Enhancing Adhesion On-Demand in Bottlebrush Pressure Sensitive Adhesives

Area of Science:

• Polymer Science
• Materials Science
• Adhesion Science

Background:

• Pressure-sensitive adhesives (PSAs) with tunable tackiness are highly sought after.
• Switching adhesion without chemical additives or external agents remains a challenge.

Purpose of the Study:

• To investigate the potential of modifying bottlebrush network architecture using mild external stimuli.
• To induce tunable shifts in viscoelastic properties and adhesion of materials.

Main Methods:

• Incorporation of o-nitrobenzyl ester groups into cross-links of poly(n-butyl acrylate) brush networks.
• Controlled cleavage of cross-links using UV light to decrease network cross-link density.
• Quantitative analysis of shifts in plateau modulus and Rouse relaxation time.

Main Results:

• UV light exposure controllably reduced cross-link density.
• Achieved quantitatively predictable shifts in viscoelastic properties.
• Enhanced work of adhesion by over 3 orders of magnitude across a range of peel rates.
• Identified three distinct adhesion regimes based on deformation rate and cross-linking density.

Conclusions:

• Bottlebrush network architecture can be reversibly tuned via UV light to control adhesion.
• This method offers a pathway to switchable adhesion without additives.
• The findings have implications for designing advanced adhesives with tunable performance.