Development of Carrageenan Based Polyaniline/Titanium Dioxide Films with Improved Antibacterial and Mechanical Properties

Soo, Wen Xing (2025) Development of Carrageenan Based Polyaniline/Titanium Dioxide Films with Improved Antibacterial and Mechanical Properties. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

Traditional wound dressings often rely on antibiotics as their primary antibacterial agent and use petroleum-based plastic. These contribute to bacterial resistance and environmental pollution. In this study, kappa-carrageenan (κ-CGN), a biodegradable polymer, serves as both film matrix and antibacterial agent whereas polyaniline (PAni) acts as the primary antibacterial agent. Titanium dioxide (TiO2) was added to improve the film’s antibacterial efficacy and mechanical strength. PAni and PAni-TiO2-10% samples were synthesized at 0°C using a chemical oxidation method. TiO2 was added during polymerization of PAni (in situ-polymerization) and after polymerization of PAni (ex situ-polymerization) then mixed with κ-CGN individually to form films, named as κ-CGN/PAni-TiO2-10%(i) and κ-CGN/PAni-TiO2-10%(e), respectively. FTIR spectra confirmed the chemical structures of PAni, PAni-TiO2-10%, PAni/HCl/κ-CGN, κ-CGN/PAni-TiO2-10%(i) and κ-CGN/PAni-TiO2-10% (e) films. The UV-Vis spectra for both PAni and PAni-TiO2-10% proved that they were conducting emeraldine salt form by showing 3 peaks at 325-333nm, 467-463nm, 875-878nm that corresponds to π-π*, polaron-π* and π-polaron transition. The conductive emeraldine state for both PAni and PAni-TiO2-10% were further confirmed by the resistivity meter analysis by possessing high electrical conductivity of 16.232 S/cm and 9.024 S/cm, respectively. The antibacterial activity of the films was tested against different types of Gram-negative (P. mirabilis, P. aeruginosa and E. coli) and Gram-positive bacteria (S. aureus, B. subtilis and L. monocytogenes). PAni/HCl/κ-CGN film showed inhibition of 17.16% against S. aureus and 16.25% against P. mirabilis because of PAni disrupted bacterial membranes via electrostatic interaction. TiO2 played its role in suppressing the bacterial in which κ-CGN/PAni-TiO2-10%(e) showed 10.66-11.45% inhibition against P. mirabilis with and without UV irradiation while κ-CGN/PAni-TiO2-10%(i) showed zero inhibition. All PAni films possess tensile strength of 17.82-22.80 MPa, Young’s modulus of 54.89-88.96 MPa and elongation at break of 27.45-46.20% in which they fulfilled the basic requirement for the mechanical properties of plaster used for wound dressing.