Capillary Inner Surface Coating via Vapor-Phase Monomer Deposition
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Solution Overview
Problem
Existing methods for coating inner surfaces of enclosed articles, particularly capillaries for capillary electrophoresis, suffer from poor repeatability, reproducibility, high back-pressure, concentration gradients, and low coating consistency due to the use of liquid coatings that degrade quickly and fail to effectively suppress electro-osmotic flow.
Innovation Solution
A method involving vaporization and sequential reaction of monomers to form controlled monomer layers on the inner surface, using molecular layer deposition (MLD) and optionally chemical vapor deposition (CVD) to create a uniform polymeric coating, reducing concentration gradients and improving consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If liquid coating materials are used to coat inner surfaces of capillaries, then the coating process is simple, but the coating consistency and reproducibility are poor
Solution Approach 1:
The patent changes the physical state of the coating material from liquid to vapor phase. This parameter change eliminates concentration gradients and back-pressure issues inherent in liquid coatings, while enabling uniform vapor distribution throughout the capillary. The vapor phase allows the coating material to reach all surfaces evenly, significantly improving coating consistency and reproducibility.
Solution Approach 2:
The patent utilizes phase transition by vaporizing the coating material before introduction into the capillary. The material is heated to transition from liquid to vapor state, allowing it to penetrate and coat the capillary interior uniformly. After coating, the vapor condenses back to liquid or solid form on the capillary surface, forming a consistent coating layer without the defects associated with liquid flushing methods.
2Reliability
If thicker polymeric coatings are applied to suppress electro-osmotic flow, then flow suppression improves, but coating degradation accelerates
Solution Approach 1:
The patent applies multiple thin coating layers sequentially rather than one thick layer. Each layer is deposited independently through vapor phase, allowing for controlled thickness and uniformity. This segmentation approach creates a more stable coating structure where each thin layer adheres properly, preventing the degradation issues seen in thick physiosorbed coatings while maintaining effective electro-osmotic flow suppression.
Solution Approach 2:
The patent replaces the mechanical/physical adsorption mechanism with a chemical vapor deposition mechanism. Instead of relying on physiosorption which leads to rapid degradation, the vapor phase coating creates chemically bonded or strongly adhered layers that are much more stable. This substitution of the coating mechanism fundamentally improves coating durability while maintaining the necessary thickness for flow suppression.
3Quantity of substance
If liquid coating solutions with high viscosity are used, then coating thickness increases, but back-pressure and concentration gradients increase
Solution Approach 1:
The patent uses vapor phase deposition instead of liquid solutions, eliminating viscosity-related back-pressure issues entirely. The coating material is vaporized and introduced as gas, which flows through the capillary without resistance. This phase transition approach allows for effective coating deposition without the high back-pressure and concentration gradients that plague viscous liquid coating solutions.
4Duration of action of stationary object
If silane coatings are applied to provide durable interface, then coating durability improves, but electro-osmotic flow suppression is insufficient
Solution Approach 1:
The patent employs composite coating strategies by combining different coating materials or applying multiple coating layers with different functions. The vapor phase deposition allows for sequential application of silane-based durable layers and additional functional layers that provide electro-osmotic flow suppression. This composite approach integrates the durability of silanes with the flow control properties of thicker polymeric coatings, achieving both objectives simultaneously.
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 achieves a controlled, consistent, and reproducible inner surface coating that reduces capillary blockage and enhances electro-osmotic flow suppression, providing improved analytical results in capillary electrophoresis.
Implementation Method 1
vaporizing a first monomer and reacting the vaporized first monomer with the inner surface of an enclosed article
Implementation Method 2
reacting the vaporized first monomer with the inner surface of an enclosed article to provide a first monomer layer on the inner surface
Implementation Method 3
vaporizing a second monomer and reacting the vaporized second monomer with the first monomer on the inner surface of the enclosed article to provide a second monomer layer
Data Source
AI summary
The present disclosure relates to a method for the production of an inner surface coating on an enclosed article, such as a capillary. the method comprising vaporizing a first monomer and reacting the vaporized first monomer with the inner surface of an enclosed article to provide a monomer layer on the inner surface of the enclosed article. Also disclosed are coated enclosed articles and apparatus for performing the method.