The Effect of Silane Acrylate Containing Ethylene Glycol Chains on the Adhesive Performance and Viscoelastic Behavior of Acrylic Pressure-Sensitive Adhesives for Flexible Displays

In this study, novel silane acrylates, such as diethylene glycol diacrylate (DEGDA) and tetraethylene glycol diacrylate (TEGDA), containing ethylene glycol chains were synthesized and introduced into acrylic pressure-sensitive adhesives (PSAs) to regulate their peel strength and rheological properties. The synthesized silane acrylates effectively improved the cohesion and adhesive properties of the acrylic PSAs, even with only 1 wt% addition. In addition, the glass transition temperature and flexibility of acrylic PSAs were also affected by the increase in free volume induced by ethylene glycol chains. The silane acrylates also improved the viscoelasticity of the acrylic PSAs, which exhibited excellent recovery (62–96%) and stress relaxation (>90%) properties owing to the increased elasticity. Additionally, the acrylic PSAs prepared with the silane acrylates showed excellent optical properties (transmittance ≥ 90%, haze ≤ 1%) and exhibited behavior suitable for application in flexible displays from a comprehensive perspective.