Polymer Medical Device Coating via Electrostatic Powder Deposition
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Solution Overview
Problem
Current polymer coating methods for medical devices, such as pacemakers, face challenges with solvent-based and solvent-less processes, including non-uniformity, defects, and inadequate barrier properties against gases and fluids, which can compromise the device's functionality and longevity when implanted in the body.
Innovation Solution
A novel polymer-based coating method involving electrostatic capture of polymer particles followed by sintering with compressed gases, using techniques like e-RESS, e-SEDS, and eDPC, which creates a conformal, defect-free, and uniform seal that is impermeable to gases and fluids, without exposing the device to elevated temperatures or solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional solvent-based polymer coating processes are used, then the coating can be applied to medical devices, but the coating is non-uniform and contains defects such as bare spots, webs, pools, and clumps
Solution Approach 1:
The patent changes the physical state parameter of the polymer coating material from liquid (solvent-based) to solid (powder form). This parameter change eliminates the defects associated with liquid coating application while maintaining effective coating formation through controlled powder deposition and sintering processes
Solution Approach 2:
The patent replaces the chemical solvent-based coating mechanism with a physical powder deposition and sintering mechanism. Instead of using solvents to carry and deposit polymer, the system uses controlled powder delivery followed by thermal sintering to fuse particles into a uniform coating
2Object-affected harmful factors
If solvent-less coating processes such as vapor deposition or plasma deposition are used, then the coating can be applied without solvents, but very aggressive conditions such as elevated temperatures are required that could damage the device
Solution Approach 1:
The patent modifies the thermal processing parameters by using lower temperature sintering conditions compared to traditional solvent-less processes. The powder coating approach allows effective coating formation at temperatures that do not damage sensitive medical device components
Solution Approach 2:
The patent uses a disposable powder coating material that is applied in controlled amounts and then sintered in place. The powder particles serve as temporary individual units during application and then become part of the permanent coating structure after sintering, eliminating the need for expensive reusable coating equipment
3Reliability
If conventional polymer films are used as seals, then the sealing function is provided, but the films are ineffective barriers to the transport of gaseous materials including water vapor
Solution Approach 1:
The patent creates a composite coating structure by incorporating impermeable dispersed solids (such as metal oxides or ceramic particles) within the polymer matrix. This composite approach combines the flexibility and adhesion of polymer with the gas and water vapor impermeability of the dispersed solid particles, creating an effective barrier while maintaining sealing function
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 method provides a reliable, cost-effective seal that shields medical devices from body fluids and gases, ensuring the device's intended function and longevity by preventing degradation and fluid penetration, while maintaining the device's integrity and performance.
Implementation Method 1
electrostatic capture of polymer particles upon a substrate
Implementation Method 2
sintering of these particles by exposure to compressed gasses
Data Source
AI summary
A method for depositing a coating comprising a polymer and impermeable dispersed solid on a substrate, comprising the following steps: discharging at least one impermeable dispersed solid in dry powder form through a first orifice; discharging at least one polymer in dry powder form through a second orifice; depositing the polymer and/or impermeable dispersed solid particles onto said substrate, wherein an electrical potential is maintained between the substrate and the impermeable dispersed solid and/or polymer particles, thereby forming said coating; and sintering said coating under conditions that do not disrupt the activity and/or function of the substrate. A similar method is provided for depositing a coating comprising a hydrophobic polymer and a water-vapor-trapping material on a substrate.