DMREF/Collaborative Research: Acoustically Transformative Materials

许多研究都集中在开发常规声学应用的材料上，如超声成像、隔音和地质测井。然而，积极响应声音并同时改变其声学和光学特性的材料设计仍处于起步阶段。这个项目的目标是设计声响应材料，当它们与声波相互作用时，改变它们的化学结构、物理性质和物体形状，从而实现声特性的主动调制，包括声速、衰减和声子带隙。如果与电磁辐射相比，声波具有独特的物理特性，因为它们很容易通过光学不透明的材料传播，包括液体、固体和凝胶（例如人体），而传统刺激（如光和电场）的直接应用在物理上或生理上都是禁止的。这使得对各种材料特性的非侵入性询问和各种机械化学过程的远程激活成为可能。此外，与电磁辐射类似，声音可以在空间和时间上集中。这为以时间控制的顺序方式执行局部修改提供了有趣的机会。这些材料可用于声学光刻和自我修复的材料工程，以及生物医学应用，包括非侵入性手术、诊断和药物输送。技术概述：该项目的目标是在材料设计中发展一个新的方向，其中材料特性的基本变化是由声波激活的，声波同时改变宏观物体的声学、光学和几何特征。研究活动追求三个战略目标。首先，对复杂大分子的多尺度结构与这些分子介块组装的材料的力学性能之间的层次关系有基本的理解。理论研究将为合成具有非常广泛的弹性、强度和韧性的材料提供指导，这些材料目前在传统聚合物体系中是不可用的。其次，研究声波与刺激响应聚合物体系的相互作用，探索不同的激活机制，改变密度、模量、压缩率和形状。理解声学触发的材料特性变化和声学特性的相应变化之间的反馈是本提案的一个智力挑战。第三，创造一种新型材料，可以通过可编程和时间分辨的方式使用声场来远程激活、驱动和导航。这个项目的预期高潮是声学转换材料，不仅对声音做出反应，而且从根本上改变它们的物理性质、物体尺寸、声学和光学特性。该项目的合作性质将确保初级研究人员在聚合物合成、物理实验和理论方面的跨学科培训。该项目还为扩大代表性不足群体的参与和促进合作研究的基础设施提供了机会。

NON-TECHNICAL SUMMARYMany studies have focused on developing materials for conventional acoustic applications, such as ultrasound imaging, sound insulation, and geological logging. However, the design of materials that actively respond to sound and concurrently shift their acoustic and optical characteristics remains in its infancy. The goal of this project is to design acoustically responsive materials that alter their chemical structure, physical properties, and object shapes whenever they interact with sound waves enabling active modulation of acoustic properties including speed of sound, attenuation, and phononic band gaps. If compared to electromagnetic radiation, sound waves possess unique physical characteristics as they readily propagate through optically non-transparent materials, including liquids, solids, and gels (e.g., human body), where direct application of conventional stimuli, such as light and electric fields, is either physically or physiologically prohibited. This enables non-invasive interrogation of a wide range of materials properties and remote activation of various mechanochemical processes. Moreover, similar to electromagnetic radiation, sound can be focused both in space and in time. This opens intriguing opportunities to perform local modifications in a time-controlled, sequential manner. These materials may be utilized both in materials engineering for acoustic lithography and self-healing and in biomedical applications including non-invasive surgery, diagnostics, and drug-delivery. TECHNICAL SUMMARYThe project goal is to develop a new direction in materials design wherein fundamental changes in materials properties are activated by sound waves that concurrently shift acoustic, optical, and geometric characteristics of macroscopic objects. The research activities pursue three strategic objectives. First, develop fundamental understanding of hierarchic correlations between the multi-scale architecture of complex macromolecules and mechanical properties of materials assembled of these molecular mesoblocks. Theoretical studies will provide guidelines for synthesis of materials with an extraordinarily broad range of elasticity, strength, and toughness that are currently not available in conventional polymer systems. Second, study the interaction of sound waves with stimuli responsive polymer systems and explore different activation mechanisms that shift density, modulus, compressibility, and shape. Understanding the feedback between acoustically triggered changes in materials properties and the corresponding shifts in acoustic characteristics represents an intellectual challenge of this proposal. Third, create a novel class of materials that can be activated, actuated, and navigated remotely using acoustic fields in a programmable and time-resolved manner. An anticipated culmination of this project is acoustically transformative materials that not only respond to sound but also fundamentally change their physical properties, object dimensions, and acoustic and optical characteristics. The collaborative nature of this project will ensure interdisciplinary training of junior researchers in polymer synthesis, physical experiments, and theory. The project also provides opportunity for broadening participation of underrepresented groups and fostering infrastructure for collaborative research.