Award Date

8-15-2025

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Mechanical Engineering

First Committee Member

Hui Zhao

Second Committee Member

Shengjie Zhai

Third Committee Member

Kwang Kim

Fourth Committee Member

Huang Chen

Fifth Committee Member

Hui Zhang

Number of Pages

170

Abstract

Biodegradable polymeric materials (biopolymers) are naturally derived materials known for their excellent biocompatibility, biodegradability, sustainability, and versatile chemical functionality. They have attracted increasing attention in various applications as alternative to synthetic materials ranging from food packaging to tissue engineering. Meanwhile, with intrinsic advantages, biopolymers have also emerged as promising materials in addressing contemporary challenges in both biomedical and environmental fields. Motivated by the significant potential of biopolymers and the growing need for sustainable materials, my research focuses on the design and engineering of biodegradable polymers with novel modification methods and application directions. In this work, two representative biopolymers are selected: silk fibroin, a natural biodegradable protein, and polydopamine (PDA), a synthetic bioinspired polymer, to explore their unique properties and expand their functional application. Especially, this work applies them to addressing critical challenges in sustainable water remediation and wearable bioelectronics, respectively.The first project investigates silk fibroin as a sustainable bioadsorbent for wastewater treatment. Regarding silk fibroin with abundant functional groups, mechanical stability, and biodegradability, it has become an excellent candidate for pollutant removal in natural water resources. To meet the requirements of practical applications, silk fibroin has been integrated into an Automated Drone-Delivery Solar-Driven Water Monitoring and Treatment System (WMTS). This system combines silk bioadsorbents with wireless IoT sensors, cloud-based machine learning, satellite mapping, and autonomous drone deployment to collect and analyze real-time water quality data, then provide optimized and efficient onsite treatment, especially in difficult-to-access locations. This integrated platform offers a closed-loop, energy-efficient, and sustainable solution for managing natural water contamination. The second project focused on polydopamine (PDA), a bioinspired polymer that mimics the strong adhesive properties of mussels. In this part, we develop a self-adhesive, stretchable, and conductive PDA–polyacrylamide (PDA–PAM) hydrogel-based electrode for continuous electrocardiogram (ECG) monitoring. Traditional gel-based silver/silver chloride electrodes often suffer from motion artifacts, signal loss, and skin irritation due to limited adhesion and stretchability. In contrast, the proposed PDA–PAM hydrogel-based electrode offers strong tissue adhesion, excellent flexibility, and intrinsic conductivity, making it an ideal candidate for skin conformal bioelectronic interfaces. Human subject testing demonstrated stable, high-quality ECG signal acquisition with up to 59% improvement in signal-to-noise ratio during intense physical activities, with no skin irritation after prolonged wear. This material shows great promise as a hypoallergenic and durable alternative for next-generation wearable health monitoring devices. In summary, these two projects the versatility and transformative potential of sustainable biopolymers in solving high-impact problems in environmental and health monitoring fields. By utilizing the unique properties of silk fibroin and PDA, this work contributes to the advancement of eco-friendly, human-compatible technologies for both sustainable water remediation and personal health monitoring, reinforcing the role of biopolymers as next-generation materials for a more sustainable future. In response to the COVID-19 pandemic, I also worked on another two side projects focused on disposable face masks. To reduce the risk of fomite-based viral transmission in clinical settings, a superhydrophobic coating of fluorinated graphene (FG) was applied to N95 masks. This simple one-step spray coating dramatically increased water and mucus repellency, improved contact and roll-off angles, and demonstrated strong resistance to SARS-CoV-2-laden body fluid droplets. In another complementary project, I addressed the environmental burden of discarded face masks by repurposing their hydrophobic and superoleophilic properties for oil-water separation. Recycled non-woven masks exhibited high separation efficiency (up to 98.97%) and robustness under harsh conditions, including strong acids, bases, and salty environments. This work offers a practical pathway to mitigate microplastic pollution by turning PPE waste into functional environmental remediation tools.

Controlled Subject

Biopolymers; Land treatment of wastewater; Recycling (Waste, etc.)

Disciplines

Biomechanical Engineering | Biomedical | Biomedical Devices and Instrumentation | Engineering Science and Materials | Environmental Engineering | Materials Science and Engineering

File Format

pdf

File Size

6400 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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