Poly (ionic liquid)-Based Breath Figure Films: A New Kind of Honeycomb Porous Films with Great Extendable Capability

Abstract

In this work, we reported a new method for the convenient fabrication of various functional porous films, which cannot be directly generated using breath figures (BFs). A series of polystyrene-b-poly (ionic liquid) (PS-b-PIL) block copolymers were employed for BFs process for the first time. It was found that PS-b-PIL could form well-defined BFs porous structure. Remarkably, the described PSb-PIL copolymers are prone to form hierarchical structure, and the formed pore structure is strongly dependent on the used experimental parameters. Importantly, we found that the anion exchange could provide as an effective means, by which the porous films could be further and facilely converted into other functional films. As a demonstration, in our case, porous films with different surface (hydrophilic and hydrophobic) property, porous polydopamine films decorated with Au nanoparticles or glutathione and porous SiO 2 films were prepared by using different counteranions as well as further conversion. Due to the unlimited combination of cation and anion in ionic liquid moiety, all the results indicate that the BFs films generated by using PS-PIL could serve as a platform to access various functional porous films by a simple counteranion exchange, showing a great extendable capability. François et al. 1 which is a rapid, low-cost and versatile approach for efficiently producing regular porous honeycomb films. In the past two decades, honeycomb structured films have drawn considerable attention owing to their huge potential applications in a wide variety of fields, including as template 2 , separation 3 and sensor 4 . Up to now, a widely recognized mechanism of BFs is described below. Firstly, the solution cooled and water vapor condensed, producing small and disordered water drops on the surface of the solution. Secondly, the water drops grew and self-assembled, forming a closely packed and regular array on the surface of the solution. Finally, the solvent and water drops evaporated successively, fabricating regular porous honeycomb film [5][6][7] . By using BFs approach, a large number of regular porous honeycomb films with various structures and morphologies have been fabricated [8][9][10][11] . Breath figures (BFs) which is first reported in 1994 byThe materials suitable for the BFs process, however, are limited to soluble polymers and a small group of other materials 11 . A lot of functional materials cannot be directly utilized in the BF process. Thus, developing new strategy to access extended porous materials by exploiting the advantages of the BFs process is highly desirable. Few studies have been reported to address the relevant problems. For example, Li and co-workers use ferrocene and zinc acetylacetonate as precursors, Fe 2 O 3 and ZnO inorganic porous honeycomb structures can be fabricated by pyrolysing corresponding PS-b-PAA/precursor composites breath figures arrays. These inorganic honeycomb patterns are used as either nuclear site or catalyst, which further direct the formation of CNTs patterns by chemical va...

Water Droplet Self-Assembly to Au Nanoporous Films with Special Light Trapping and Surface Electromagnetic Field Enhancement

“…These results are near to the maximum EF estimated by theoretical studies, 5 × 10 8 for Au nanosphere arrays . Thus, Au breath figure substrates are very promising since substrates previously reported have EF values in the range of 10 3 –10 5 . − , The present results strongly encourage the employment of metal nano-breath figure substrates for solar cells, photocatalysis, biosensors, and other plasmonic devices …”

“…[70][71][72]74 The present results strongly encourage the employment of metal nano-breath figure substrates for solar cells, photocatalysis, biosensors, and other plasmonic devices. 75 ■ ASSOCIATED CONTENT * S Supporting Information…”

Preparation of porous silicon rubber membranes by breath figure method

“…In addition, according to the pore‐forming principle of the breath figure method, the large temperature drop caused by solvent evaporation is the key to water vapor condensation and water droplet growth . Boiling point is an important characterization parameter for solvent volatility.…”

“…It is widely used in petrochemical, biomedical, mechanical, environmental, aerospace, electrochemical, and so on . Porous materials have excellent properties and have become important functional structural materials and are used as catalysts, super capacitors, adsorbents, and filtration devices …”

One‐Step Template‐Free Laser Patterning of Metal Microhoneycomb Structures

“…[11,12] In addition, the pore size can be controlled by adjusting the type of polymer [13,14] or surrounding environment. [15,16] This dynamic template method has been utilized in various applications [17][18][19] due to the simplicity of the process under ambient conditions. However, using a polymer necessitates additional deposition processes for forming metal structures.…”