Anisotropic hygro-expansion in hydrogel fibers owing to uniting 3D electrowriting and supramolecular polymer assembly

Dan Jing Wu, Niels H. Vonk, Brigitte A.G. Lamers, Miguel Castilho, Jos Malda, Johan P.M. Hoefnagels, Patricia Y.W. Dankers (Corresponding author)

Research output: Contribution to journalArticleAcademicpeer-review

13 Citations (Scopus)


Melt electrowriting (MEW) is mostly applied to print complex three-dimensional (3D) structures using traditional, relatively hydrophobic polymers, such as polycaprolactone. Here, we 3D printed a supramolecular hydrophilic polymer into a solid micrometer-sized fiber structure, solely held together via non-covalent interactions. Interestingly, the solid fibers showed anisotropic swelling in a humid environment as demonstrated by the longitudinal and transverse surface strain determined using a novel global digital height correlation algorithm. This anisotropy in swelling is proposed to originate from a shear-induced orientation of crystals packed into lamellae as shown with small-angle x-ray scattering measurements. The MEW fibers were dried after swelling to study structural differences. Remarkably, no differences in nano-structural conformation in the micrometer-sized fibers was observed after swelling and subsequent drying. In conclusion, a free-standing supramolecular polymer-based hydrogel scaffold, displaying anisotropic hygro-expansion, is shown to be produced using MEW. This unique combination of 3D printing, via a top-down approach, and supramolecular polymer chemistry, via a bottom-up approach, provides new ways to introduce anisotropy and hierarchy in aqueous supramolecular systems. This will open the door towards even more complex hierarchical structures with unprecedented properties.

Original languageEnglish
Article number110099
Number of pages8
JournalEuropean Polymer Journal
Publication statusPublished - 5 Dec 2020


The authors thank A.F. Mason and G. Vantomme for useful discussions on the results and the ICMS Animation Studio for careful design of the schematic representations. In addition, M. Castilho thanks the strategic alliance between University Medical Center Utrecht and Eindhoven University of Technology. This work was financially supported by the Ministry of Education, Culture and Science (Gravity programs 024.001.035 and 024.003.013).

FundersFunder number
Universitair Medisch Centrum Utrecht
Eindhoven University of Technology
Ministerie van Onderwijs, Cultuur en Wetenschap024.003.013, 024.001.035


    • Additive manufacturing
    • Hydrogel
    • Hygro-expansion
    • Melt electrowriting
    • Supramolecular polymer


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