Developing antimicrobial nanocomposites

Zare, Sayeh 2025. Developing antimicrobial nanocomposites. PhD Thesis, Cardiff University. Item availability restricted.

Preview	PDF - Accepted Post-Print Version Download (6MB) | Preview
	PDF (Cardiff University Electronic Publication Form) - Supplemental Material Restricted to Repository staff only Download (491kB)

Abstract

This thesis explores the development and characterisation of polymer-based antimicrobial systems designed to provide antimicrobial activity against antibiotic resistant microorganisms and improve the durability of antibacterial materials. Three distinct polymer systems were synthesised and studied: amino acid–based polysulfonamides (PSAs), poly(diallyldimethylammonium chloride) (PDDA), and quaternised cellulose hydrogels (QC–ECH). The amino acid–based PSAs represent a novel class of polymers in which the sulfonamide motif forms part of the polymer backbone. This design provided enhanced structural stability and potential antimicrobial activity through the properties of the sulfonamide linkage. Characterisation using FTIR and NMR confirmed successful synthesis; however, the materials did not exhibit any discernible antimicrobial activity, indicating that incorporation of the sulfonamide motif alone was insufficient to impart biological function. The PDDA system was modified by incorporating plasticisers (Ionic liquids) and graphene oxide (GO), thereby improving its processability and mechanical resilience. Results from antibacterial assays showed that the PDDA-based nanocomposites exhibited antibacterial activity against the tested bacterial strains. However, the materials displayed limited processability due to thermal degradation occurring before melting, restricting their suitability for extended application or further processing. The quaternised cellulose hydrogel (QC–ECH) was designed to introduce permanent cationic functionality into a biocompatible network. In this work, the material was successfully produced in foam form, representing a new format for this system. The foams were simple to prepare and handle, and their mechanical and antibacterial properties were examined in detail. The material exhibited strong in vitro activity and encouraging ex vivo performance, suggesting its potential for use in tissue engineering and antimicrobial coating applications. The study investigated structure–property–function relationships across three polymer systems through parallel experimental evaluation, to establish a direct link between molecular design, material performance, and practical applicability. This approach not only introduces a new class of polysulfonamides, but also uniquely demonstrates the transformation of PDDA from liquid to solid form with defined thermal behaviour and provides the first detailed mechanical and antibacterial assessment of QC–ECH foams as viable functional materials.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Schools > Engineering
Uncontrolled Keywords:	1. Polymer 2. Antimicrobial Polymers 3. Antimicrobial Nanocomposites 4. Polysulfonamide (PSA) 5. Polyquaternium 6. Cellulose
Date of First Compliant Deposit:	31 March 2026
Last Modified:	01 Apr 2026 08:56
URI:	https://orca.cardiff.ac.uk/id/eprint/186118

Actions (repository staff only)

Edit Item