Electrowetting Microfluidic Droplet Control Without External Pumps

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Solution Overview

Problem

Current microfluidic chip technologies rely on external drive pumps for droplet movement, resulting in bulky, costly, and inflexible systems.

Innovation Solution

A microfluidic apparatus with a substrate featuring an electrode array and a hydrophobic layer, where the electrodes are used to apply voltage and control droplet movement within microfluidic channels, eliminating the need for an external drive pump.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an external drive pump is used to extract and move droplets, then droplet movement can be achieved, but the device becomes bulky, costly, and inflexible

Engineering Contradiction:

Improveflexibility of droplet controlVSAvoidsize and structure of the device

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The invention extracts and removes the external drive pump from the system, replacing it with integrated electrowetting electrodes that generate droplet movement forces directly within the microfluidic chip. This eliminates the bulky external pumping mechanism while maintaining droplet transport capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the droplet driving function into the microfluidic substrate by integrating electrode arrays directly into the chip structure. The electrodes are embedded within the substrate layers, combining the pumping function with the fluidic channel structure to create a compact, unified device.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If an external drive pump is used, then droplet transport is possible, but the cost increases and portability decreases

Engineering Contradiction:

Improvedroplet transport reliabilityVSAvoiddevice weight and portability

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The invention replaces the mechanical external pump system with an electrical field-based electrowetting mechanism. Voltage applied to the integrated electrodes creates electrostatic forces that manipulate droplet movement, substituting mechanical pumping with a lighter, more portable electrical control system.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If electrodes are used to control droplet movement, then flexibility and size are improved, but droplet crosstalk from adjacent electrodes may occur

Engineering Contradiction:

Improvedevice integration and sizeVSAvoiddroplet movement path accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The invention introduces a hydrophobic barrier layer positioned between adjacent microfluidic channels and electrodes. This hydrophobic layer acts as an intermediary that prevents electrical field crosstalk and droplet leakage between neighboring channels, ensuring precise droplet confinement and movement control.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Manufacturing precision

If a integrated microfluidic structure layer is added to define channels, then droplet path control improves, but manufacturing complexity increases

Engineering Contradiction:

Improvedroplet movement path definitionVSAvoidmanufacturing process complexity

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention segments the microfluidic device into distinct functional layers: a microfluidic substrate with integrated electrodes, a hydrophobic barrier layer, and a microfluidic structure layer with defined channels. This layered segmentation allows each component to be manufactured and optimized independently before assembly, simplifying the overall manufacturing process while maintaining precise channel definition.

Inventive Principle:

Principle #1Segmentation

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 achieves a compact, cost-effective, and flexible control of droplet movement, integrating the system as a whole and reducing product costs while maintaining high accuracy and portability.

Implementation Method 1

the electrode array layer includes a plurality of electrodes arranged in an array... apply a voltage to each of the plurality of electrodes... to drive a droplet in each of the at least one microfluidic channels to move

Methodology Applied

Scientific EffectElectrowetting: Electrowetting

Implementation Method 2

a hydrophobic layer... prevent the droplet from crosstalk caused by adjacent electrodes

Methodology Applied

Scientific EffectHydrophobic effect: Hydrophobe

Data Source

PatentUS12311365B2Microfluidic apparatus and manufacturing method thereof

Publication Date: 2025.05.27 SHANGHAI TIANMA MICRO ELECTRONICS CO LTD

AI summary

Provided are a microfluidic apparatus and a manufacturing method thereof. The microfluidic apparatus includes a microfluidic substrate including a base substrate, an electrode array layer located on the base substrate, and a hydrophobic layer, where the electrode array layer includes a plurality of electrodes arranged in an array; and a microfluidic structure layer including at least one microfluidic channel; where the microfluidic substrate is configured to apply a voltage to each of the plurality of electrodes according to the at least one microfluidic channel to drive a droplet in each of the at least one microfluidic channels to move.