Antibacterial Cotton via Chitosan Finishing
Testing durability of a natural antibacterial finish across wash cycles
Overview
A wash-durability study of chitosan-based antibacterial finishing on cotton fabric, evaluated against quantitative bacterial reduction standards.
Problem
Antibacterial finishes are often marketed on a single fresh-fabric test, with wash durability left unreported.
Objective
Quantify how chitosan-based antibacterial finish performance decays across repeated domestic laundering.
Methodology
Pad-dry-cure application of a chitosan solution on bleached cotton, followed by AATCC 100 bacterial reduction testing at 0, 10, 20, and 30 wash cycles against S. aureus and E. coli cultures.
Materials
100% cotton bleached fabric, chitosan (medium molecular weight), acetic acid solvent system, standard laundering detergent.
Experimental Design
Three fabric batches per wash-cycle interval, tested in triplicate to control for finish application variance.
Results
Bacterial reduction stayed above 90% through 10 wash cycles, dropping to roughly 65% by cycle 30 — a decay curve consistent with finish leaching rather than mechanical damage.
Conclusion
Chitosan finishing is durable enough for short-cycle-replacement textiles like medical gowns, but not for garments expected to survive 30+ wash cycles without reapplication.
Future Work
Compare against a cross-linked chitosan variant to test whether covalent bonding meaningfully extends durability.