Surfactant-Encapsulated Polyoxoanion:  Structural Characterization of Its Langmuir Films and Langmuir−Blodgett Films

Abstract

We synthesized a surfactant-encapsulated polyoxoanion, (DODA)16As4W30Cu4O112‚114H2O (denoted SEC-1), which possesses a hydrophobic dimethyl dioctadecylammonium (DODA) shell and an encapsulated hydrophilic polyoxoanion core in organic phases. The novel organic/inorganic composite can form stable Langmuir monolayers, but it is significantly distorted when spread onto an air/water interface although the general core-shell structure seems to remain. Langmuir-Blodgett (LB) films of SEC-1 are readily prepared by transferring the monolayers onto substrates with a transfer ratio near 1. It has been proposed that there exist well-orientated alkyl chains and highly defined layer structure in LB films. Fourier transformation infrared spectroscopy at different temperatures indicates that two obvious phase transitions appear near 34 and 47 °C for multilayer LB films of SEC-1. The polyoxoanion can be organized to some extent within LB films with its long axis parallel to the substrate by comparing the IR transmission spectrum with the reflection-absorption spectrum. The one-monolayer LB film of SEC-1 possesses a homogeneous and flat surface morphology, and a water contact angle of 104 ( 3°for odd-layer LB films shows a highly hydrophobic surface.

Organized Nanostructured Complexes of Polyoxometalates and Surfactants that Exhibit Photoluminescence and Electrochromism

“…Following this, the structure of Langmuir and LB films of SECs, and various functional assemblies based on SECs were investigated. [27][28][29][30][31][32][33][34][35][36] POM-containing multilayers with photocatalytic, A variety of functional nanostructured organic/inorganic hybrid materials from the europium-exchanged derivative of a Preyssler-type polyoxometalate (POM), [EuP 5 W 30 O 110 ] 12À , and functional organic surfactants were prepared by the ionic self-assembly (ISA) route. The effect of organic surfactants on the structure, photoluminescent, electrochemical and electrochromic properties of the POM anions was investigated in detail.…”

A novel polymerizable pigment based on surfactant-encapsulated polyoxometalates and their application in polymer coloration

“…2), as are other SECs. This is the result from the strong electrostatic interaction between surfactants and POMs, as suggested in the literature [8,11]. That is, the surfactants are immobilized on the surface of POMs, and to some extent, their mobility is confined, especially for their head regions.…”

“…The SECs were prepared following a procedure reported previously [11]. For the DMDA/Co1 complex, Co1 was dissolved in aqueous solution, and then a chloroform solution of DMDA was added with stirring.…”

Incorporation of Polyoxometalates Into Polystyrene Latex by Supramolecular Encapsulation and Miniemulsion Polymerization

“…[10] For example, Eu1 was dissolved in aqueous solution, and then a chloroform solution of DMDA was added with stirring. The initial molar ratio of DMDA to Eu1 was controlled at 8.5:1.…”

“…This result implies the immobilization of DMDA resulting from the strong electrostatic interaction between DMDA head and POMs, and some similar instances have also been reported in literature. [10] Of significance is the intrinsic properties of POMs such as the characteristic …”