Rubber-to-glass adhesion between a rigid sphere and a shape memory polymer substrate of finite thickness

Changhong Linghu; Wentao Mao; Haoyu Jiang; Huajian Gao; K. Jimmy Hsia

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arXiv · 2411.17053

Rubber-to-glass adhesion between a rigid sphere and a shape memory polymer substrate of finite thickness

Changhong Linghu·Wentao Mao·Haoyu Jiang·Huajian Gao·K. Jimmy Hsia

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Abstract

Shape memory polymers (SMPs) are emerging as innovative smart adhesive materials with broad application potential. Compared to conventional elastomeric adhesives, SMP adhesives are distinguished by the so-called rubber-to-glass (R2G) adhesion, which involves contact in the rubbery state followed by detachment in the glassy state. This process, through a shape-locking effect, enhances adhesion strength by more than an order of magnitude compared to conventional adhesive contact. Here, we investigate the fundamental problem of a rigid sphere undergoing R2G adhesion with an SMP substrate of finite thickness through experiments, finite element (FE) simulations, and theoretical modeling. It is demonstrated that during press-in, the contact problem can be modeled as a rigid oblate spheroid contacting an infinite substrate, while the pull-off process can be described by a modified ball-and-socket model. These equivalent models yield practically useful analytical solutions for the contact radius during press-in and the R2G adhesion force during pull-off. A critical thickness-to-contact-radius ratio of around 5 is identified, below which the thickness effect becomes significant. These insights provide valuable guidance for the design and application of SMP-based smart adhesives.

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Changhong Linghu, Wentao Mao, Haoyu Jiang, Huajian Gao, K. Jimmy Hsia. 2024-11-26. Rubber-to-glass adhesion between a rigid sphere and a shape memory polymer substrate of finite thickness. https://arxiv.org/abs/2411.17053

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