Thermotion: Design and fabrication of thermofluidic composites for animation effects on object surfaces

Paper Title

Thermotion: Design and Fabrication of Thermofluidic Composites for Animation Effects on Object Surfaces

Paper Information

• Research Domain: Human-Computer Interaction, Thermofluidic Composites, Dynamic Display Design
• Keywords: Thermochromic Interface, Thermofluidic Composites, Thermal Design, Programmable Materials, Computational Design, Human-Material Interaction

Research Background and Problem Statement

• Identified Problems or Challenges:

  1. Most current color-changing interfaces rely on electronic components (e.g., resistive heaters and Peltier elements) to activate thermochromic paints. However, these methods only support localized uniform color changes, and complex circuits struggle to achieve dynamic and detailed animation effects.
  2. Dynamic interfaces created using photochromic and fluid materials also face limitations, such as dependency on transparent or optical materials.
  3. There is a lack of design and fabrication workflows capable of achieving dynamic displays on complex shapes and surfaces compatible with everyday materials.

• Significance of the Research: Dynamic color-changing interfaces can expand the functionality of physical interfaces, enabling interaction and applications on flexible everyday materials and surfaces with complex two-dimensional and three-dimensional shapes.

• Motivation and Related Work: Inspired by the flexibility and dynamic capabilities of thermofluidic control, the study aims to develop a design method for interfaces that achieve dynamic color changes and are adaptable to everyday materials.

Solution

• Proposed Method or Solution: The authors propose a method based on thermofluidic composites (incorporating embedded fluid channels) to achieve dynamic color-changing animation effects by controlling the temperature variations of thermochromic paint.

• Innovations:

  • Utilizing thermofluidic systems instead of traditional electronic components to control temperature, enabling dynamic programmable animation effects.
  • Addressing compatibility issues with complex curved surfaces, three-dimensional shapes, and flexible everyday materials such as paper and fabric.
  • Providing a customized design tool for structuring fluid channels and simulating real-time animation effects.

• Implementation Steps and Key Techniques:

  1. Composite Material Structure: Thermofluidic composites consist of four layers: channel layer, fluid layer, thermal diffusion layer, and coating layer.
  2. Thermochromic Performance Testing: Quantitative analysis of the thermochromic performance of the composite material, validating the enhancement of smooth color transitions by the thermal diffusion layer.
  3. Animation Effect Design: Defined six animation primitives (e.g., erasure, diffusion, texture effects, paths) and two embellishment effects (e.g., blur effects, multicolor effects).
  4. Design Tool and Simulation: Developed a tool based on the finite volume method (FVM) for designing and simulating thermofluidic flow animation effects.
  5. Fabrication Process: Includes 3D printing or silicone casting of the fluid channel layer, assembly of the thermal diffusion layer and coating layer, and generation of the fluid layer.

Research Outcomes

• Specific Results:

  • Successfully implemented the four-layer base structure of thermofluidic composites.
  • Proposed multiple dynamic display design spaces, including animation primitives and embellishment effects.
  • Designed and realized a fabrication process compatible with flexible everyday materials.
  • Developed a customized tool supporting geometric design and animation simulation, with verified accuracy.

• Comparison with Existing Solutions:

  • Compared to designs based on electronic components, the thermofluidic approach significantly reduces circuit complexity and adapts to more shapes and materials.
  • Compared to photochromic and transparent fluid interfaces, it offers dynamic display compatibility with everyday materials.

• Experimental or Evaluation Results:

  • Simulation results showed a deviation of no more than 1.2°C from actual measurements, demonstrating the reliability of the design tool.
  • High repeatability in the fabrication process, with a total of 96 devices manufactured.
  • Evaluated device repeatability, durability, and supported minimum dimensions (4×3×2mm³) and thickness (5mm).

• Limitations and Future Directions:

  • Limitations:
    • Thermofluidic systems currently operate in open-loop control, leading to precision issues.
    • Fabrication processes impose constraints on material properties and thickness.
    • Some simulation parameters rely on empirical estimation, leaving room for optimization in simulation accuracy.
  • Future Directions:
    • Integrate more miniaturized and autonomous functionalities into thermofluidic systems.
    • Investigate microscale thermofluidic technologies to support higher-resolution animations.
    • Extend this system to other thermally responsive materials (e.g., shape transformation) and apply it to wearable devices and more complex dynamic display interfaces.