【作者】 龚晓；

【导师】 高长有；

【作者基本信息】 浙江大学 ， 材料学， 2009， 博士

【摘要】 基于层层自组装的聚电解质多层膜因其结构、组成和性质等的易可控性而得到了飞速发展。世界知名的CIBA公司于2002年推出了第一款以层层自组装超薄膜为表面涂层的产品。聚电解质多层膜在基础研究和应用开发方面都取得了丰硕的成果。通过改变聚电解质多层膜的结构或引入功能性组份(如纳米粒子，荧光量子点等)，还可获得具有各种功能的层层组装聚电解质多层膜。本课题组发现了聚电解质多层膜具有可压缩的现象，为多层膜的物理图案的构建提供了一种新的方法。多层膜压缩后，也引起了一系列的性质变化。在此基础上，本文着眼于强弱共聚的聚电解质即聚苯乙烯共聚马来酸(PSSMA)为负电解质，通过改变组装时盐浓度和种类、pH值来调控多层膜的组装和压缩，另外，把压缩和纳米粒子的原位合成结合，赋予多层膜新的功能。首先，研究了盐对PSSMA／聚二烯丙基二甲基铵盐酸盐(PDADMAC)多层膜的影响，发现随着组装时NaCl浓度的增加，多层膜的压缩率是逐渐增加的；而随着NaBr浓度的增加，多层膜的压缩率却基本保持不变。通过改变盐的浓度和种类，可以方便地可逆调控多层膜的性质和压缩程度。其次，研究了pH值对多层膜的组装和性质以及压缩对多层膜内原位合成银纳米粒子的影响。系统研究了聚电解质溶液pH值对多层膜的厚度、表面形貌及压缩性质的影响。研究发现，在pH 4条件下组装的多层膜指数化程度最大，膜最厚。随着pH值的增加，其指数化程度逐渐降低；在pH为8时，其指数化程度为最低。pH 2和pH 10条件下组装的多层膜则呈线性增长。利用原位合成技术在多层膜内制备了纳米银粒子。综合紫外和XRD的测试结果可知，在pH 2，pH 4和pH 5的条件下组装的多层膜，未压缩膜内生成的纳米银粒子较压缩后膜内生成的纳米银粒子多。而在pH 6的条件下，未压缩膜和压缩膜中纳米银粒子的数量并没有明显的差异，数量都非常少。另外，发现了形成纳米粒子的过程对多层膜内部分子的链重排起到了关键作用。再次，研究了金属铜离子对多层膜的性质和压缩的影响。发现铜离子浓度影响多层膜的增长方式。当多层膜中存在铜离子时，多层膜很难被压缩；一旦铜离子被除去后，多层膜的压缩程度则大幅度提高。最后，系统地研究了不同干燥时间对多层膜压缩形成图案的影响，发现随着多层膜干燥时间的增加，经压缩后依次可以得到双条带、脊状和薄条带图案，提出了压缩模型和机理。另外，也研究了多层膜图案化压缩后的稳定性动力学问题，以及图案稳定性的控制问题。利用多层膜在含水量较多时压缩具有侧向流动这一原理，我们简化了压缩手段，并且可以很方便地进行纳米粒子三多层膜表面的定向排列。更多还原

【Abstract】 Over the past decades, the polyelectrolyte multilayers assembled with thelayer-by-Layer (LbL) technique have been well developed because of theircontrollable compositions, structures and properties. The polyelectrolyte multilayershave achieved great success in both of fundamental researches and practicalapplications. CIBA-Vision has announced the first commercially available productthat is equipped with a multilayer coating in 2002. The functional polyelectrolytemultilayers can also be fabricated by changing their structures or introducingfunctional materials such as nanoparticles or luminescent quantum dots. Recently, ourgroup has reported the irreversible compression of polyelectrolyte multilayers bypressing a poly(dimethylsiloxane) (PDMS) stamp against the films. It furtheraugments the technique for fabricating physical patterns of the polyelectrolytemultilayers. It also brings new properties after the multilayers are compressed.In this work, the focus is on the polyelectrolyte poly(4-styrenesulfonicacid-co-maleic acid) sodium salt (PSSMA) containing both strongly charged andweakly charged blocks. The assembling behaviour, properties and compression ratiosof the PSSMA/poly(diallyldimethylammonium chloride) (PDADMAC) multilayerscan be easily controlled by adjusting salt concentrations and salt type or theassembling pH value. Combining compression with in situ synthesis nanoparticles,the multilayers are endowed with new functions as well.Firstly, influence of salt on assembly and compression of PSSMA/PDADMACmultilayers was studied. Results reveal that the compression ratio increased alongwith the increase of NaCl concentration, whereas kept constant when NaBr was used.It shows that the properties and compression ratios of the multilayers were reversiblymediated by the salts.Secondly, controlling the properties and compression of the multilayers by pHand effect of compression on in situ synthesis of Ag nanoparticles in the multilayerswere carried out. Influence of pH on the thickness, morphology and compression of the multilayers was detailedly studied. The multilayers assembled at pH 4 showed thelargest exponential growth, and it was thickest. With the increase of pH, the degree ofexponential growth of the multilayers decreased. The multilayers assembled at pH 2and pH 10 showed the linear growth. Ag nanoparticles were obtained by in situsynthesis in the multilayers. When the multilayers were assembled at pH 2, 4, and 5,the numbers of Ag nanoparticles in the compressed multilayers were much fewer thanin the uncompressed multilayers, while the multilayers were assembled at pH 6, thenumbers of Ag nanoparticles in the compressed multilayers and in the uncompressedmultilayers were both very few. Results reveal that the process of in situ synthesisnanoparticles plays a key role in readjustment of the polyelectrolyte chains.Then, the properties and compression of the multilayers were tuned by copperions. The copper ions concentrations affected the multialers growth. When themultilaylers contained the copper ions, their compression ratios were small; however,when the copper ions were removed from the multilayers, the compression ratioscould be largely improved.Finally, we found that the pattern formation of the multilayers was dependent onthe drying time of the multilayers prior to compression. Along with the prolongationof drying of the multilayers, compression of the multilayers by a stamp with linearpatterns obtained double strips, high ridges and linear patterns on the multilayers,respectively. Based on these observations, a theoretical model was suggested. Thestability kinetics of the pattern for the compressed multilayers and the stabilitycontrolling of the pattern were studied. Based on the mechanism of the lateral flow ofthe multilayers, the compression process was simplified, and we successfully arrayedthe nanoparticles on the multilayers.更多还原