A spring network simulation in three dimensions for designing optimal crack pattern template to fabricate transparent conducting electrodes

Abstract

Desiccation cracks in colloids are of the order of µm width or less. Therefore, such connected crack networks in a desiccating colloidal film can provide a very fine template for the fabrication of transparent conducting surfaces by vapour deposition of a metal onto the crack network (Rao et al 2014 Adv. Mater. Interfaces 1 140009). The colloidal layer is removed leaving a connected metallic network invisible to the eye. So the surface becomes conducting, while retaining its transparency. The challenge lies in maximizing electrical conductivity while retaining the transparency as far as possible. An optimal combination of the system parameters, which affect the morphology of the crack network is necessary to meet this challenge. In this work, we simulate crack pattern in desiccating colloidal films in three dimensions using a spring network model. We look for the optimal combination of system parameters, such as film thickness, material stiffness and polydispersity, which can produce the best template for producing a conducting network on transparent surfaces.

Time Evolution and Spatial Hierarchy of Crack Patterns

“…It is found that the experimentally obtained crack pattern with time goes well with the predicted time evolution of cracks. Furthermore, the simulated patterns of cracks using spring fusion-based modeling 26 also possess the widening of cracks, strengthening the proposed assumption. In the spring fusion model, the film is represented as a cuboidal lattice with nodes representing the particles and Hookean springs connecting the nearest neighbors representing the interaction.…”

Cracking of Colloidal Films to Generate Rectangular Fragments

“…In particular, we demonstrated cracking at tapered edges between pyramids to prepare microscale pyramidal particles in the previous work . The relationship between the film thickness and the cracked area or the spacing between fragments ,, has been studied experimentally, − theoretically, , and by simulations . This relationship can be used to predict paint film thicknesses in ancient paintings or to understand desiccation patterns in sessile blood drops. , …”

“…28 The relationship between the film thickness and the cracked area or the spacing between fragments 5,19,29 has been studied experimentally, 30−32 theoretically, 29,33 and by simulations. 34 This relationship can be used to predict paint film thicknesses in ancient paintings 35 or to understand desiccation patterns in sessile blood drops. 36,37 In this work, we investigate the effect of notches and film thicknesses by imprinting pyramidal shapes on colloidal films.…”

Crack quasi-healing in films of vertically aligned 1D nanostructures: Impact of compliance in a 1D geometry

“…The cracks thus present geometrical characteristics described by the following parameters: depth, thickness, density, spacing, and aperture. In this way, the crack pattern reveals the mechanical properties of the material 7 and offers a wide variety of applications 8,9 . These patterns have been extensively observed in a variety of materials, such as ceramics, paints or particulate coatings where cracking results from solvent evaporation [10][11][12][13][14][15] .…”