arXiv subjects

Nolan A. Miller

Publications and source records attributed to Nolan A. Miller.

3 recordsLinked to original sources

arXiv2026

Supercritical Snapping and Controlled Launching via Dual Latch Gels

Natural organisms have evolved integrated Latch-Mediated Spring Actuation systems (LaMSA) that consist of multiple latches and springs to enhance power output and adapt to diverse environmental conditions. Similar designs are appealing yet largely unexplored in engineered materials due to the complexity of integrating multiple components into a single material platform. Here, we report a dual-latched magneto-elastic shell device capable of selectively activating the latches to regulate snapping pathways and energy output based on specific actuation requirements. Differential deswelling across the thickness acts as the motor to load the elastic energy into the shell, which is then released via the snap-through instability once the loading reaches the critical threshold, constituting an intrinsic mechanical latch. Activation of the external magnetic latch delays snapping onset beyond the threshold of the intrinsic latch, leading to a power-amplified supercritical snap-through instability as well as a bifurcation instability. The combined function of both latches allows for flexible control over energy storage and release. Additionally, this integrated LaMSA system possesses an untethered anchoring mechanism, enabling the device to launch in arbitrary directions from the substrate, driven by the energy released during snapping. We envision that the design principles of dual-latched LaMSA systems will create opportunities for power-dense actuation in engineered materials and robotic devices.

physics.app-ph↗

arXiv2026

Modulus and confinement effects on self-repeating, power-amplified snapping of soft, swollen beams

Latch-mediated Spring Actuation (LaMSA) is a mechanism found in nature, employed by organisms that generate the highest levels of power density through repeatable, rapid energy release. While LaMSA has been used in engineered systems like archery bows, catapults, and jumping robots, most such technologies require external power for self-repeating motion. Recent advances in soft actuators have demonstrated that engineered gels swollen with a volatile solvent are capable of self-repeating, high specific-power generation by taking advantage of balances between environmental interaction (evaporation) and elasticity. These systems rely upon snap-through instabilities. Due to the complex coupling between material properties and geometry, both of which evolve as self-repeating motion continues, an understanding of how polymer properties and boundary conditions control the lifetime, count, and magnitude of power generating events for a given amount of solvent remains unrealized. We overcome the challenges in characterizing the performance of evaporation-driven, power-generating gels by measuring accumulating force response from evaporation in parallel with the profile deformation of the structure. By optimizing the balance between swelling properties and elasticity, the lifetime of snapping is increased by 445% from previous literature, snapping at a maximum power density of about 87 W/kg. This power is achieved with swollen beams 50 mm in length after 53 mg of solvent had evaporated and is comparable to the power output of adult jumping mantises at 68 W/kg at a similar size scale.1 We develop scaling relationships that balance Flory-Rehner swelling theory with buckling mechanics to generate insight into optimizing lifetime and power of autonomous power-generating systems.

cond-mat.soft↗

arXiv2025

Poroelasticity of bottlebrush and linear polymer networks

The transport of solvent molecules through soft, swollen networks is critical in both natural and engineered systems. While this poroelastic flow has traditionally been explored in networks where the mesh size is comparable to the solvent molecule size, the effect of network architecture on permeability remains underexplored. Here we investigate solvent transport in linear polymer networks (LPN) and highly elastic bottlebrush elastomer networks (BBN), where the presence of densely grafted sidechains allows for control over swelling and mechanical properties. By synthesizing BBNs with systematically varied crosslinking density while maintaining constant sidechain length and grafting density, we probe the poroelastic response in the stretched backbone regime (SBB). Poroelastic relaxation indentation experiments, performed in toluene, reveal how permeability scales with crosslink density and polymer volume fraction. Compared to LPN with identical chemistry, the BBN exhibited a lower permeability scaling exponent with polymer volume fraction that closely matches the theoretical exponent. Despite architectural differences, permeability data for both networks collapse onto a single curve when plotted against dry shear modulus. Our findings demonstrate that molecular network architecture significantly influences permeability, offering new routes to tailor solvent transport in soft, swollen networks. These insights highlight BBNs as a promising platform for applications in permeable membranes, filtration, and microfluidic systems, and pave the way for further studies on how network parameters, such as sidechain length, impact permeability in these highly tunable materials.

cond-mat.soft↗