavelength, stable optical performance and the like, so that the inorganic semiconductor nano-structure has a plurality of unique advantages in the sensing aspect as a sensing element, The super-molecular organic gel, which is formed by weak interaction, provides a new idea for the preparation of a more abundant nano-material, and it is expected that the morphology, the particle size and the size distribution of the inorganic nano-structure can be controlled by changing the structure of the supramolecular aggregate, so as to improve the sensing performance. Based on the above considerations, the inorganic semiconductor nano-material is used as a sensing element, the super-molecular gel is a film-forming substrate, and the stability and the induction of the inorganic deposition reaction are induced by using a small-molecular-weight organic gelling agent, ZnS-supramolecular organic gel hybrid films were prepared by in-situ synthesis and co-mixing respectively. Specifically, the following steps are mainly completed: (1) a super-molecular organic gel film containing Zn (Ac)2 is adopted as a template, and a sufficient amount of H2S gas is slowly introduced into the reaction system under the condition of room temperature to prepare the ZnS-supramolecular composite film. The composite film was characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), ultraviolet-visible light absorption spectrum (UV-vis), fluorescence spectrum (PL) and fluorescence lifetime. The results show that the aggregate structure of the gelling agent directly determines the morphology of the final hybrid film, and the existence of the network structure can effectively prevent the further aggregation of the nanoparticles, and the size and the content of the ZnS particles in the hybrid thin film can be adjusted by changing the starting concentration of the Zn (Ac)2, The sensing experiments show that the film has sensitive and selective sensing on the organic monoamines and the diamine vapors, and the sensing reversibility is good. (2) taking into account the influence of different preparation methods of the nano material on the nano structure, firstly, the ZnS nano-particles are prepared by adopting an oil-water interface method, and the ZnS nano-particles are introduced into the super-molecular gel system through physical mixing, and the ZnS nano-particles are dried at room temperature, and the compound film is obtained after the gelling solvent is volatilized and dried. The results show that the ZnS nanoparticles are the cubic crystal form, the ZnS nanoparticles in the composite film are uniformly dispersed, and the network structure formed by the gelling agent can stably and stably stabilize the ZnS micro-nano particles, and the ZnS nanoparticles exhibit stable light-emitting performance. The results show that the higher the ZnS content in the film, the stronger the fluorescence intensity, the more sensitive to the volatile organic monoamines and the diamine vapor, and good sensing reversibility. (3) Considering the effective regulation of the light-emitting behavior of the inorganic nano-materials by doping the metal ions, the part of the invention is expected to improve the light-emitting performance by doping Mn2 + in the ZnS nano-particles, so as to improve the sensing performance of the amine-like gas. The preparation method comprises the following steps of: firstly, preparing the ZnS: Mn nano-particles with different Mn2 + doping amount by adopting an oil-water interface method, and then introducing the ZnS: Mn nano-particles into the super-molecular gel thin film by physical mixing, and drying at room temperature. The XRD results show that the crystal form of ZnS: Mn-supermolecular organic gel hybrid thin film has no change before and after ZnS doping. The static fluorescence spectra of ZnS: Mn-supermolecular organic gel hybrid thin film with different Mn2 + doping amount show that the emission spectrum of ZnS is gradually redshifted with the increase of Mn2 + doping. and the fluorescence intensity of the hybrid thin film is firstly enhanced and then weakened, and when the doping amount of the Mn2 + is 1.5 percent, the fluorescence intensity of the hybrid thin film is the most; and the sensing performance experiment shows that the maximum quenching efficiency of the hybrid thin film doped with the Mn2 + is reduced with the increase of the Mn2 + doping amount, The response time is shortened and the sensitivity is improved.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.2

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