Template‐ and Vacuum‐Ultraviolet‐ Assisted Fabrication of a Ag‐Nanoparticle Array on Flexible and Rigid Substrates

Abstract

The fabrication of well-ordered metal-nanoparticle (NP) arrays on either rigid or flexible substrates is of considerable interest in modern science and technology for applications as diverse as electronics, photonics, informatics, sensors, and catalysis.[1] For example, nanofabrication on optically transparent flexible substrates is spawning novel and unique applications, including plastic electronics and organic light-emitting displays.[2] A template-assisted nanofabrication strategy based on self-assembled nanostructures is one promising method for macroscopically manipulating nanopatterned surfaces for practical applications. [1][2][3][4][5][6][7][8][9] Among the potential self-assembled templates, phase-segregated block copolymers have drawn much attention because they can give rise to tunable periodic nanostructures with various geometries. [3][4][5][6][7][8][9][10] Many approaches, including physical vapor deposition, [11,12] chemical vapor deposition, [13][14][15] electroless deposition, [16,17] galvanic displacement, [18,19] electrochemical plating, [20,21] sol-gel chemistry, [22] chemical reduction, [23] and pyrolysis, [24] have been widely explored as options for arranging metal NPs onto robust substrates by using a block copolymer template. For example, very recently our group has demonstrated that Au NPs can be assembled via a site-specific recognition between hydrophilic/ hydrophobic NPs and the nanodomains of phase-segregated, amphiphilic, diblock copolymer films. [25] In contrast, a novel hybrid nanofabrication process, block copolymer lithography, [26][27][28][29][30][31][32] has recently been extensively investigated because it successfully combines advantages of both the top-down (lithography) and bottom-up (block copolymer template) techniques, where high-energy irradiation, such as laser, [26] plasma, [27][28][29] electron beam, [30] or ion beam, [31,32] has been utilized to both generate periodic arrays of nano-objects and remove the copolymer template in a single step. [3][4][5][6][7][8][9] Unfortunately, less attention has been paid to the site-selective metallization of long-range-ordered nanostructures on optically transparent polymer substrates, potentially leading to flexible electronic and photonic devices beyond conventional Si-based technology.[1] A further challenge is to develop a versatile procedure for efficient nanostructure fabrication on both soft and hard substrates.[2] Herein, we demonstrate the simple but widely applicable vacuum ultraviolet (VUV)-assisted nanofabrication of a hexagonally arranged, high-density Ag-NP array with a tunable interparticle distance on either a rigid or flexible substrate over a large area. The key to the nanofabrication process described here is that the VUV irradiation drives both the photoreduction of the selectively infiltrated Ag + to metallic Ag NPs and the etching of the template of the copolymer film in one step. It is well known that Ag + can be photochemically reduced in the presence of an appropriate electron donor, [33] and this appro...

Self-assembled block copolymers: Bulk to thin film

“…Even though PS-b-PI exhibits disordered state in the entire temperature range, the addition of the liquid crystalline group increased the T ODT significantly. 262 Iyoda and coworkers [263][264][265][266][267] prepared an interesting liquid crystalline block copolymer, PEO-b-PMA(Az) where liquid crystal moiety of azobenene (Az) is attached to PMA block. Here, two different domains are generated: microdomains due to the chain segregation between PEO and PMA(Az) blocks, and nanodomains arising from the liquid crystal smetic phase of Az.…”

Phase-selective staining of metal salt for scanning electron microscopy imaging of block copolymer film

“…However, TEM is very sensitive to sample preparation, where the specimen should be sliced thin enough to guarantee electron beam transmission for imaging. On the other hand, atomic force microscopy (AFM) has been intensively applied to evaluate BCP films since AFM mapping can be performed either in air or in vacuum [8][9][10]. However, AFM scanning speed is relatively slow, and the spatial resolution is poorer than that of TEM.…”

Efficient adsorptive desulfurization by task‐specific porous organic polymers

“…The peaks at about 368.6 and 374.7 eV (Figure S9), corresponding to Ag 3d 5/2 and Ag 3d 3/2 , suggest that the incorporated Ag(I) sites maintain very well. 48 However, the Ag(I) content slightly decreased from 17 to 16% after regeneration (Table 1 and Table S3), which may account for the reduction of uptake capacity.…”