Rheology and 3D Printing of Emulsion-Filled Hydrogels

Three-dimensional (3D) food printing has emerged as a promising technology for producing customized foods with tailored nutrition, texture, and functionality. The successful fabrication of complex structures using extrusion-based printing requires food inks that can flow easily through a nozzle while retaining their shape after deposition. Achieving this balance remains a significant challenge, particularly for plant-based formulations. Our research focuses on understanding the structure–rheology–printability relationship in emulsion-filled hydrogels prepared using κ-carrageenan, soy protein isolate (SPI), and edible oils. By systematically varying formulation parameters such as polymer concentration, oil-to-water ratio, and thermal processing conditions, we investigate their influence on microstructure, viscoelastic behavior, gel strength, and printing performance. Advanced rheological characterization is employed to quantify shear-thinning behavior, yield stress, and structural recovery, which govern the extrusion and shape fidelity of printed constructs. Statistical optimization techniques are further utilized to identify formulations that provide superior stability and printability. The knowledge generated from this work contributes to the development of sustainable plant-based food materials and provides design guidelines for next-generation printable food systems with improved texture, functionality, and consumer acceptance.

Tough Hydrogels for Biomedical Applications

Tissue engineering is the practice of assembling functional scaffolds that provide cell attachment to replace or improve damaged tissues or whole organs. Three-dimensional (3-D) extrusion printing provides an excellent platform for creating a complex structured tissue engineering scaffold.  Bio-polymeric hydrogels are attractive materials to create bio-scaffolds.  However, due to the lack of mechanical strength of soft biopolymers such as chitosan (CH), it is difficult to fabricate precisely controlled native tissue-mimicking architectures. Various polymers, nanofillers, and crosslinkers are added to improve CH scaffolds' functionality and mechanical strength. Rheological characterization plays a key role in the 3-D printing of soft materials. The printability is primarily ascribed to the rheological properties of shear thinning, adequate viscosity, and yield stress to support the layer-by-layer structure and the excellent fidelity of the filaments. The mechanical strength of the printed filaments should be sufficiently high to self-support and prevent the distortion of the scaffolds induced by the gravity of the deposited filaments. This work aims to improve the CH strength by adding low-quantity graphene oxide nanosheets. The GO-embedded CH hydrogel is proven to be a promising candidate for a tissue engineering application as it supports the differentiation of SH-SY5Y cells.

Concentrated Mineral Slurries 

Various conventional transportation techniques such as trains, trucks, barges, and conveyors for slurry transportation limit the amount of solids and the distance to be transported. On the other hand, the hydraulic conveying of solids in the slurry form through pipelines offers many advantages over other modes of transportation, such as minimum environmental disruption, low air and noise pollution, minimum en-route losses, less space required for installation, low operating and maintenance expenditure, feasible in difficult terrains, and insensitive to the surface conditions. One of the major concerns related to pipeline transportation of slurries is obtaining a favorable flow behavior in terms of minimum energy consumption, frictional head losses, and energy cost when bulk solids are transported through long pipelines. The feasibility of a favorable slurry flow in the pipeline is mainly governed by slurry properties, flowing conditions, and pipeline design parameters. Thus, rheological studies play a crucial role in describing the flow characteristics of the slurry in the pipeline. In collaboration with faculty from materials science, we understand the interplay of surface-active agents, particle concentration, particle size distribution, coarse particle addition, applied shear, time, and temperature on the mineral slurries(coal, fly ash, bauxite, etc.) rheology and subsequently the slurry transportation in pipelines.

Interfacial Engineering

Many daily consumer products, such as creams, are foams or emulsions. A significant challenge is to stabilize these systems as they phase separately over time. The work in the group aims to understand high internal phase emulsions (where the drop phase is greater than 50%) in the presence of proteins as stabilizers.