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192 results on '"Eisenbach, Claus D."'

2. Data-Driven Framework for the Prediction of PEGDA Hydrogel Mechanics

Author

Tang, Yongkui, Levin, Michal, Long, Olivia G., Eisenbach, Claus D., Cohen, Noy, and Valentine, Megan T.

Abstract

Poly(ethylene glycol) diacrylate (PEGDA) hydrogels are biocompatible and photo-cross-linkable, with accessible values of elastic modulus ranging from kPa to MPa, leading to their wide use in biomedical and soft material applications. However, PEGDA gels possess complex microstructures, limiting the use of standard polymer theories to describe them. As a result, we lack a foundational understanding of how to relate their composition, processing, and mechanical properties. To address this need, we use a data-driven approach to develop an empirical predictive framework based on high-quality data obtained from uniaxial compression tests and validated using prior data found in the literature. The developed framework accurately predicts the hydrogel shear modulus and the strain-stiffening coefficient using only synthesis parameters, such as the molecular weight and initial concentration of PEGDA, as inputs. These results provide simple and reliable experimental guidelines for precisely controlling both the low-strain and high-strain mechanical responses of PEGDA hydrogels, thereby facilitating their design for various applications.

Published
2025
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3. Toughening elastomers using mussel-inspired iron-catechol complexes.

Author

Filippidi, Emmanouela, Cristiani, Thomas R, Eisenbach, Claus D, Waite, J Herbert, Israelachvili, Jacob N, Ahn, B Kollbe, and Valentine, Megan T

Subjects
General Science & Technology
Abstract

Materials often exhibit a trade-off between stiffness and extensibility; for example, strengthening elastomers by increasing their cross-link density leads to embrittlement and decreased toughness. Inspired by cuticles of marine mussel byssi, we circumvent this inherent trade-off by incorporating sacrificial, reversible iron-catechol cross-links into a dry, loosely cross-linked epoxy network. The iron-containing network exhibits two to three orders of magnitude increases in stiffness, tensile strength, and tensile toughness compared to its iron-free precursor while gaining recoverable hysteretic energy dissipation and maintaining its original extensibility. Compared to previous realizations of this chemistry in hydrogels, the dry nature of the network enables larger property enhancement owing to the cooperative effects of both the increased cross-link density given by the reversible iron-catecholate complexes and the chain-restricting ionomeric nanodomains that they form.

Published
2017

4. Microphase Behavior and Enhanced Wet-Cohesion of Synthetic Copolyampholytes Inspired by a Mussel Foot Protein

Author

Seo, Sungbaek, Das, Saurabh, Zalicki, Piotr J, Mirshafian, Razieh, Eisenbach, Claus D, Israelachvili, Jacob N, Waite, J Herbert, and Ahn, B Kollbe

Subjects
Biotechnology, Adhesiveness, Amino Acid Sequence, Animals, Biomimetic Materials, Bivalvia, Electrochemistry, Molecular Sequence Data, Polymethyl Methacrylate, Proteins, Surface Properties, Chemical Sciences, General Chemistry
Abstract

Numerous attempts have been made to translate mussel adhesion to diverse synthetic platforms. However, the translation remains largely limited to the Dopa (3,4-dihydroxyphenylalanine) or catechol functionality, which continues to raise concerns about Dopa's inherent susceptibility to oxidation. Mussels have evolved adaptations to stabilize Dopa against oxidation. For example, in mussel foot protein 3 slow (mfp-3s, one of two electrophoretically distinct interfacial adhesive proteins in mussel plaques), the high proportion of hydrophobic amino acid residues in the flanking sequence around Dopa increases Dopa's oxidation potential. In this study, copolyampholytes, which combine the catechol functionality with amphiphilic and ionic features of mfp-3s, were synthesized and formulated as coacervates for adhesive deposition on surfaces. The ratio of hydrophilic/hydrophobic as well as cationic/anionic units was varied in order to enhance coacervate formation and wet adhesion properties. Aqueous solutions of two of the four mfp-3s-inspired copolymers showed coacervate-like spherical microdroplets (ϕ ≈ 1-5 μm at pH ∼4 (salt concentration ∼15 mM). The mfp-3s-mimetic copolymer was stable to oxidation, formed coacervates that spread evenly over mica, and strongly bonded to mica surfaces (pull-off strength: ∼17.0 mJ/m(2)). Increasing pH to 7 after coacervate deposition at pH 4 doubled the bonding strength to ∼32.9 mJ/m(2) without oxidative cross-linking and is about 9 times higher than native mfp-3s cohesion. This study expands the scope of translating mussel adhesion from simple Dopa-functionalization to mimicking the context of the local environment around Dopa.

