Thin Film Fabrication with Combined Dip and Atomized Spray Deposition
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Solution Overview
Problem
Existing layer-by-layer (LbL) deposition methods for thin films are time-consuming and inefficient, particularly dip coating, which takes days to form multiple layers due to slow equilibrium adsorption, while spin and spray coating struggle with uniformity and waste, making them unsuitable for irregular or 3D substrates.
Innovation Solution
A combined method and apparatus that includes both immersion in a charged solution and spraying with an atomized charged solution, allowing for faster layer formation without compromising homogeneity, suitable for various substrate shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dip coating is used for LbL deposition, then homogeneous and stable layers are formed, but the process is time-consuming taking days to form multiple layers
Solution Approach 1:
The patent combines dip coating and spray coating into a sequential process where dip coating forms the base layer and spray coating adds subsequent layers, merging the advantages of both methods to achieve both homogeneity and speed
Solution Approach 2:
The invention uses periodic alternation between immersion and spray steps, creating a rhythm of slow homogeneous deposition followed by fast layer building, repeating this cycle to achieve both quality and efficiency
2Productivity
If spray coating is used for LbL deposition, then deposition speed is increased, but layer homogeneity and stability are compromised
Solution Approach 1:
The patent performs preliminary dip coating to create a stable base layer with homogeneous charge distribution before applying spray coating, preparing the surface to receive subsequent spray-deposited layers uniformly
Solution Approach 2:
The invention applies different coating methods to different stages of layer formation: dip coating for the initial base layer where homogeneity is critical, and spray coating for subsequent layers where speed is more important, optimizing each stage locally
3Productivity
If spray coating is used for LbL deposition, then deposition speed is increased, but material waste increases significantly
Solution Approach 1:
The patent extracts and removes the excess charged solution from the spray coating process through a separate waste collection system, separating the useful deposited layer from the wasted material for potential recovery or proper disposal
4Manufacturing precision
If dip coating is used for LbL deposition, then complete surface coverage is achieved, but the depletion zone delays adsorption increasing process time
Solution Approach 1:
The patent uses spray coating to skip through the slow diffusion process through the depletion zone by directly depositing charged solution onto the surface, bypassing the time-consuming equilibrium adsorption phase while maintaining coverage
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The combined method reduces the time required to build up multiple layers by leveraging the speed of spray coating while maintaining the stability and uniformity of dip coating, enabling efficient deposition on 3D substrates with reduced material waste and cost.
Implementation Method 1
a pre-charged substrate to be coated is dipped into a reservoir of charged solutions. As the substrate is dipped into the reservoir of charged solution the layer is formed by electrostatic interaction between substrate and charged solution.
Implementation Method 2
spraying the substrate with an atomized charged solution to deposit a layer on the substrate
Implementation Method 3
The kinetics of the molecules means it takes a long time to build up a layer. This is because the time required to reach equilibrium adsorption for each coating step is relatively high compared to other techniques.
Data Source
AI summary
A method of layer-by-layer deposition for thin-film fabrication and a layer-by-layer deposition apparatus for thin-film fabrication. The method comprises the steps of at least partially immersing a substrate in a reservoir of a charged solution to deposit a layer on the substrate and spraying the substrate with an atomized charged solution to deposit a layer on the substrate.