Date of Award

8-2025

Document Type

Thesis

Degree Name

Master of Science

Degree Discipline

Chemistry

Abstract

Nanotechnology offers advanced solutions to energy, environmental, and agricultural challenges. Carbon nanotubes (CNTs), with exceptional electrical, mechanical, and sorptive properties, are hindered by hydrophobic graphitic walls that cause bundling in water, limiting green processing. Existing dispersants, 0D surfactants, 1D polymer wraps, and 2D graphene oxide provide only partial stability or require toxic solvents, highlighting the need for a scalable aqueous dispersion. This work investigates polyacrylamide (PAAm) microgels as a three-dimensional (3D) dispersant to stabilize single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs) in water, while producing tunable “jellies” or shear-thinning inks for applications in nutrient retention, soft electronics, and contaminant adsorption. PAAm microgels were synthesized via free-radical precipitation polymerization, mixed with CNTs in water, and probe-sonicated, resulting in stable, self-supporting gels. Characterization confirmed high dispersibility up to 4.8 mgmL⁻¹ SWCNTs and 48 mgmL⁻¹ MWCNTs, while preserving CNT structure and preventing re-bundling. MWCNTs (20–30 nm) formed shear-thinning pastes suitable as

portable inks. Water run-off tests showed 1% drainage after 15 min versus 69% for soil; evaporation over 53 h was 1.7 times slower. TGA indicated enhanced thermal stability for 4-6 nm MWCNT composites due to restricted polymer chain mobility. Biochar failed to induce gelation, confirming the requirement for π-conjugated, high-aspect-ratio frameworks; partial cellulose substitution reduced CNT usage without loss of stability. PAAm microgels present a scalable, tunable 3D platform for CNT dispersion, with potential in sustainable agriculture, environmental remediation, and flexible electronics. PAAm microgels thus offer a scalable, tunable 3D CNT dispersion platform, combining improved water retention, thermal stability, and processability for applications in sustainable agriculture, environmental remediation, and soft electronics. Future work will target fertilizer-release studies, large-scale hydroponics, and bio-derived CNT alternatives.

Keywords: carbon nanotube (CNT); polyacrylamide (PAAm) microgel; three-dimensional (3D) dispersant; single walled carbon nanotube (SWCNT); multi walled carbon nanotubes (MWCNTs); water retention; portable ink; sustainable agriculture

Committee Chair/Advisor

Yunxiang Gao

Committee Member

Ananda Amarasekara

Committee Member

Gururaj Neelgund

Publisher

Prairie View A&M University

Rights

© 2021 Prairie View A & M University

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

Date of Digitization

09/08/2025

Contributing Institution

J. B . Coleman Library

City of Publication

Prairie View

MIME Type

Application/PDF

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