| AVS 66th International Symposium & Exhibition | |
| Chemical Analysis and Imaging Interfaces Focus Topic | Thursday Sessions |
| Session CA+NS+SS+VT-ThA |
| Session: | Progress in Instrumentation and Methods for Spectro-microscopy of Interfaces |
| Presenter: | Andrei Kolmakov, National Institute of Standards and Technology (NIST) |
| Authors: | T. Gupta, National Institute of Standards and Technology (NIST) P. Zeller, Elettra - Sincrotrone Trieste, Trieste, Italy M. Amati, Elettra - Sincrotrone Trieste, Trieste, Italy L. Gregoratti, Elettra - Sincrotrone Trieste, Trieste, Italy A. Kolmakov, National Institute of Standards and Technology (NIST) |
| Correspondent: | Click to Email |
Gels are porous polymeric scaffolds that can retain high volume fraction of liquids, can be easily functionalized for a specific need, can be made biocompatible and therefore, found numerous applications in drugs devilry, tissue engineering, soft robotics, sensorics, energy storage, etc. We have recently proposed a technique for micro-patterning and high-resolution additive fabrication of 3D gel structures in natural liquid solutions using electron and soft X-ray scanning microscopes [1]. The core of the technology is the employment of ultrathin electron (X-ray) transparent molecularly impermeable membranes that separate high vacuum of the microscopes from a high-pressure fluidic sample. In this communication, we report on effects of the beam and exposure conditions on to the degree of crosslinking of pristine and composite PEGDA hydrogels. We found that cross-linking occurs at very low irradiation doses. The size of the crosslinked area saturates with the dose and bond scission occurs at elevated radiation doses what has been supported with O 1s and C 1s XPS spectra evolution and prior research [2]. These chemically modified regions can be selectively etched what enables an additional partnering option for the gelated features with a spatial resolution of ca 20 nm. Finally, we defined the imaging conditions for guest particles in composite hydrogels in its liquid state during the crosslinking process. We were able to observe the electrophoretic migration of sub 100 nm Au nanoparticles inside the gel matrix.
References
[1] T. Gupta et al., "Focused Electron and X-ray Beam Crosslinking in Liquids for Nanoscale Hydrogels 3D Printing and Encapsulation," arXiv preprint arXiv:1904.01652, 2019.
[2] N. Meyerbröker and M. Zharnikov, "Modification and Patterning of Nanometer-Thin Poly (ethylene glycol) Films by Electron Irradiation," ACS applied materials & interfaces, vol. 5, no. 11, pp. 5129-5138, 2013.