Elasticity and Fracture of Gels, Elastomers, and Composites

Session Chairs

Michael Lang (Leibniz-Institute of Polymer Research, Dresden, Germany)

Sven Wießner (Leibniz-Institute of Polymer Research, Dresden, Germany)

Invited Speakers

Jose Augusto Berrocal (ICIQ, Spain)

From Small Molecules to Mechanoresponsive Networks: Triarylmethane Mechanophores in Action (Shared talk with Sensors, Actuators & Responsive Materials)

Understanding how small molecules respond to mechanical force is key to designing next-generation responsive materials. In this talk, I will present our recent work on triarylmethane-based mechanophores, focusing on their force-induced reactivity and integration into polymer networks. By linking molecular-scale insights to macroscopic behavior, we aim to develop mechanoresponsive polymers with tunable and predictable functionalities.

Costantino Creton (ESPCI Paris, France)

Experiments and molecular scale simulations on fracture of double networks elastomers

Stretchable double networks rely on network architecture and not on viscoelastic effects to display exceptional resistance to crack growth. It is often argued that the presence of sacrificial bonds acts as energy dissipators imparting the observed high toughness by slowing down crack propagation. Yet this does not explain toughening of hydrogels and recent experiments on elastomers point mainly at the role of the network architecture in delaying crack nucleation by forming a stable damage zone in front of a high stress region. We will present a multi-scale approach of experiments and molecular scale simulations to address the toughening mechanism of double network elastomers.

Andrey Dobrynin (UNC, USA)

Polymer Networks: From Design to Forensics

The ability to design polymer networks with programmable viscoelastic properties is vital for novel materials development for medical implants, tissue engineering, soft robotics, and wearable electronics. In this talk, I will demonstrate how to encode viscoelasticity of different soft materials in synthetic elastomers by varying molecular architecture of the network strands. The talk will end with an overview of AI applications to network design and forensic analysis of the network structure based on the network’s nonlinear deformations.

Jeremiah Johnson (Massachusetts Institute of Technology, USA)

Deconstructing Polymer Networks to Decode Their Structure (shared talk with Advanced Synthesis & New Architectures)

The properties of polymer networks are governed by their composition and topology across multiple length scales. Certain stochastic topological features of networks, including loops, remain challenging to measure and control. This talk will introduce Network Disassembly Spectrometry (NDS) as an experimental tool to measure cyclic and dangling end structures in polymer networks. A novel “time-dependent” NDS method will be introduced, which unveils new interactions between enzymes and topological features in hydrogels.

Tasuku Nakajima (Hokkaido Univ., Japan)

Polymer gels whose network strands are super-stretched

In conventional polymer gels, the network strands are typically coiled. Here, we report our discovery that polymer gels with network strands stretched nearly to their breaking point exhibit anomalous elasticity, fracture behavior, and functionality.

Michael Rubinstein (Duke, USA)

The Art of Network Design

We discuss several methods of designing polymer networks and gels and different ways of making these networks tougher, including using stored length and sacrificial bonds, slide rings, entanglements, and microphase separation. It turns out that whether weaker or stronger crosslinks lead to tougher networks depends on the placement of these crosslinks – either as parts of network strands or as connections between primary chains. The optimal strength of the sacrificial crosslinks and their concentration depends on the strength of the primary chain bonds. An interplay between main chain pull-out and bond cleavage depends on the deformation rate. A combination of these approaches in double networks utilizes double microphase separation on two different scales. All these methods lead to the narrowing of the tension distribution in network strands and, most importantly, the reduction of tension in the overstretched strands.

Takamasa Sakai (Univ. Tokyo, Japan)

Precision Gel Science: From Homogeneous to Heterogeneous Gels (shared talk with Hydrogels & Ionogels)

This talk introduces our efforts in establishing “Precision Gel Science” by fabricating structurally homogeneous polymer networks (TetraPEG gels) that allow direct, quantitative links between microscopic architecture and macroscopic properties. We highlight a universal scaling law for osmotic pressure as a tool to characterize network inhomogeneity, providing a new foundation for rational gel design across materials and applications.

Franck Vernerey (U. Colorado, USA)

Molecular damage of polymer networks Chain rupture versus Cavitation

Polymer networks under stress can fail through two competing mechanisms: chain rupture or cavitation, the nucleation of voids within the material. This presentation will discuss how the dominant failure mode depends critically on the stress state (especially the level of triaxiality) and the rate of loading, which control whether the network breaks or voids form. It will also highlight how the architecture of the network, from permanent covalent links to reversible dynamic bonds, mediates this competition and offers new strategies to control toughness and failure.

Contributed talks and posters

... will be continuously added until the abstract acceptance deadline.