New paradigms with rheologically-complex materials: from protorheology to embedded 3d printing of bioinspired filaments

This dissertation advances the science of soft material characterization and fabrication through three interconnected themes: rheological characterization, fluid mechanics for embedded 3D printing, and bioinspired design. Part I focuses on advanced rheological characterization, where new approaches are introduced to extract meaningful material properties from both conventional and unconventional data sources. A major contribution is the development of protorheology, a paradigm in which rheological properties are inferred from visual data, such as videos or image sequences, thereby enabling high-throughput, non-contact material characterization. In parallel, quantitative guidelines are established to assess the reliability of conventional rheometry, especially in regimes where instrument compliance introduces significant measurement artifacts. Part II addresses the fluid mechanics underlying additive manufacturing techniques, with a focus on embedded 3D printing for soft and reactive materials. Central to this section is the introduction of a new hypothesis for a non-trivial value of the dimensionless critical plastocapillary number that predicts the minimum stable feature size when printing a liquid filament into a yield-stress support medium. This framework establishes a theoretical resolution limit for embedded 3D printing and provides a design criterion for stabilizing fine features. To overcome this limit, a new technique, embedded 3D printing by solvent exchange, is presented, in which rapid solidification is achieved through solvent exchange, allowing the fabrication of structures with diameters well below the plastocapillary threshold. Building on these principles, embedded printing is extended to chemically reactive systems, enabling small feature sizes and architected structures that are otherwise inaccessible via conventional extrusion methods. Part III explores the mechanics of biological and bioinspired fibers, with a focus on the flow-induced deployment dynamics of hagfish slime threads. Rheometric techniques are applied to characterize the physics of unraveling in thread skeins, revealing critical thresholds for successful deployment. Building on these insights, synthetic deployable fibers are created using bioinspired, rather than strictly biomimetic design principles, enabling functional replication of natural hagfish thread skeins behavior. These three paradigms collectively advance how we characterize, fabricate, and design complex soft materials using rheological insight.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Hossain, Mohammad Tanver

Contributors dc:contributor

• Ewoldt, Randy H.
• Ewoldt, Randy H
• Tawfick, Sameh H
• Feng, Jie
• Baur, Jeffery W.

• Embedded 3d Printing
• Plastocapillary
• Hagfish
• Bioinspired Design

Statement dc:rights

• Copyright 2025 Mohammad Tanver Hossain

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/130144

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F130144