Published
2015

8. New Polyelectrolyte Architectures

Author

Bohrisch, Jörg, Eisenbach, Claus D., Jaeger, Werner, Mori, Hideharu, Müller, Axel H. E., Rehahn, Matthias, Schaller, Christian, Traser, Steffen, Wittmeyer, Patrick, and Schmidt, Manfred, editor

Published
2004
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16. THE FUTURE OF APPLIED POLYMER SCIENCE

Author

JAFFE, MICHAEL, primary, Baer, Eric, additional, Dickie, Ray A., additional, Eisenbach, Claus D., additional, Frechet, Jean M.J., additional, Kennedy, J.P., additional, Koenig, J.L., additional, Kohn, Joachim, additional, Tirrell, David A., additional, Ward, Ian M., additional, Willson, C. Grant, additional, and Windle, Alan H., additional

Published
2000
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21. Aggregation behavior of rodlike ionogenic polymers in chloroform

Author

Susoff, Markus, Winter, Dominik, Eisenbach, Claus D., and Oppermann, Wilhelm

Subjects
Pyridine -- Structure, Pyridine -- Electric properties, Pyridine -- Optical properties, Light scattering -- Analysis, Water-soluble polymers -- Structure, Water-soluble polymers -- Electric properties, Water-soluble polymers -- Optical properties, Ultraviolet radiation -- Analysis, Chemicals, plastics and rubber industries
Abstract

The rigid rodlike and ionogenic polymers poly(p-pyridylene-phenylene) (PPPyP) and poly(p-pyridylene/phenylene-ethynylene) (PPPyPE) are examined in chloroform. Electric birefringence and light scattering are used for studying the dependence of the aggregation behavior of the polyelectrolytes on the degree of protonation and the concentration of different monovalent salts.

Published
2008

24. Molecular Mechanics of Beta-Sheets

Author

Cohen, Noy and Eisenbach, Claus D.

Abstract

β-Sheet protein structures and domains are widely found in biological materials such as silk. These assemblies play a major role in the extraordinary strength and unique properties of biomaterials. At the molecular level, the single β-sheet structure comprises polypeptide chains in zig-zag conformations that are held together by hydrogen bonds. β-sheet domains comprise multiple β-sheets that originate from hydrophobic interactions between sheets and are held together by van der Waals interactions. In this work, we introduce molecular models that capture the response of such domains upon mechanical loading and illustrate the mechanisms behind their collapse. We begin by modeling the force that is required to pull a chain out of a β-sheet. Next, we employ these models to study the behavior of β-sheets that are embedded into and connected to an amorphous protein matrix. We show that the collapse of a β-sheet occurs upon the application of a sufficiently high force that is transferred from the chains in the matrix to individual chains of the β-sheet structure and causes shear. With the aim of understanding the response of β-sheet domains, we derive models for the interactions between β-sheets. These enable the study of critical forces required to break such domains. As opposed to molecular dynamics simulations, the analysis in this work yields simple expressions that shed light on the relations between the nanostructure of β-sheet domains and their mechanical response. In addition, the findings of this work suggest how β-sheet domains can be strengthened.

Published
2024
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25. Structure of adsorption layers of amphiphilic copolymers on inorganic or organic particle surfaces

Author

Bulychev, Nikolay, Dervaux, Bart, Dimberger, Klaus, Zubov, Vitali, Du Prez, Filip, and Eisenbach, Claus D

Subjects
Chemistry, polymer gel layer, electrokinetic sonic amplitude method, DILUTE SUSPENSION, DYNAMIC MOBILITY, dispersions, SOLID-LIQUID INTERFACE [KeyWords Plus], block and block-like copolymers [Author Keywords], POLYMER, surfaces, pigment surface modification
Abstract

The structure of adsorption layers of amphiphilic block and block-like copolymers of poly(isobornyl acrylate) and poly(acrylic acid) on the surface of hydrophilic titanium dioxide and hydrophobic copper phthalocyanine (CuPc) pigments in an aqueous studied by the electrokinetic sonic amplitude (ESA) method. The electroacoustic behaviour of the polyelectrolyte block copolymer-coated particles could be described in the context of the polymer gel layer theory. The polymer layer around the particles was found to be much thinner for CuPc as compared to the TiO2 substrate. This is attributed to differences in the adsorption mechanism and the composition of the adsorption layer normal to the substrate surface. Adsorption models were established that consider effects of the copolymer structure.

Published
2010

27. New Polyelectrolyte Architectures

Author

Bohrisch, Jörg, primary, Eisenbach, Claus D., additional, Jaeger, Werner, additional, Mori, Hideharu, additional, Müller, Axel H. E., additional, Rehahn, Matthias, additional, Schaller, Christian, additional, Traser, Steffen, additional, and Wittmeyer, Patrick, additional

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