INIDS2-1672
Robust Seawater-Resistant O/W Sunscreen Formulation via Alginate-Cation Crosslinking
Topic
IDS2. Frontiers in Cosmetic Science and Technology (Sponsored by COSMAX)
When and Where
Sep 30, 2026
15:50 - 16:15
Room 102
Session Chairs
Hyerim HWANG
Presenter(s)
Daehwan Park (Jeju National University)
Co-Author(s)
Abstract
Growing outdoor activity and UV awareness increase demand for effective sun protection. UV damages skin, causing sunburn, pigmentation, wrinkles, DNA damage, photoaging, and cancer. Sunscreens must be water-resistant for sweat and water activities. Traditional water-in-oil(W/O) feels heavy and hard to cleanse, while oil-in-water(O/W) washes off and redistributes filters, reducing efficacy. A new approach should form a durable film on skin and anchor UV filters.
We propose a novel O/W sunscreen formulation with improved moisturizing and water resistance properties by exploiting the ion-responsive crosslinking mechanism of sodium alginate, a natural polysaccharide derived from brown algae. Stable film formation was optimized depending on calcium concentrations and the molecular weight of sodium alginate. FTIR confirms Ca2+-carboxylate coordination, while alginate molecular weight(MW) is critical: low-MW causes film tearing and droplet leakage, whereas high-MW yields stronger networks and superior stability. Cross-linking also reduces water evaporation via an occlusive barrier, enhancing moisturization. In real O/W sunscreen and seawater, multivalent cations drive synergistic densification, achieving high water resistance (>90%). In vivo, higher alginate content and robust film retention maintain UV filter and SPF after frictional challenge. Our findings indicate that the developed formulation maintains the favorable sensory characteristics of O/W emulsions while delivering high-performance water resistance particularly optimized for marine environments.
We propose a novel O/W sunscreen formulation with improved moisturizing and water resistance properties by exploiting the ion-responsive crosslinking mechanism of sodium alginate, a natural polysaccharide derived from brown algae. Stable film formation was optimized depending on calcium concentrations and the molecular weight of sodium alginate. FTIR confirms Ca2+-carboxylate coordination, while alginate molecular weight(MW) is critical: low-MW causes film tearing and droplet leakage, whereas high-MW yields stronger networks and superior stability. Cross-linking also reduces water evaporation via an occlusive barrier, enhancing moisturization. In real O/W sunscreen and seawater, multivalent cations drive synergistic densification, achieving high water resistance (>90%). In vivo, higher alginate content and robust film retention maintain UV filter and SPF after frictional challenge. Our findings indicate that the developed formulation maintains the favorable sensory characteristics of O/W emulsions while delivering high-performance water resistance particularly optimized for marine environments.
