Session: ASME Undergraduate Student Design Expo

Paper Number: 175868

Hydrogel Radiation-Shielding Viability Under the Influence of Microgravity 

This study aims to study polyvinyl alcohol (PVA) hydrogels’ structural stability and radioprotective properties in microgravity.  Hydrogels are three dimensional (3D) crosslinked polymer networks with widespread application in biomedical, drug delivery, and tissue engineering domains owing to their remarkable ability to retain massive water content with gel-like structure flexibility. Radiation exposure poses a significant challenge for long-term space missions since cosmic rays cause DNA damage and are carcinogenic to astronauts. These water-based materials have been proposed as possible radiation shielding materials to mitigate such effects due to their ability to stop high-energy radiation. They are able to hold large amounts of water in compact, non-flowing surface areas. Water is a great radiation shield due to its high density and its hydrogens, both of which allow water to slow down radiation particles. Having water in an organized construct like a hydrogel could allow for equal distribution of water, and therefore better protection against radiation. 

The study aims to test whether microgravity-induced aggregation affects the integrity of hydrogel networks, which could affect their ability to diffuse radiation effectively. A dehydrated hydrogel sample, along with a separate water reservoir, will be sent aboard the International Space Station (ISS), tentatively in April 2026. Upon reaching microgravity conditions, the water will be introduced to allow the hydrogel to swell and form its intended structure. Since hydrogels are colloidal suspensions stabilized by hydrogen bonding and polar interactions, microgravity could disrupt these forces, causing polymer aggregation. If aggregation occurs, the hydrogel's ability to function as an effective radiation shield may be diminished due to uneven polymer distribution. Once the experiment concludes, the samples will be returned to Earth for analysis. A separate sample of hydrogel will be rehydrated on Earth when the sample on the ISS is rehydrated. After the experiment concludes, this sample will be placed in a centrifuge to mimic the Gs experienced by the ISS sample on the return to Earth. Structural integrity of both sets of samples will be evaluated through dynamic light scanning (DLS), cryo-scanning electron microscopy, and mechanical tensile testing. DLS testing and cryo-scanning electron microscopy will be used to determine the size distribution and spatial arrangement of particles at the nanoscale. The tensile testing will be performed to determine any changes to the elastic/plastic regions of the hydrogel’s stress-strain diagrams, as changes to the material’s stress resistance could diminish the hydrogel’s abilities to mitigate radiation longterm.

Overall, this study aims to ascertain how well hydrogels absorb radiation after exposure to microgravity conditions. Two general approaches will be examined: (1) examining the structural and mechanical properties of hydrogels exposed to microgravity conditions and (2) testing the light scattering abilities of hydrogels exposed to microgravity conditions to test their viability to disperse radiation. Understanding these correlations will help provide a deeper understanding of hydrogels as materials that absorb radiation and help guide their optimization for future applications in healthcare, space technology, and protective coatings. It will also provide greater insight into the particle physics of colloid suspensions in microgravity for further research into hydrophilic colloid substances.

Presenting Author: Leighton Karpinia Florida Institute of Technology

Presenting Author Biography: Leighton Karpinia is a second year student at Florida Institute of Technology majoring in Mechanical Engineering, with a minor in Chemistry. He has organized a team of five to create the experiment being presented, which received funding to be performed on the International Space Station. He specializes in design and manufacturing within his major. When not working with mechanical engineering subject matter, Leighton likes to draw, read and birdwatch.

Authors:

Leighton Karpinia Florida Institute of Technology
Leyla Avant Florida Institute of Technology
Sampada Koirala Florida Institute of Technology
Emily Matheson Florida Institute of Technology
Caroline Moore Florida Institute of Technology