Harnessing Self-Assembly for Integrating Structural Color in Additive Manufacturing

About This Grant

Color is essential to communication, identification, and technology, yet most manufactured colors rely on chemical pigments and dyes that fade over time, generate waste, and require environmentally harmful processing. In contrast, many natural systems produce color through precisely organized microstructures that interact with light, creating vibrant and durable effects without chemical colorants. However, manufacturing such microstructure-based color in scalable, customizable ways remains a major challenge, particularly for additive manufacturing technologies that are widely used for rapid prototyping and distributed production. This project seeks to establish new scientific principles for producing durable, tunable color directly during additive manufacturing by controlling how microscopic material structures form on printed surfaces. Rather than depositing multiple colored materials or using chemical dyes, the approach enables color to emerge from physical structure alone. This capability would reduce material waste, simplify manufacturing systems, and expand the functionality of additively manufactured parts. The project supports national priorities by advancing manufacturing efficiency, strengthening domestic innovation in advanced materials, and enabling new capabilities for applications such as secure identification, sensing, energy-efficient displays, and adaptive surfaces. Educational and workforce development activities will train students and researchers at the intersection of manufacturing, materials science, and data-driven design, while outreach efforts will broaden participation in emerging areas of functional materials and advanced manufacturing. The overall goal of this project is to enable programmable structural color in additively manufactured materials by directing microstructure formation during material extrusion and curing. The research is guided by the hypothesis that printable inks can be engineered so that macroscopic shape formation and microscopic particle organization occur simultaneously, allowing optical functionality to emerge during fabrication rather than as a post-processing step. Achieving this requires understanding and controlling non-equilibrium assembly processes at material interfaces under flow, external fields, and evolving material properties. The research plan integrates experiments, theory, and data-driven modeling to resolve how rheology, particle interactions, and external stimuli govern surface microstructure evolution. Specific aims are to: (1) characterize the coupled effects of material flow and curing on surface microstructure formation during extrusion; (2) determine how electrically and thermally mediated interactions can be used to direct particle organization for tunable optical response; and (3) develop real-time feedback strategies that adapt processing conditions to achieve target optical properties on demand. Success will be demonstrated through controlled reflectance across the visible spectrum, improved angular color stability, and reproducible microstructural ordering across printed surfaces. The outcomes will establish generalizable design rules for coupling additive manufacturing with directed microstructure formation, advancing the broader fields of manufacturing science, soft matter physics, and functional materials. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.