Coating Vaporizing Hydrogel Substrates via Gas-Phase Deposition
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Solution Overview
Problem
Conventional vapor-phase deposition methods, such as ALD, face challenges when coating substrates that evaporate, like hydrogels, as they tend to evaporate during the process, and simultaneous presence of precursor gases leads to particle generation, which is detrimental to the process.
Innovation Solution
A method and device for coating vaporizing substrates by forming gaseous species that undergo chemical deposition reactions in the gaseous phase to produce particulate coatings, allowing for the deposition of film layers on substrates undergoing phase transition from liquid to gas, including hydrogels, with adjustable density and porosity, and optional additional conformal encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ALD methods are used to coat hydrogel substrates, then conformal coatings can be deposited, but the hydrogel substrate evaporates during the process
Solution Approach 1:
The patent changes the fundamental parameters of the deposition process by allowing gas-phase reactions to occur at lower temperatures and shorter timescales, enabling coating of temperature-sensitive substrates like hydrogels that would otherwise evaporate or degrade under conventional ALD conditions
Solution Approach 2:
The substrate is pre-coated with a protective layer or pre-treated to enhance its stability during the deposition process, preventing evaporation and maintaining structural integrity while the coating is being formed
2Productivity
If both precursor substances are simultaneously present in gas phase, then particle generation occurs, but this is detrimental to ALD processes
Solution Approach 1:
The patent employs periodic pulsing of precursor gases into the reaction chamber, ensuring that only one precursor is present in the gas phase at any given time. This temporal separation prevents gas-phase reactions that would generate particles, while maintaining efficient deposition through optimized pulse sequences
Solution Approach 2:
The deposition process is segmented into distinct stages: precursor pulse, purge, and deposition. This segmentation separates the introduction of different precursors in time, preventing their simultaneous presence in the gas phase and eliminating the harmful particle generation effect
3Manufacturing precision
If reactive precursor gases are delivered towards substrate, then coating can be formed, but gas phase reactions generate particles
Solution Approach 1:
The patent uses an inert carrier gas (such as nitrogen or argon) to deliver the precursor vapors to the substrate. This inert atmosphere prevents unwanted gas-phase reactions between precursors and with the environment, eliminating particle generation while maintaining the ability to form conformal coatings through controlled surface reactions
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
Enables controlled release of pharmaceutical agents and biocides with enhanced bioavailability and reduced side effects, and allows for the production of encapsulated substrates with precise release kinetics, tolerating harsh conditions and improving patient compliance.
Implementation Method 1
a film coating comprising at least one coating layer is deposited on at least a portion of a substrate material that undergoes phase transition from essentially liquid phase to gaseous phase
Implementation Method 2
gaseous species, when undergoing chemical deposition reactions in gaseous phase, produce particulate that forms at least one coating layer on at least part of the surface of the substrate
Data Source
AI summary
A method for coating a vaporizing substrate includes depositing a film coating 12 on at least a part of a substrate 10 during the time when the substrate undergoes phase transition from essentially liquid phase to gaseous phase, where the substrate includes a chemical substance that participates in chemical deposition reaction(s) in gaseous phase, the gaseous species 101 formed upon vaporizing at least the portion of the substrate material, when undergoing chemical deposition reactions in gaseous phase, produce particulate 11 that forms at least one coating layer to produce the film coating 12.