ASSEMBLY, STRUCTURAL CHARACTERIZATION, AND THERMAL-BEHAVIOR OF LAYER-BY-LAYER DEPOSITED ULTRATHIN FILMS OF POLY(VINYL SULFATE) AND POLY(ALLYLAMINE)
ASSEMBLY, STRUCTURAL CHARACTERIZATION, AND THERMAL-BEHAVIOR OF LAYER-BY-LAYER DEPOSITED ULTRATHIN FILMS OF POLY(VINYL SULFATE) AND POLY(ALLYLAMINE)
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DOI：
10.1021/la00026a020
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发表时间：
1993-02-01
期刊：
影响因子：
3.9
通讯作者：
MOHWALD, H
中科院分区：
文献类型：
--
作者：
LVOV, Y;DECHER, G;MOHWALD, H
我们最近介绍了一种在固体载体上制造均匀超薄膜的新方法，该方法基于相反电荷之间的静电吸引。阴离子和阳离子聚电解质从其水溶液中连续交替吸附导致多层组件的形成。利用小角x射线散射（SAXS）可以很容易地监测到多层膜的形成，并观察到膜厚度随吸附层数的增加呈线性增加。本文主要研究了聚硫酸乙烯基（PVS）和聚烯丙胺（PAH），重点讨论了PVS的吸附条件对膜的生长和性能的影响。发现薄膜的稳定生长取决于PVS沉积的两个先决条件：吸附时间至少为15 min，最大添加氯化钠浓度为0.2 mol/L。在稳定生长的状态下，多层膜能够将底层玻璃基板的表面粗糙度从18a平滑到4.5 A。在PVS溶液中加入少量电解质，可使单层对的厚度从13 A （0.0 mol NaCl/L）增加到34埃（0.9 mol NaCl/L）。这种行为类似于众所周知的溶液中聚电解质的“棒到线圈”转变，并且由于聚合物链上的静电电荷的筛选。这种薄膜在至少160摄氏度的温度下是稳定的，但在60摄氏度以上似乎会失去被困住的水分。
We have recently introduced a new method of creating homogeneous ultrathin films on solid supports, which is based on the electrostatic attraction between opposite charges. Consecutively alternating adsorption of anionic and cationic polyelectrolytes from their aqueous solution leads to the formation of multilayer assemblies. The multilayer buildup is easily monitored by small angle X-ray scattering (SAXS) and a linear increase of the film thickness with the number of adsorbed layers is observed. In the present study we concentrate on the polyelectrolytes poly(vinyl sulfate) (PVS) and poly(allylamine) (PAH), discussing especially the influence of the adsorption conditions of PVS on the growth and the properties of the resulting films. A stable film growth was found to depend on two prerequisites for the PVS deposition: an adsorption time of at least 15 min and a maximum concentration of added sodium chloride of 0.2 mol/L. In the regime of stable growth the multilayer film is able to smooth the surface roughness of the underlying glass substrate from 18 A to a value of 4.5 A. The addition of small amounts of electrolyte to the PVS solution leads to an increase of the thickness of one layer pair from 13 A (at 0.0 mol of NaCl/L) to 34 angstrom (at 0.9 mol of NaCl/L). This behavior is similar to the well-known ''rod-to-coil'' transition of polyelectrolytes in solution and due to screening of electrostatic charges on the polymer chain. The films are stable up to temperatures of at least 160-degrees-C but seem to lose trapped water above 60-degrees-C.