*Article* **Impact of Drying Regimes and Different Coating Layers on Carboxymethyl Cellulose Cross-Linked with Citric Acid on Cotton Thread Fibers for Wound Dressing Modification**

**Mohamad Khalid Khairunnisa-Atiqah <sup>1</sup> , Kushairi Mohd Salleh 1,\*, A. H. Ainul Hafiza 1,2, Nyak Syazwani Nyak Mazlan <sup>1</sup> , Marhaini Mostapha <sup>3</sup> and Sarani Zakaria 1,\***


**Abstract:** The oldest preservation techniques used are drying techniques, which are employed to remove moisture and prevent microorganisms' growths, prolonging a material's shelf life. This study evaluates the effects of drying methods on carboxymethyl cellulose (CMC) + citric acid (CA) coating layers on cotton threads. For this reason, cotton threads were washed and then coated with different layers of CMC cross-linked with CA, followed by drying using an oven (OD), infrared (IR), and a combination of oven + IR (OIR) drying methods at 65 ◦C. Our investigations revealed that CMC + CA yields a pliable biopolymer. The differences in drying regimes and coating layers of CMC + CA have a significant effect on the coated cotton thread strength and absorption capability. The study concluded that the IR drying regime is more effective to dry a single-layered cotton thread with a single layer of CMC + CA coating to enhance desirable properties for wound dressing modification.

**Keywords:** carboxymethyl cellulose; drying effects; wound dressing; coating layers; fiber-based material; mechanical properties
