Adhesive

Adhesion

Polymer chemistry

Materials science

Layer (electronics)

Viscoelasticity

Polymer

Thermodynamics

Physics

Dielectric

Dynamic mechanical analysis

Elastic modulus

Composite material

Loss factor

Atmospheric temperature range

Optoelectronics

Dynamic modulus

Advanced Functional Materials

Loss factor tan δ determines the viscoelasticity of a material. Higher or lower loss factor tanδ (&gt;1 or &lt;1) suggests a viscous or elastic material. Most polymer pressure‐sensitive adhesives (PSAs) possess a limited operational temperature range (near room temperature), above which the PSAs trend to be more viscous (un‐crosslinked) or more elastic (crosslinked), and below which PSAs become more elastic. These properties are unfavorable for PSA operation. Herein, an underwater PSA possessing short hydrophobic side chains and weak hydrogen bond interactions are described. Proper modulus and stable loss factor close to 1 contributes to an efficient adhesion underwater over a temperature range of 0–100 °C. Moreover, by introducing Teflon particles, the adhesion can be operated under silicon oil from room temperature to 150 °C due to the formation of a drainage surface structure and its temperature insensitivity.

Polymer Pressure‐Sensitive Adhesive with A Temperature‐Insensitive Loss Factor Operating Under Water and Oil