Fabrication of Pore-Selective Metal-Nanoparticle-Functionalized Honeycomb Films via the Breath Figure Accompanied by In Situ Reduction

Abstract

Honeycomb films pore-filled with metal (Au, Ag, and Cu) nanoparticles were successfully prepared by combining the breath figure method and an in situ reduction reaction. First, a polyhedral oligomeric silsesquioxane (POSS)-based star-shaped polymer solution containing metal salt was cast under humid conditions for the formation of honeycomb films pore-filled with metal salt through the breath figure method. The morphology of the honeycomb films was mainly affected by the polymer molecular structure and the metal salt. Interestingly, the promoting effect of the metal salt in the breath figure process was also observed. Then, honeycomb films pore-filled with metal nanoparticles were obtained by in situ reduction of the honeycomb films pore-filled with metal salt using NaBH4. Notably, the metal nanoparticles can be selectively functionalized in the pores or on the surface of the honeycomb films by controlling the concentration of the NaBH4. Metal-nanoparticle-functionalized honeycomb films can prospectively be used in catalysis, flexible electrodes, surface-enhanced Raman spectroscopy (SERS), and wettability patterned surfaces.

Development of an UV−Resistant Multilayer Film with Enhanced Compatibility between Carboxymethyl Cellulose and Polylactic Acid via Incorporation of Tannin and Ferric Chloride

“…The addition of Fe 3+ significantly reduced the porosity and pore area of the film surface, which was attributed to the fact that the chelation between Fe 3+ , tannin, and CMC reduced the distance between PLA molecules. Furthermore, there was about 2% FeCl 3 contained in both samples, and the solvation of FeCl 3 was thought to increase the surface energy of the droplets, consequently reducing their volume [ 30 ]. Compared to the CMC/TA−PLA/Fe ( Figure 1 D1) film, the pores on the surface of the CMC−PLA/Fe ( Figure 1 C1) film were smaller, with a porosity of only 3.12%, which was attributed to the limited cross−linking rate of CMC with Fe 3+ compared to the rapid cross−linking of tannins with Fe 3+ .…”

Novel Capturer-Catalyst Microreactor System with a Polypyrrole/Metal Nanoparticle Composite Incorporated in the Porous Honeycomb-Patterned Film

“…The pyrrole contained in the humid conditions increases the air/polymer solution interfacial force due to the pyrrole being soluble in water in spite of organic material. Similarly, the addition of metal salt in the polymer solution increases the air/polymer solution interfacial force by increasing the hydrophilicity of the polymer solution. − Therefore, the pore size of PCL-Cu film is greatly decreased. However, the PPy polymer coating formed by one-step polymerization during the BF process could inhibit the packing of the water droplet by evaporation.…”

Modified Breath Figure Methods for the Pore-Selective Functionalization of Honeycomb-Patterned Porous Polymer Films

“…Recent developments in the BF method have led to the advancement of the technique by self-assembly followed by additional treatment due to the possibility of combining organic and inorganic compounds. Therefore, the creation of new materials with tailored properties has attracted much attention and considerable literature has grown up around the fabrication of such materials via the modified BF method, summarized in Table 1 [ 70 , 97 , 98 ]. This method usually requires two steps for the pore-selective functionalization of the HCP films.…”

“…This method is generally popular for the synthesis of metal NPs, where a metal precursor is added in the polymer solution followed by its chemical reduction using a reducing agent such as sodium borohydride, sodium citrate, citric acid, ascorbic acid, and hydrazine [ 99 ]. For instance, Li et al reported the addition of metal salts, such as HAuCl 4 , AgNO 3 , and CuCl 2 , in the polymer solution to fabricate metal-salt-filled HCP films [ 97 ]. Later, aqueous NaBH 4 was poured onto the prepared films to reduce the metal salts inside the pores to metal NPs filled pores shown in Figure 8 .…”