Biomimetic design of eco-friendly capsaicin-inspired bifunctional polymer coatings

다국어 초록 (Multilingual Abstract)

A hydrophobic polymer coating with antibacterial and antifouling properties was developed by employing a biomimetic strategy using N-vanillylnonanamide, a capsaicin analog derived from chili pepper. Poly(4-chloromethylstyrene) was first synthesized by free-radical polymerization and was subsequently functionalized via nucleophilic substitution with N-vanillylnonanamide (PEP) to covalently introduce capsaicin-based side chains. A series of polymers (PPEP#, # = 20, 40, 60, 80, and 100) were obtained and their structural, thermal, and mechanical properties were studied. The thin films were fabricated on glass and cellulose substrates by spin- and dip-coating exhibited high optical transparency. As an environmentally friendly alternative to toxic fluorinated compounds, these coatings incorporate bio-inspired molecular structures with functional surface properties. Surface energy measurements and angle-resolved X-ray photoelectron spectroscopy confirmed a progressive increase in surface hydrophobicity with increasing PEP content. The coatings also sealed the porous structure of the cellulose, significantly reducing its water permeability, while maintaining sufficient mechanical integrity and adhesion to the substrate. Antibacterial adhesion tests demonstrated that PPEP100 inhibited Escherichia coli attachment by 100% and Staphylococcus aureus attachment by 92.3%. Long-term adhesion tests under biofilm-promoting conditions further showed that PPEP100 maintained antibacterial adhesion resistance over 7 days. Antifouling assessments using dyes and household contaminants indicated improved performance with increasing PEP substitution, attributed to reduced surface energy and suppressed adsorption.

목차 (Table of Contents)

• Ⅰ. Introduction 1
• 1. Research background 1
• 1.1. Surface fouling 1
• 1.2. Bacterial issues 2
• 1.3. Capsaicin-based functional group 3
• 2. Research objective 4
• Ⅱ. Experimental 7
• 1. Materials and characterization 7
• 2. Synthesis of PPEP# via the substitution of N-vanillylnonanamide 12
• 3. Preparation of films and coated cellulose paper 16
• 4. Evaluation of the water adsorption capacity 16
• 5. Antifouling performance against contaminants 17
• 6. Antibacterial adhesion ability 18
• 7. Stability evaluation of coating films 22
• Ⅲ. Results and discussion 23
• 1. Synthesis and characterization of PPEP# 23
• 2. Thermal performance and stability 36
• 3. Optical and morphological properties 41
• 4. Surface properties and composition analysis 44
• 5. Water resistance of the coated cellulose paper 51
• 6. Antifouling performance 53
• 7. Antibacterial adhesion performance 62
• 8. Stability evaluation 67
• 9. Mechanical properties and adhesion performance 70
• Ⅳ. Conclusions 74
• References 76
• Korean abstract 93