Microfluidic Freshening Composition to Reduce Thermal Nozzle Clogging
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Solution Overview
Problem
Thermally-activated microfluidic devices used for delivering freshening compositions often experience nozzle clogging due to solidification of fluid compositions, leading to decreased flow rates and increased operating times.
Innovation Solution
A microfluidic cartridge with a reservoir containing a fluid composition comprising greater than 5 wt.% of solubilizing materials with specific Hansen polarity and hydrogen-bonding parameters, and low vapor pressure, which are designed to minimize clogging by regulating evaporation and preventing solidification on the nozzle surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fluid compositions are used in thermally-activated microfluidic devices, then the device can deliver freshening compositions into the air, but nozzle clogging occurs after repeated use due to solidification of the fluid composition
Solution Approach 1:
The patent changes the chemical composition parameters of the fluid by incorporating solubilizing materials with specific Hansen solubility parameters (δp > 5 MPa^0.5, δh > 9 MPa^0.5) and controlling vapor pressure (< 267 Pa at 25°C). This modifies the fluid's physical properties to prevent solidification and clogging while maintaining delivery effectiveness.
Solution Approach 2:
The patent creates a composite fluid composition combining freshening agents with specific solubilizing materials (such as phenylmethanol, 2-(2-hydroxypropoxy)propan-1-ol, propane-1,2-diol, and other hydroxy-containing compounds). This composite formulation prevents solidification on nozzle surfaces while maintaining the freshening function.
2Productivity
If nozzle clogging occurs, then flow rate decreases and operating time increases to compensate, but the clogged nozzle cannot be easily cleared
Solution Approach 1:
The patent applies preliminary action by formulating the fluid composition with solubilizing materials before use to prevent solidification and clogging from occurring in the first place. The specific composition (greater than 5 wt% solubilizing materials with controlled vapor pressure and Hansen parameters) proactively maintains fluid flow properties throughout device operation.
3Productivity
If the fluid composition is heated for atomization, then delivery efficiency improves, but solidification on the nozzle surface occurs leading to blockages
Solution Approach 1:
The solubilizing materials act as intermediaries between the freshening agents and the thermal atomization process. These materials (with specific Hansen parameters and low vapor pressure) mediate the heating process by preventing solidification on nozzle surfaces while allowing efficient atomization to occur.
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 solution effectively reduces nozzle blockages and maintains consistent flow rates by using solubilizing materials that prevent solidification and gel formation on the microfluidic die, ensuring efficient atomization and delivery of freshening compositions.
Implementation Method 1
solubilizing materials that are liquid at 20° C., the solubilizing materials each having: a Hansen polarity parameter (δp) of greater than 5 MPa0.5; a Hansen hydrogen-bonding parameter (δh) of greater than 9 MPa0.5; and a vapor pressure of less than 267 Pa, measured at 25° C.
Implementation Method 2
heating the composition with a thermal actuator; atomizing the heated composition from a nozzle
Implementation Method 3
atomizing the heated composition from a nozzle in a direction that is from 0 degrees to 90 degrees from the direction of gravitational force
Data Source
AI summary
A freshening composition and method of jetting a freshening composition from a microfluidic device are provided. The composition includes greater than 5 wt. % of solubilizing materials that are liquid at 20° C. Each of the solubilizing materials have a Hansen polarity parameter (δp) of greater than 5 MPa0.5; a Hansen hydrogen-bonding parameter (δh) of greater than 9 MPa0.5; and a vapor pressure of less than 267 Pa. The method includes heating the freshening composition with a thermal actuator and atomizing the heated composition from a nozzle in a direction that is from 0 degrees to 90 degrees from the direction of gravitational force.