Peeling-Induced Rolling and Heterogeneous Adhesion in Blistered Films

TL;DR

Blisters in multilayer films under compression trigger an unusual interfacial dynamics during peeling, where the advancing front causes simultaneous detachment at the peel edge and reattachment at the blister edge, initiating a roll of the film. The study combines experiments, coarse-grained molecular dynamics simulations, and scaling analysis to identify a finite rolling contact length $\ell_c^r$ and a discontinuous adhesion-force drop $\Delta F$, governed by a decay length $\ell$ and a dynamically imposed dwell time $t_r=\ell_c^r/V$. The onset length scales as $\ell \sim (B/E_a)^{1/6} h_a^{1/2}$ and is largely independent of the work of adhesion, while $t_r$ sets how aging and viscoelastic dissipation shape the post-transition adhesion, linking contact history to force. The results show how blister geometry can be used to engineer spatially heterogeneous adhesion on otherwise homogeneous interfaces, offering a framework for programmable adhesion in thin-film systems and reconfigurable surface design.

Abstract

Blisters, delaminated regions that form in multilayered structures under compressive stresses, are observed across a wide range of length scales, from two-dimensional materials to protective coatings and laminated composites. Far from being passive defects, such interfacial features have emerged as functional motifs for three-dimensional architectures and reconfigurable surfaces. Here we reveal an unusual peel response of a blistered thin film on a soft substrate. When peeled from one end, the advancing peel front triggers reattachment at the blister edge once a critical separation is reached, initiating spontaneous rolling of the film on the substrate. This peel-to-roll transition produces a sharp drop in the measured adhesion force, which then remains constant throughout the rolling phase. Using experiments, scaling analysis, and molecular dynamics simulations, we resolve the contact morphology at the transition and identify the contact length at which rolling initiates. We show that this length arises from interactions between the two contact edges and is independent of the work of adhesion. Once rolling begins, a dynamically imposed dwell time - defined by the rolling length and peel speed - translates contact history into spatial variations in adhesion force, thereby governing the magnitude of the force drop. Together, these results point to a new pathway for generating spatially tunable, heterogeneous adhesion from otherwise homogeneous interfaces.

Figures (5)

• Figure 1: Peel-to-roll transition and the associated force drop during peeling of sticky blisters. a. Schematic of a thin Mylar film adhered to a soft silicone elastomer and peeled at a 90$^{\circ}$ angle. As the peel front approaches the blister edge, the contact length $\ell_c$ decreases. Inset: Magnified contact zone showing asymmetric substrate deformation and film curvature. b. Force–displacement curve exhibiting two regimes: steady-state peeling followed by a sudden force drop ($\sim$ 260%) during rolling. Notably, the drop in force lags behind the onset of rolling. This data corresponds to 25 $\mu$m thick Mylar and 12 mm thick substrate. c. Composite time-lapse image showing the evolution of the blister during rolling. Color gradient from light to dark tracks the progression in time. Arrows mark simultaneous detachment and reattachment, defining a stable rolling contact length $\ell_c^r$. d. Molecular dynamics simulations reproduce the peel-to-roll transition; snapshots are shown for every 1.8 mm of peel displacement. Yellow indicates the film, pink the substrate interior, and blue the substrate surface. e. Robustness across commercial adhesives: (i) Scotch 3M 600 tape on acrylic, (ii) Velcro peeled from itself, and (iii) a blistered mylar sheet peeled from 3M VHB acrylic foam adhesive.
• Figure 2: Contact morphology and delayed force response during the peel‑to‑roll transition.a. Evolution of contact length $\ell_c$ as the film is peeled. $\ell_c$ decreases steadily during classical peeling until the onset of rolling, at which point it stabilizes at a constant value $\ell_c^r$. b. Adhesion force measured simultaneously shows a delayed response: force remains at the peel value at the onset of rolling, and only drops after an additional $\simeq 10$ mm of peel displacement. c. Substrate deformation at the peel edge, $u_p$, mirrors the force response: it remains large during peeling and decreases sharply once rolling is fully established. These data corresponds to 50 $\mu$m mylar film being peeled from 3.5 mm thick substrate at 0.17 mm/s.
• Figure 3: Curvature evolution within the adhesive contact. The film curvature $\kappa(x)$ along the adhered region evolves as the contact length $\ell_c$ decreases from the peel phase (yellow) to the onset of rolling (black).The peel front is stationary at $x=0$ (orange square), while blister edge positions at successive times are marked by circles. Inset: $\kappa"$ provides an estimate of the normal traction transmitted to the substrate within the contact. The tensile region at the blister edge disappears at the rolling onset, consistent with the loss of a distinct curvature boundary condition there.
• Figure 4: Contact length at rolling onset. a. Contact length at the rolling onset are plotted as a function of adhesive thickness ($h_a$). Marker shape denotes film material (Mylar, FEP, PET, PFA), marker size increases with bending modulus $B$, and color gradient from dark to light indicates increasing adhesive thickness. The solid line $\ell_c^r = h_a$ separates the thin-adhesive ($h_a \ll \ell_c^r$) and thick-adhesive ($h_a \gg \ell_c^r$) regimes. Numerical data points corresponds to a 50 $\mu$m thick film with elastic modulus 1 GPa adhered to a soft substrate with modulus 10 kPa. b. $\ell_c^r$ plotted against the predicted decay length $\ell$ computed from Eq. \ref{['eq3']} for data in the thin-adhesive regime ($h_a < \ell_c^r$). The dashed line represents a fit to the collapsed data, yielding $\ell_c^r\simeq3.0\ell$.
• Figure 5: Force jump at the peel-to-roll transition and multi-step, heterogeneous adhesion landscape in blister arraya. Dimensionless force drop at the transition, ($\Delta F/\Delta F_m$), plotted against the ratio of dwell times in the roll ($\ell_c^r/V$) and peel ($t_w$) phases. Data points correspond to measurements conducted at various peel speeds ($V$), peel phase contact times ($t_w$), and $\ell_c^r$ values. The dashed line represents a power-law with exponent matching the elastomer’s rheological exponent $n=0.55$. For $\ell_c^r/(V t_w)>1$, the contact time during rolling exceeds the initial contact age and interfacial aging begins to dominate over bulk viscoelastic dissipation. b. An array of three blisters are placed following the sequence shown on the image, giving rise to the sequence of peel phase contact ages $t_w^1>t_w^2>t_w^3$. The peel front propagates from left to right. c. Measured force–displacement curve for peeling across the blister array in panel (b). Each blister produces a distinct peel-to-roll transition, resulting in a multistep, heterogeneous adhesion landscape. The magnitude of each force drop is set by the corresponding dwell-time ratio $t_r/t_w$, enabling tunable and sequential adhesion responses in an otherwise homogeneous interface.