From interfacial nanostructures to advanced constructs: harnessing surfactant self-assembly at liquid interfaces
No Thumbnail Available
Authors
Meeting name
Sponsors
Date
Journal Title
Format
Thesis
Subject
Abstract
Liquid-in-liquid 3D (LL3DP) printing offers a promising platform for fabricating soft material structures by depositing an ink phase within an immiscible support bath. While this technique enables the creation of complex architectures for applications in biomedical engineering, drug delivery, and tissue scaffolding, its broader potential is currently limited by the stability and tunability of the liquid-liquid interface. The primary focus of this work is to develop and stabilize structured liquid interfaces that can support and facilitate LL3DP, enabling more reliable and versatile printing of soft materials. By designing material systems with enhanced interfacial stability and responsiveness, this approach aims to expand the library of printable inks and unlock new possibilities for controlled soft matter fabrication. In the first studied system, we investigate the stabilization of the liquid–liquid interface to fabricate a bicontinuous interfacially jammed emulsion gel (bijel) using the LL3DP approach. The bijel consists of two interpenetrating, continuous phases of immiscible liquids, stabilized by the self-assembly of colloidal particles—primarily nanoparticles— at the liquid interface. The structural features of the printed bijel constructs are characterized using confocal and scanning electron microscopy (SEM), while their mechanical properties are evaluated through shear rheometry. Compared to other soft materials explored for LL3DP, bijel-based prints offer unique advantages, including interconnected hydrophobic and hydrophilic domains confined within defined geometries, along with tunable structural and rheological characteristics. In the second system, a novel material system based on lipid self-assembly is presented to stabilize water-oil interfaces as the underlying mechanism in the LL3DP. The stabilization process, governed by the formation of nanostructures at the interface, is comprehensively analyzed using small-angle X-ray scattering (SAXS), rheometry, and microscopy techniques. This material system, once incorporated successfully in LL3DP, enables the fabrication of intricate 3D constructs, including fibers, substrates, and microneedle patches, which demonstrate exceptional mechanical properties and biocompatibility, as validated by tensile testing and cell viability assays. Finally, the incorporation of silica nanoparticles into a material system previously established for soft matter 3D printing is presented, which was shown to result in the formation of aerogels with significantly enhanced mechanical strength and stability. Such silica aerogels, known for their ultralight weight and high porosity, tend to reinforce the liquid-phase structures while preserving flexibility. Upon further characterization, SAXS measurements confirm improved nanostructural organization in these aerogels, while rheological properties are comprehensively characterized. The development of these aerogels with hierarchical ordering across multiple length scales opens new possibilities for designing high-performance, multifunctional materials for medical implants, tissue engineering scaffolds, and filtration systems. This thesis, by bridging 3D printing and interfacial stabilization through selfassembly of various colloidal components such as inorganic (silica) nanoparticles and small amphiphilic molecules, lays the foundation for future advancements in soft material fabrication. The precise control over liquid-phase architectures and their tailored mechanical properties, as well as structural ordering at various scales, offers new possibilities for designing new class of materials for medicine, biotechnology, and advanced manufacturing.
Table of Contents
Introduction -- Fabrication of bijels via solvent transfer induced phase separation using liquid-in-liquid printing -- Application of lipid-stabilized liquid-liquid interfaces in 3D printing of biomaterials -- Freeze-dried lyotropic liquid crystal aerogels with tunable lamellar morphology and mechanical properties -- Conclusions and future work
DOI
PubMed ID
Degree
Ph.D. (Doctor of Philosophy)