本文選題：銀納米顆粒 + 液相化學(xué)還原�。� 參考：《江蘇科技大學(xué)》2015年碩士論文

【摘要】：本文采用液相化學(xué)還原法和紫外光照化學(xué)還原法制備出手性銀納米粒子,并對銀納米粒子的手性傳導(dǎo)路徑和形成內(nèi)在機(jī)理初步探討和分析。用人體必需氨基酸之一的組氨酸作為手性誘導(dǎo)劑和穩(wěn)定劑,冰水新制NaBH4作為快速還原劑,還原前驅(qū)體AgNO3,制備組氨酸包裹的銀納米粒子。對得到的銀納米溶膠用紫外-可見吸收光譜、圓二色光譜、透射電鏡等方法對銀納米粒子進(jìn)行表征。分析了組氨酸與銀離子摩爾比、pH值對銀納米粒子穩(wěn)定性和手性信號的影響。當(dāng)溶液的pH=11.5,組氨酸/Ag+摩爾比為5:1時,制備得到的銀納米粒子的形貌近似于圓球形,在水溶液中單分散性良好,粒子的平均粒徑在10 nm左右。銀納米粒子的圓二色譜信號受溶液D,L-組氨酸/Ag+摩爾比影響較大,隨著摩爾比的增大,CD信號強(qiáng)度逐漸增強(qiáng),并在長波方向出現(xiàn)新的科頓效應(yīng)(Cotton effect)峰。向制備出的銀納米溶膠中加入氯化鈉溶液,促使單分散的銀納米粒子聚集,并討論了該方法制備的銀納米粒子的穩(wěn)定性。采用液相化學(xué)還原法,以脫氧膽酸鈉作為手性誘導(dǎo)劑和保護(hù)劑,pH=5.0的脫氧膽酸鈉水溶液陳化1d后,用新制的NaBH4還原Ag+制備了脫氧膽酸鈉包裹的銀納米粒子。制備的銀納米粒子粒徑約為20 nm,被脫氧膽酸鈉包裹的銀粒子通過超分子作用力聚集并吸附在生成的脫氧膽酸棒狀聚集體的表面,形成了一種有機(jī)/無機(jī)復(fù)合結(jié)構(gòu)。聚集在脫氧膽酸表面的銀納米粒子之間發(fā)生相互作用,使銀納米粒子的CD信號在其表面等離子體共振(SPR)區(qū)域表現(xiàn)為裂分的科頓效應(yīng)(Cotton effect)峰。溶液的pH值對制備的銀納米粒子的手性信號有明顯的影響,隨著溶液pH值的降低,制備的銀納米粒子的CD信號強(qiáng)度逐漸增強(qiáng)。采用紫外光照還原法,用膽酸鹽脫氧膽酸鈉當(dāng)做納米粒子的手性誘導(dǎo)劑以及防團(tuán)聚穩(wěn)定劑,溶液中的前驅(qū)體AgNO3被紫外燈照射后被還原,生成單質(zhì)銀聚集形成銀納米粒子,同時脫氧膽酸鈉被氧化。實驗結(jié)果表明隨著溶液pH值的提高,紫外光化學(xué)還原反應(yīng)的速度明顯增大。隨著光照還原時間的增加,相應(yīng)的CD光譜信號強(qiáng)度不斷變大。
[Abstract]:In this paper, the liquid phase chemical reduction method and ultraviolet light chemical reduction method were used to prepare the silver nanoparticles. The chiral conduction pathway and formation mechanism of silver nanoparticles were preliminarily discussed and analyzed. Using histidine, one of the essential amino acids, as chiral inducer and stabilizer, NaBH4 was prepared by using ice water as rapid reductant to reduce the precursor Agno _ 3 to prepare silver nanoparticles coated with histidine. The silver nanoparticles were characterized by UV-Vis absorption spectra, circular dichroism spectra and transmission electron microscopy. The effects of pH value of the molar ratio of histidine to silver ion on the stability and chiral signal of silver nanoparticles were analyzed. When the pH value of the solution is 11.5 and the molar ratio of histidine / Ag is 5:1, the morphology of the prepared silver nanoparticles is approximately spherical, and the monodispersity is good in aqueous solution, and the average particle size is about 10 nm. The circular dichroism (CD) signal of silver nanoparticles is greatly affected by the molar ratio of DnL- histidine / Ag, and the intensity of CD signal increases gradually with the increase of the molar ratio, and a new cotton effecteffect peak appears in the long wave direction. Sodium chloride solution was added to the silver nanoparticles to promote the aggregation of monodisperse silver nanoparticles. The stability of silver nanoparticles prepared by this method was discussed. Silver nanoparticles coated with sodium deoxycholate were prepared by liquid phase chemical reduction with sodium deoxycholate as chiral inducer and pH 5.0 sodium deoxycholate solution aged for 1 day. The silver nanoparticles prepared were about 20 nm in diameter. The silver particles encapsulated by sodium deoxycholate were assembled by supramolecular force and adsorbed on the surface of deoxycholic acid rod aggregates to form an organic / inorganic composite structure. The interaction between silver nanoparticles aggregating on the surface of deoxycholic acid makes the CD signal of silver nanoparticles present in the surface plasmon resonance (SPR) region of silver nanoparticles as the cotton effecteffect of split fraction. The pH value of the solution has an obvious influence on the chiral signal of the silver nanoparticles prepared. With the decrease of pH value of the solution, the CD signal intensity of the silver nanoparticles prepared increases gradually. Using sodium deoxycholate as chiral inducer of nanoparticles and anti-agglomeration stabilizer, the precursor AgNO3 in solution was reduced by ultraviolet lamp to form silver nanoparticles. At the same time, sodium deoxycholate was oxidized. The experimental results show that the rate of UV photochemical reduction increases with the increase of pH value of the solution. With the increase of light reduction time, the intensity of CD spectrum signal increases continuously.
【學(xué)位授予單位】：江蘇科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB383.1;O614.122

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