【作者】 张弛；

【导师】 范丽娟；

【作者基本信息】 苏州大学 ， 化学， 2021， 硕士

【摘要】 手指末端凹凸皮肤形成的摩擦脊具有唯一性和持久性,当手指与客体接触,便会在客体上形成指纹。由于终生不变、人各不同、触物留痕的特点,指纹成为了身份识别的重要依据,不仅可以用于信息的加密和解密,还在百余年的实践中逐渐成为了案件侦破中不可或缺的“物证之首”。目前,基于荧光材料的指纹显现方法得到了许多关注和研究。与非荧光的方法相比,基于荧光材料的指纹显现方法最显著的优势是降低了背景干扰。此外,目前的大多数方法仅对油脂指纹或血指纹中的一种有效,很少有方法能够显现两种指纹。基于以上背景,本论文提出一种指纹的“自适应性”显现策略,基于非笔直共轭骨架聚苯撑乙炔噻吩撑(PPETE),通过侧基的季铵化获得带正电的、离子密度不同的荧光共轭聚合物。通过分子设计赋予共轭聚合物“变色龙”的性质,即该共轭聚合物在一定条件下具有自适应性,在显现不同成分的指纹时能够自由切换与指纹的相互作用,从而实现油脂指纹和血指纹的自适应性显现。第一部分:通过Sonogashira偶联以及季铵化反应合成了每个重复单元含有一个阳离子侧基的荧光共轭聚合物PPETE-NMe3+,并通过相关的表征确认了其分子结构。光物理性质的表征表明季铵化前、后的聚合物在吸收和发射以及荧光量子产率上没有明显差异,均具有较好的发光性能。经优化,选定浓度0.1 mg/mL的PPETE-NMe3+的N,N-二甲基甲酰胺(DMF)溶液作为显现液,通过简单的滴涂并孵育的方法实现了对七种非渗透性客体上的油脂指纹和血指纹的自适应性显现;本显现体系能够显现老化30天的指纹;也具备一定的显现灵敏度。此外,初步的机理研究说明,季铵化改变了聚合物的溶解性,并且可能为聚合物与指纹成分之间带来更丰富的相互作用;此外,指纹中的脂肪酸、甘油酸酯、蛋白质、氨基酸与聚合物之间存在的弱相互作用(如疏水作用、静电作用或二者的协同作用)是实现自适应性显现的关键。第二部分:在第一部分的基础上,通过改变单体,合成了每个重复单元含有三个阳离子侧基的荧光共轭聚合物PPETE-3NMe3+,并通过相关表征确认了其成功合成。PPETE-3NMe3+在乙醇、甲醇、DMF、二甲亚砜(DMSO)和水中都有良好的溶解性。动态光散射、透射电子显微镜和Zeta电位测试结果表明PPETE-3NMe3+以纳米颗粒的形式稳定存在于水中。以水为溶剂的PPETE-3NMe3+显现液成功实现了多种客体上指纹的自适应性显现。此外,本体系能够显现老化180天之久的指纹;显现后的指纹也能够储存至少100天;本体系具有供体普适性,能够有效显现不同年龄和性别的志愿者的油脂指纹;本体系还具有较高的显现灵敏度和准确性。对显现机理的初步探究表明指纹与聚合物之间的作用是一种弱相互作用,聚合物通过这种弱相互作用与指纹中的脂肪酸、蛋白质和胆固醇结合,但是具体的作用类型仍待进一步探索。更多还原

【Abstract】 Fingerprints are friction ridge skin impressions of fingers.They are permanent and unique.When touching a substrate,fingerprints will be left.Because of these characteristics,fingerprints have become important in identification.Not only can they be used for encryption and decryption of information,but they have also become indispensable in case solving.At present,methods based on fluorescent materials have received soaring attention.Compared with non-fluorescent ones,the most significant advantage of fluorescent materials-based fingerprint development methods is the reduction of background interference,so that fingerprints on various substrates can be developed.Besides,most of the current methods are only effective for either sebaceous fingerprints or blood fingerprints,and few methods can develop both.This thesis proposes an adaptive strategy for fingerprint development.Cationic fluorescent conjugated polymers with non-straight conjugated backbone poly[p-(phenylene ethylene)-alt-(thienylene ethynylene)](PPETE)and different ion densities in each repeating unit could be obtained.This strategy endows the conjugated polymers with properties of a "chameleon",that is,the conjugated polymers are self-adaptive under certain conditions,namely they can freely switch the interaction with fingerprints when developing different fingerprints,so that both sebaceous and blood fingerprints may be effectively developed.The first part:A fluorescent conjugated polymer PPETE-NMe3+ with one cationic side group in each repeating unit was synthesized.Photophysical properties indicates that there was no significant difference in absorption,emission and fluorescence quantum yield between the polymers before and after quaternization,suggesting that both polymers had good photophysical properties.After optimization,DMF solution of PPETE-NMe3+with a concentration of 0.1 mg/mL was selected and realized the adaptive development of the sebaceous fingerprints and blood fingerprints on seven non-porous substrates.In addition,PPETE-NMe3+was able to develop fingerprints aged for 30 days.It was also found that PPETE-NMe3+ had high sensitivity in developing fingerprints.By studying the necessity of quaternization and the interactions that exist in the process of fingerprint development,the mechanism of fingerprint development was explored.The preliminary conclusion is that the weak interactions(such as hydrophobic interactions,electrostatic interactions or the synergy of the two)between fingerprint components(fatty acids,glycerides,proteins and amino acids)and PPETE-NMe3+ are the keys to realize this adaptive strategy.The second part:By changing one monomer,a fluorescent conjugated polymer PPETE3NMe3+ with three cationic side groups in each repeating unit was synthesized,and its successful synthesis was confirmed by related characterization.PPETE-3NMe3+had good solubility in ethanol,methanol,DMF,dimethyl sulfoxide(DMSO)and water.Dynamic light scattering and transmission electron microscopy results showed that PPETE-3NMe3+existed stably in water as nanoparticles.An aqueous solution of PPETE-3NMe3+was used to develop sebaceous and blood fingerprints.The system was effective when developing fingerprints aged for 180 days;Developed fingerprints could be stored for at least 100 days;Multi-donor test showed sebaceous fingerprints left by different volunteers could also be effectively developed.A preliminary mechanism exploration also confirmed weak interactions between fingerprints and PPETE-3NMe3+.更多还原