03/21/2025
By Danielle Fretwell
Date: Friday, April 4, 2025
Time: 3 - 5 p.m.
Location: Perry Hall 215
Committee:
Advisor: Amir Ameli, Associate Professor, Plastics Engineering, UMass Lowell
Committee Members*
1. Ramaswamy Nagarajan, Distinguished Professor, Plastics Engineering, UMass Lowell
2. Jay Park, Associate Professor, Plastics Engineering, UMass Lowell
Brief Abstract:
Ph.D. Proposal: Leveraging Thermally Expandable Microspheres for Advanced Materials
This proposal outlines a research program focused on exploring the unique properties of thermally expandable microspheres (TEMs) to develop novel foams with enhanced functionalities. TEMs, upon heating, undergo significant volume expansion, offering a versatile platform for creating foams with tailored microstructures and properties. This research will encompass three distinct yet interconnected chapters, each building upon the fundamental understanding of TEM-induced material modifications.
Chapter 1: Pressure Sensors with Tunable Density and Electrical Conductivity
This chapter will investigate the development of pressure sensors utilizing TEMs. In a bid to achieve low density foam while preserving required electrical conductivity for high sensitivity in pressure sensing, we designed a facile one-pot fabrication of conductive foams in which a segregated conductive network of graphene nanoplatelets reside around TEMs. This research will focus on optimizing composition and processing parameters to achieve desired sensor characteristics for applications in wearable electronics, robotics, and healthcare.
Chapter 2: Energy Efficient Plant-Based Sustainable Cellulosic Foam via Air-Drying
Building upon the understanding of TEM-induced structural modifications, this chapter will explore the fabrication of lightweight and high-performance cellulosic foams. By incorporating TEMs into a cellulose-based matrix and subjecting it to a controlled air drying, we aim to create foams with tailored porosity, mechanical properties, and insulative characteristics that has an energy efficient fabrication process and utilized sustainable materials. The core of this research is eliminating freeze-drying that is used for the current porous cellulosic materials, which is time and energy intensive. Also, the influence of TEM concentration, other additives, and processing conditions on the foam's microstructure and performance will be investigated.
Chapter 3: Direct ink Writing of Functional Cellulosic Nanocomposites
This chapter will build upon Chapter 1 and 2 and extend the application of TEMs to 3D-printing of functional cellulosic nanocomposite foams via air drying. By incorporating TEMs and other functional nanomaterials (e.g., MXenes, graphene, carbon nanotubes) into a cellulose-based ink, we aim to 3D-print complex structures with tailored properties. The controlled morphological and rheological properties during the 3D-printing process will enable the fabrication of lightweight and porous structures with enhanced mechanical strength and functional properties. This research will focus on developing 3D-printing protocols and optimizing the ink formulation to achieve precise control over the final structure and properties of the printed objects while minimizing the shrinkage.