Characterization of zirconium phosphate polycation thin films grown by sequential adsorption reactions
Characterization of zirconium phosphate polycation thin films grown by sequential adsorption reactions
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DOI：
10.1021/cm970027q
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发表时间：
1997-06-01
影响因子：
8.6
通讯作者：
Decher, G
中科院分区：
文献类型：
--
作者：
Kim, HN;Keller, SW;Decher, G
采用透射电子显微镜（TEM）、椭偏仪、紫外可见吸收光谱、红外光谱（FT-IR）、XPS和x射线衍射对阴离子磷酸锆（alpha-ZrP）片和阳离子（聚丙烯胺盐酸盐（PAH）、细胞色素c）组成的单层和多层薄膜进行了表征。滴定和粉末x射线衍射实验证实，当加入足够多的四（正丁基铵）氢氧化物(TBA(+)OH(-))，使其在插层化合物Zr(HPO4)(2-x)(TBA(+)PO(4)(-))(x)中超过单层的TBA（+）离子(x)时，α - zrp开始脱落。nH (2) O。在TEM显微照片中，许多薄片的相同对比度表明悬浮液是单层状的。将阳离子底物交替浸入含有α - zrp的悬浮液和水性多环芳烃中，得到类似于相应的体插层化合物的多层膜。多层膜的x射线光电子能谱表明，相对于α - zrp，多层膜是富zr的，与剥离反应过程中的腐蚀相一致。通过椭偏仪和x射线衍射测量，α - zrp /PAH层对厚度分别为13/14.7埃。一个13层的对膜在堆叠方向上足够有序，在衍射图中产生布拉格峰。从衍射图低角度部分的Kiessig条纹测量的双层厚度和总膜厚度之间的一致性证实，在每个吸附步骤中只沉积了一个致密的α - zrp或多环芳烃单层。
Monolayer and multilayer thin films consisting of anionic alpha-zirconium phosphate (alpha-ZrP) sheets and polycations (poly(allylamine hydrochloride) (PAH), cytochrome c) were characterized by transmission electron microscopy (TEM), ellipsometry, UV-visible absorbance spectroscopy, reflectance FT-IR, XPS, and X-ray diffraction. Titration and powder X-ray diffraction experiments confirm that exfoliation of alpha-ZrP begins to occur when enough tetra-(n-butylammonium) hydroxide (TBA(+)OH(-)) has been added to exceed single-layer packing of TBA(+) ions (x approximate to 0.50) in the intercalation compound Zr(HPO4)(2-x)(TBA(+)PO(4)(-))(x) . nH(2)O. The identical contrast of many sheets in TEM micrographs suggests that the suspension is unilamellar. Alternately dipping cationic substrates into alpha-ZrP-containing suspensions and aqueous PAH gives a multilayer film that resembles the corresponding bulk intercalation compound. X-ray photoelectron spectra of multilayer films show that they are Zr-rich, relative to alpha-ZrP, consistent with some corrosion during the exfoliation reaction. The alpha-ZrP/PAH layer pair thickness is 13/14.7 Angstrom, as measured by ellipsometry/X-ray diffraction, respectively. A 13-layer pair film is sufficiently well-ordered in the stacking direction to give a Bragg peak in the diffraction pattern. The agreement between the bilayer thickness and the total film thickness, measured from Kiessig fringes in the low-angle part of the diffraction pattern, confirms that only a single dense alpha-ZrP or PAH monolayer is deposited in each adsorption step.