Marangoni Force Assisted Spreading and Printing of Nanometer‐Thick Polymer Films for Ubiquitous Optoelectronic Devices

Abstract

Printable organic electronics are attractive owing to its high throughput and easy fabrication. Traditional coating methods (such as inkjet printing) are liquid‐solid contact‐based that deposit liquid solutions onto solid surfaces. Film quality is limited by surface energy of target surfaces and surface tension of the solvents. Furthermore, these printing methods are challenging to directly fabricate films on non‐flat or curved surfaces owing to the fluidity of liquid solution drops. In this work, a water transfer printing method that is solid‐solid contact‐based and assisted by Van der Waals force is reported. Nanometer‐thick films can be deposited on various surfaces: both high‐ and low‐surface energy, both flat and non‐flat surfaces. Water plays two roles: 1) as the transfer medium substrate and providing weak adhesion force between water and the transferred film; 2) high surface tension of water providing room to create surface tension gradient and producing Marangoni force to unfold the crumpled nanometer‐thick films. Electronic and optoelectronics on wrinkled skin and curved surfaces are demonstrated with this water transfer printing method.

Effects of cation size on thermoelectricity of PEDOT:PSS/ionic liquid hybrid films for wearable thermoelectric generator application

“…Inspired by recent work, Xie et al proposed the strategy of creating Marangoni force to help unfold the crumpled thick polymer films and perform transfer printing on various surfaces. 77 In the transfer printing method, the drop-cast PEDOT:PSS/MMIM BF 4 thick films were suspended in deionized water, and the Marangoni force produced from the surface tension gradient by adding alcohol into the water pulled the films on the water surface. Thus, the free-standing PEDOT:PSS/MMIM BF 4 films can transfer onto various surfaces such as the non-flat back of the hand (Fig.…”

Solution‐Processed Semiconductor Materials as Cathode Interlayers for Organic Solar Cells

“…In large-area processing, the variation of film thickness may reach ±10 nm, which severely degrades the performance of dipole-based CILs due to the non-constant film thickness. [54] This excludes the application of most dipole-based CILs in the large-area fabrication.…”

Formation of Balloon with Porous Structures in NaCl Vapor Assisted by Amphiphilic Polymer for Stent Delivery System

“…Simultaneously, they actively move within the solution owing to the Marangoni flow generated by solvent evaporation. [22,34,35] Furthermore, as the viscosity of the solution increases continuously until solidification, the floatability of the droplets decreases, leading to the formation of a sponge-like structure (c). On the other hand, if a hydrophilic functional group reacts at the high position of the droplet, breath figure patterns exist only on the interface (c′).…”