A Facile One‐Step Approach for Constructing Multidimensional Ordered Nanowire Micropatterns via Fibrous Elastocapillary Coalescence

Abstract

aligning NWs into micropatterns in order to achieve their advantages of integrated physicochemical properties and adequate device performance. [8] In this regard, various solution-coating techniques have been vigorously developed for their advantages in mild experimental conditions and large-scale production. So far, three categories of solution processes for aligning NWs have been reported based on the driving force: i) Anisotropic contraction of the solution film by the external forces, such as the technique of Langmuir-Blodgett; [9] ii) The shearing force technique where the NWs were aligned under the external shearing forces, including blown bubble film, [10] microfluidic approaches, [11] contact printing, [12] and solution shearing technique [13] ; and iii) Aligning NWs under applied external field, for example, the electric field of the dielectrophoresis approach. [14] However, these techniques suffer from limitations of either complicated equipment, sophisticated pretreated samples, difficulty in accurate controlling of the deposition region of the NWs, and the aggregation of NWs as well as the reorientation of the NWs in the postprocess. [15] Very recently, our group developed a facile directional liquid transfer approach guided by the Chinese brush to realize highly aligned Ag NWs through finely controlling the receding of the tri-phase contact line, [16] which is, however, not feasible for constructing multidimensional ordered micropatterns. So far, developing a facile and general approach to realize multidimensional, highly aligned micropatterned NWs has remained a challenge.In general, the essence of aligning NWs by solution coating is introducing directional force to compel NW ordering during the formation of NW film. As has been reported, carbon nanotube arrays (ACNTs) can be wetted by water gradually due to their surface texture and inherent hydrophilic nature. [17] As a result of water spreading and dewetting, fibrous coalescence of ACNTs occurs under strong capillary forces and Van der Waals interactions, by which ACNTs aggregated and bundled into micropatterns. [18] To be noticed, the anisotropic shrinking of the liquid film on the top of ACNTs happens in this process without any external energy input, which is an advantage for aligning NWs. Nanowire (NW) based micropatterns have attracted research interests for their applications in electric microdevices. Particularly, aligning NWsrepresents an important process due to the as-generated integrated physicochemical advantages. Here, a facile and general strategy is developed to align NWs using fibrous elastocapillary coalescence of carbon nanotube arrays (ACNTs), which enables constructing multidimensional ordered NW micropatterns in one step without any external energy input. It is proposed that the liquid film of NW solution is capable of shrinking unidirectionally on the top of ACNTs, driven by the dewetting-induced elastocapillary coalescence of the ACNTs. Consequently, the randomly distributed NWs individually rotate and move into dense alig...

Ice‐Templated, Large‐Area Silver Nanowire Pattern for Flexible Transparent Electrode

“…Flexible electrodes with excellent transmittance and low sheet resistance are highly demanded for the next‐generation electronic and optoelectronic devices [ 1–5 ] such as organic solar cells, [ 6–7 ] touch‐screen displays, [ 8–9 ] organic light‐emitting diodes, [ 10 ] and so on. Current flexible transparent electrodes are usually achieved by coating a flexible and transparent polymer substrate with a conductive layer composed of carbon materials (e.g., graphene, carbon nanotube), [ 11–15 ] metal nanowires (e.g., silver and gold nanowires), [ 16–20 ] and/or conductive polymers (e.g., PEDOT:PSS). [ 21 ] Among these conductive materials, silver nanowire (AgNW) has received tremendous attention in making flexible transparent electrodes for its excellent conductivity and mechanical flexibility.…”

Direct Writing Micropatterns with a Resolution up to 1 µm

“…3 mm using a tapered steel needle; casting the polydimethylsiloxane (PDMS) solution on the punched PE plate, followed by the heating treatment at 80 °C for 15 min; and then the unit of tri-CFs was prepared by peeling the cured PDMS CFs off from the PE sheet. The fibers in both units are arranged parallel in a side-by-side pattern, which were bent and re-shaped into bundles due to the fibrous capillary coalescence [29][30][31] after wetted (Figure 1a, and Figure S1c the fibers, [32,33] the ink is therefore stored steadily within the wet re-shaped CF arrays, forming a liquid reservoir. The fibers in both units are arranged parallel in a side-by-side pattern, which were bent and re-shaped into bundles due to the fibrous capillary coalescence [29][30][31] after wetted (Figure 1a, and Figure S1c the fibers, [32,33] the ink is therefore stored steadily within the wet re-shaped CF arrays, forming a liquid reservoir.…”

Multidimensional Aligned Nanowires Array: Toward Bendable and Stretchable Strain Sensors

“…Preparation of Multidimensional Aligned Nanowires Array: AgNWs were used dispersed in isopropyl alcohol with a concentration of 0.5 mg mL −1 , which enables AgNWs to cover all areas of the vertically aligned carbon nanotube array [30]. The ACNTs with the area of 1 × 1 cm 2 and the height of 150 µm were prepared by using chemical vapor deposition process, which involves the decomposition of xylene and ferrocene.…”

“…The essence of 1D nanomaterials arrangement is to introduce directional force during the film formation process, forcing 1D nanomaterials to arrange orderly. Recently, we developed multidimensional aligned NW array using fibrous elastocapillary coalescence of ACNTs that can align various NWs including Ag, ZnO, and Al 2 O 3 [30]. The anisotropic shrinking of the liquid film on the top of ACNTs happens in this process requiring no external forces, which is an advantage for aligning NWs.…”