本文的具体研究工作及取得的研究 结果主要有以下三个方面: 首先采用自由基溶液聚合法合成了由N-异丙基丙烯酰胺和N-羟甲基丙烯酰胺共聚形成的具有温度响应性的聚合物PNN,然后 在不使用还原剂和表面活性剂等小分子化合物的情况下,通过紫外光 原位还原PNN 水溶液中溶解的AgNO 3,制得含AgNPs 的纺丝液。最 万方数据 东华大学硕士学位论文 摘要 III 后采用静电纺丝技术并结合热处理工艺制备了载AgNPs 的杂化纳米 纤维膜(AgNPs/PNN 膜)。电子显微分析结果表明,AgNPs/PNN 无规排列的、粗细均匀的纳米纤维组成,其平均直径随着配制纺丝液的AgNO 用量的增加从525nm下降到421 nm。粒径约4 nm的AgNPs 均匀地分布在纳米纤维中,其大小与AgNO 用量关系不大。浸泡在水中的AgNPs/PNN 膜在400 rpm 速度下震荡2 小时,质量损失小于 2%,表明它在水介质中有良好的稳定性。当水介质温度从25 升高 到50 ,AgNPs/PNN膜的面积收缩率为约50%,相转变温度在38 左右;如果将该膜循环浸泡于25和50 水介质中,其响应温度变 化达到溶胀平衡或消溶胀平衡的时间小于15 s,说明AgNPs/PNN 制得的AgNPs/PNN膜对4-硝基硫酚与NaBH 之间发生的氧化还原反应具有催化活性,其中AgNPs 含量越高,膜的催化活性越 强。该膜的催化活性与反应温度之间有明显的依赖关系,当反应温度 升高引起膜发生相转变时,其催化活性发生下降,因此通过调节温度 可达到控制反应速率的目的。另外,AgNPs/PNN 膜作为催化剂具有 良好的稳定性和可回收利用性。 制得的AgNPs/PNN膜可用作无支撑的SERS 基底,其SERS 活性随着膜中负载的AgNPs 含量的增加而提高。用该膜作为SERS 基底检测水溶液中微量的4-硝基硫酚,检出限小于10 -12 M,且检测 结果具有良好的重复性。AgNPs/PNN 膜的SERS 活性具有明显的温 度依赖性,在35~40 温度范围内,其SERS 活性随着温度上升而 万方数据 东华大学硕士学位论文 摘要 IV 显著增加,因此可通过升高温度来提高检测灵敏度。另外,用该膜作 为SERS 基底,可监测到4-硝基硫酚与NaBH 发生氧化还原反应的中间产物4,4’-二巯基偶氮苯,由此推断出该反应的机理,且发现中间 产物的生成速度决定着整个反应的快慢。 关键字:智能杂化纳米纤维膜,银纳米粒子,温度响应性,催化活性, 表面增强拉曼散射,基底,静电纺丝,原位监控反应 万方数据 东华大学硕士学位论文 摘要 II STUDYOF SILVER NANOPRTICLES LOADED TEMPERATURE STIMULUSRESPONSIVE HYBRID NANOFIBROUS MEMBRANE ABSTRACT Silver nanoparticles (AgNPs) lessthan 10 nm particle diameter hold strong catalytic activity surfaceenhanced Raman scattering (SERS) efficiency, so haveattractive application prospect SERSsubstrate. However, smallsize easilyoxidized due veryhigh surface energy. effectiveapproach loadthem specificcarrier. intelligenthydrogel carrier, self-aggregationcan propertiescan externalstimulus. previouslyreported intellligent hydrogel carriers stimulusresponsive bulky hydrogels formerhas much slower stimulus response, laterusually exists colloidalparticles aqueousmedium, suffering from poor colloidal stability thesis,fast temperature-responsive hybrid nanofibrous membrane macroscopicmechanical strength temperature-responsivehybrid nanofibous membrane fabricated electrospinningtechnique followed heattreatment process can intelligentrecyclable catalyst free-standingintelligent SERS substrate. membranehas real-timeSERS monitoring intermediate product itscatalyzed reaction reactionmechanism. obtainedresearch results followingthree aspects: temperature-responsivepolymer poly (N-isopropylacrylamide-co-N- hydroxymethylacrylamide) (PNN) firstlysynthesized via free radical copolymerization N-isopropylacrylamide(NIPAM) N-hydroxymethylacrylamide(NMA). spinningsolution containing silver nanoparticles (AgNPs) reducingAg PNNaqueous solution via ultraviolet irradiation 365nm usingsmall molecule compounds like reductant, 万方数据 东华大学硕士学位论文 摘要 III stabilizer organicsolvent. AgNPsloaded temperature-responsive hybrid nanofibrous membrane (AgNPs/PNN membrane) electrospinningtechnique, followed heattreatment process. resultsobtained scanningelectron microscopy transmissionelectron microscopy show AgNPs/PNNmembrane consists randomlyaligned nanofibers homogeneousdiameters, averagediameter decreasedfrom 525 nm 421nm increasingAgNO3 amount used spinningsolution. nmaverage particle size, independent usedAgNO3 amount, distributedevenly inside its constituent nanofibers. goodstability hybridnanofibrous membrane aqueousmedium 400rpm lessthan 2% massloss. When aqueousmedium raisedfrom 25 AgNPs/PNNmembrane abouthalf phasetransition temperature around 38 reachswelling deswellingequilibrium state within 15 aqueousmedium temperature jumping plungingbetween 25 resultsindicates AgNPs/PNNhybrid nanofibrous membrane possesses remarkable temperature-responsiveness highlyfast response rate. AgNPs/PNNhybrid nanofibrous membrane hold catalytic activity 4-nitrothiophenol(4-NTP) 4-aminothiophenol(4-ATP) AgNPscontent. catalyticactivity obviouslydependent reactiontemperature, which declines during temperature inducing phase transition membrane,showing addition,AgNPs/PNN hybrid nanofibrous membrane catalysthas well stability AgNPs/PNNhybrid nanofibrous membrane can free-standingSERS substrate itsSERS efficiency itsAgNPs content. When SERSsubstrate detectingtrace amount aqueoussolution, its detection limit lessthan 10 -12 wellreproducibility detectionresults. SERSactivity AgNPs/PNNmembrane notablytemperature-dependent, which temperaturewithin rangefrom 35 detectionsensitivity based SERSsubstrate can elevatingdetection temperature. Moreover, NaBH4can detected,which identifyingits mechanism, intermediateproduction rate万方数据 东华大学硕士学位论文 摘要 IV determining step wholereaction. Wang Liying (Chemistry) Supervised Prof.Liusheng Zha KEYWORDS: intelligent hybrid nanofibrous membrane, silver nanoparticle, temperature- responsiveness, catalytic activity, SERS, substrate, electrospining, situmonitoring reaction 万方数据 东华大学硕士学位论文 目录 目录