3D Phononic-Fluidic Systems for Liquid Mixture Analysis and Control

• Applicant: Professor Dr. Frieder Lucklum
• Subject Area: Microsystems ; Acoustics ; Mechanical Properties of Metallic Materials and their Microstructural Origins ; Measurement Systems
• Term: from 2019 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 413261500

This project aims at a fundamentally new class of microsystems, namely phononic-fluidic systems, by combining acoustically significant microstructures with microfluidic elements containing exchangeable analytes. This combination will pave the way for a new class of devices for the acoustic analysis and control of a variety of fluids, from simple liquids like water and alcohols, clean mixtures and solutions to complex liquids like cell cultures or blood. Understanding elastic and acoustic wave propagation and resonance phenomena in such microstructured materials is the theoretical foundation of these devices. The rapidly growing possibilities of additive manufacturing form the enabling technological basis to realize complex 3D geometries and integration of multiple functionalities in single parts.Phononic crystals, acoustic equivalent of photonic crystals from optics, offer unique band structures to manipulate acoustic wave propagation. Additive fabrication will be used to realize 3D phononic crystals with band gap characteristics beyond the capabilities of corresponding 2D designs. Likewise, adding fluidic features into a phononic lattice as defects will be the first device concept explored in this work. A phononic-fluidic cavity defect acts as an acoustic resonator that combines the high sensitivity of resonant sensors with the ability of ultrasonic sensors to probe volumetric properties of fluids. The cavity defect resonance will be designed to fall into a phononic band gap and yield a highly sensitive and unperturbed resonance peak dependent on the physical properties of the liquid analyte, such as speed of sound, density, viscosity, and concentration.Further research will include a fully three-dimensional approach to arrange phononic structures around and inside fluidic elements. This will enable fundamentally new devices ultimately combining different physical functionalities within a single structural element. Waveguide structures will be introduced into a phononic lattice around a microchannel to precisely focus acoustic energy into arbitrary locations, resulting in a unique spatial resolution of the fluid flow. Finally, periodic microstructures integrated inside a microchannel will for the first time simultaneously act as fluidic filter and acoustic particle detector.In summary, significant objectives of the project include:1. Theoretical and technological foundation for design, realization and characterization of 3D phononic crystals with optimized band structures.2. 3D phononic-fluidic cavity sensors as highly sensitive methodology for localized measurement of volumetric properties of liquids and mixtures.3. Groundbreaking fusion of multiple physical functionalities in single structural elements by integrating (sub-)micron phononic-fluidic elements for particle detection and manipulation.

• DFG Programme: Research Grants
• International Connection: Denmark