Photoluminescent Honeycomb Films Templated by Microwater Droplets

Abstract

The europium polyoxometalate anion, [EuW(10)O(36)](9-), can be transferred from an aqueous phase into a chloroform phase through encapsulation by dioctadecyldimethylammonium (DODMA(+)). The formed (DODMA)(9)[EuW(10)O(36)] complexes can self-assemble into ordered, uniform porous honeycomb films by using a simple solvent-evaporation method at the air/water interface without any extra moist airflow. TEM, SEM, and AFM observations show porous morphologies with pores having a diameter of about 2 microm and a wall depth of about 0.8 microm. The microlamellar structure and crystalline nanoaggregates of (DODMA)(9)[EuW(10)O(36)] complexes in films are characterized by XRD measurements and high-resolution TEM observations. During self-assembly into porous honeycomb films, it is speculated that the cooled microwater droplets that are induced by the quick evaporation of chloroform act as the templates for pores and that (DODMA)(9)[EuW(10)O(36)] complexes are deposited around pores. Because of the intrinsic fluorescence of [EuW(10)O(36)], the photoluminescent porous honeycomb films of (DODMA)(9)[EuW(10)O(36)] complexes can emit fluorescence when they are excited by UV light. It is expected that this will meet more requirements of new materials for fluorescence, separation membranes, microstructured electrode surfaces, containers, and reactors.

Breath Figure: A Nature-Inspired Preparation Method for Ordered Porous Films

“…Moreover, a heat treatment at 110°C provided C 9 H 19 COOH/Co particles with magnetic properties, and an external magnetic field was able to influence the formation of the C 9 H 19 COOH/Co-based BFA film. 355 In other reports, Wu 153,356 and Hao 357,358 demonstrated that a POM/ surfactant complex produced in chloroform could form regular BFA films by a dynamic BF process or at the air/water interface. Saito et al prepared BFA films using Al 2 O 3 NPs stabilized with a polymer containing catechol groups.…”

Advances in Fabrication Materials of Honeycomb Structure Films by the Breath-Figure Method

“…In addition, Wu et al . [40,113,114,115,116,117,118] have shown that surfactant-encapsulated polyoxometalate (POM) clusters are a new type of building block for fabrication of honeycomb structures. A series of hydrophobic surfactant-encapsulated clusters prepared from POM with different compositions, shapes, and sizes, are able to self-assemble into ordered honeycomb structures [113,117].…”

Assembly of Polyoxometalate-Based Composite Materials

“…Figure 1 shows the TEM images of an inhomogeneous microporous film (a), highly ordered honeycomb films (b,c), broken net structure (f), and HRTEM images of the highly ordered honeycombs (d, e). Also, Hao et al made photoluminescent uniform porous honeycomb films based on (DODMA) 9 [EuW 10 O 36 ] that were constructed at the air/water interface using microwater droplets as a template without any extra moist airflow [18]. The formation mechanism of the honeycomb-patterned films at the air/water interface was concluded that the condensed micrometer water droplets with hexagonal array by the quick evaporation of solvents were considered as templates for the formation of ordered microporous films [18,19].…”