Organic material characteristics of volume change and stress generation have attracted the attention of many researchers aiming to develop chemomechanical systems such as artificial muscles and polymer engines having the advantages of high energy density and silent operation. Although polymer gels offer a relatively large actuator stroke, their mechanical properties are relatively poor and the ...

Fluorescence correlation spectroscopy (FCS) is a well-established technique for studying dynamic processes and interactions with minimal invasion into the corresponding system. Even though FCS has been mainly applied to biological systems, within the last 15 years an increasing number of studies in material sciences have appeared, demonstrating its enormous potential also for this field. Apart ...

We recently found that the energy contribution to linear elasticity of polymer gels in as-prepared state can be a significant negative value; shear modulus is not proportional absolute temperature [Y. Yoshikawa et al., Phys. Rev. X 11, 011045 (2021) (arXiv:1912.13191)]. Our finding challenges conventional notion polymer-gel mainly determined by entropy contribution. Existing molecular models cl...

A significantly soft and tough nanocomposite gel was realized by a novel network formed using cyclodextrin-based polyrotaxanes. Covalent bond formation between the cyclic components of polyrotaxanes and the surface of silica nanoparticles (15 nm diameter) resulted in an infinite network structure without direct bonds between the main chain polymer and the silica. Small-angle X-ray scattering re...

Diffusion in polymer solutions and gels has been studied by various techniques such as gravimetry, membrane permeation, fluorescence and radioactive labeling. These studies have led to a better knowledge on polymer morphology, transport phenomena, polymer melt and controlled release of drugs from polymer carriers. Various theoretical descriptions of the diffusion processes have been proposed. T...

We performed theoretical and computational studies to determine the effect of an applied mechanical strain on the dynamic behavior of heterogeneous polymer gels undergoing the oscillatory Belousov-Zhabotinsky (BZ) reaction. In these spatially heterogeneous gels, the catalyst for the reaction is localized in specific patches within the polymer network and the BZ reaction only occurs within these...

Polymer networks are widely used from commodity to biomedical materials. The space-spanning, net-like structure gives polymer networks their advantageous mechanical and dynamic properties, the most essential factor that governs their responses to external electrical, thermal, and chemical stimuli. Despite the ubiquity of applications and a century of active research on these materials, the way ...

From polymer gels to cytoskeletal structures, random networks of elastic material are commonly found in both materials science and biology. We present a three-dimensional micromechanical model of these networks and identify a "bending-to-stretching" transition. We characterize this transition in terms of concentration scaling laws, the stored elastic energy, and affinity measurements. Understan...

We discuss the main findings of a long-term research program exploring the consequences of sodium/calcium ion exchange on the macroscopic osmotic and elastic properties, and the microscopic structure of representative synthetic polyelectrolyte (sodium polyacrylate, (polyacrylic acid)) and biopolymer gels (DNA). A common feature of these gels is that above a threshold calcium ion concentration, ...

Abstract The wall slip and flow behavior of alginate as well gelatin based hydrogels with respect to the impact these rheological wetting properties on extrusion‐based bioprinting (EBB) was investigated. Capillary rheometry printing tests indicate that is negligible at high stresses relevant for EBB, i.e., above yield stress. On contrary, rotational performed low shear revealed present much str...