Solvotaxis: Gel Motion Against Gravity via Autonomous Solvent Exchange
6 affiliations
- 1Department of Chemistry and Biochemistry
- 2Center for Discovery and Innovation, The City College of New York, CUNY
- 3Ph.D. Program in Chemistry, Graduate Center of the City University of New York, 365 Fifth Ave, New York, NY, USA, 10016
- 4Faculty of Science, University of South Bohemia, Branisovska 1760, Ceske Budejovice, Czech Republic, 370 05
- 5Department of Chemical & Biomolecular Engineering
- 6University of Maryland
Abstract
Molecular gelation, where a low-molecular-weight gelator (LMWG) self-assembles into a network of fibers, has long obeyed a simple rule: a solvent can be gelled only if the gelator is at least partially soluble in it. In this work, we overturn this paradigm and show that the disaccharidebased gelator 4′,6′-O-benzylidene amygdalin (BA) forms stable gels in solvents where it is completely insoluble. BA dissolves in aqueous media upon heating and forms hydrogels upon cooling, but it is insoluble and does not form gels in oils. When an immiscible nonpolar oil is placed atop a BA hydrogel, the network spontaneously absorbs the oil, expels the water, and migrates upward against gravity. At steady state, a stable BA organogel sits atop liquid water. We refer to this process as Autonomous Solvent Exchange (ASE) and it reveals a strong preference of BA fibers for oil over water (whereas BA molecules prefer water). ASE thus leads to the unusual phenomenon of solvotaxis, i.e., migration of the gel toward its preferred solvent without disrupting the fibrous network. BA organogels with tunable strengths can be formed by solvotaxis across a range of oils (e.g., n-alkanes, natural oils, fuels). Overall, by decoupling molecular solubility from gelation, solvotaxis expands the landscape of gelation to previously inaccessible liquids. Our work also establishes new principles for designing materials that respond autonomously to chemical gradients, with potential applications in environmental remediation and oil recovery.
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BibTeX
@misc{kuruva2026solvotaxis,
title = {{Solvotaxis: Gel Motion Against Gravity via Autonomous Solvent Exchange}},
author = {Pruthvi Kuruva and Arun K. Rachamalla and Gowtham N. Jonnalagadda and William Blodgett and Zdenek Futera and Srinivasa R. Raghavan and George John and GEORGE JOHN},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010678/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010678/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Solvotaxis: Gel Motion Against Gravity via Autonomous Solvent Exchange
AU - Pruthvi Kuruva
AU - Arun K. Rachamalla
AU - Gowtham N. Jonnalagadda
AU - William Blodgett
AU - Zdenek Futera
AU - Srinivasa R. Raghavan
AU - George John
AU - GEORGE JOHN
PY - 2026
DA - 2026/10/19
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010678/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010678/v1
AB - Molecular gelation, where a low-molecular-weight gelator (LMWG) self-assembles into a network of fibers, has long obeyed a simple rule: a solvent can be gelled only if the gelator is at least partially soluble in it. In this work, we overturn this paradigm and show that the disaccharidebased gelator 4′,6′-O-benzylidene amygdalin (BA) forms stable gels in solvents where it is completely insoluble. BA dissolves in aqueous media upon heating and forms hydrogels upon cooling, but it is insoluble and does not form gels in oils. When an immiscible nonpolar oil is placed atop a BA hydrogel, the network spontaneously absorbs the oil, expels the water, and migrates upward against gravity. At steady state, a stable BA organogel sits atop liquid water. We refer to this process as Autonomous Solvent Exchange (ASE) and it reveals a strong preference of BA fibers for oil over water (whereas BA molecules prefer water). ASE thus leads to the unusual phenomenon of solvotaxis, i.e., migration of the gel toward its preferred solvent without disrupting the fibrous network. BA organogels with tunable strengths can be formed by solvotaxis across a range of oils (e.g., n-alkanes, natural oils, fuels). Overall, by decoupling molecular solubility from gelation, solvotaxis expands the landscape of gelation to previously inaccessible liquids. Our work also establishes new principles for designing materials that respond autonomously to chemical gradients, with potential applications in environmental remediation and oil recovery.
ER -