NanoRacks-Valley Christian High School of Dublin-Polyvinyl Alcohol Thin Film Experiment (NanoRacks-VCHSD-Polyvinyl Alcohol) - 11.22.16

Overview | Description | Applications | Operations | Results | Publications | Imagery

ISS Science for Everyone

Science Objectives for Everyone
Polyvinyl alcohol is a common chemical that forms a biodegradable film, which is used in eye drops, textiles and many other applications. NanoRacks-Valley Christian High School of Dublin-Polyvinyl Alcohol Thin Film Formation Experiment (NanoRacks-VCHSD-Polyvinyl Alcohol) studies how this chemical evaporates and whether thin films form on flat surfaces in microgravity as on Earth. Results improve understanding of the microgravity behavior of a widely used chemical, as well as microgravity’s effects on fluid dynamics, surface tension and evaporation.
Science Results for Everyone
Information Pending

The following content was provided by James Johnson, Ph.D., and is maintained in a database by the ISS Program Science Office.
Experiment Details

OpNom:

Principal Investigator(s)
Valley Christian High School of Dublin , Valley Christian High School of Dublin, Dublin, CA, United States

Co-Investigator(s)/Collaborator(s)
Angela Bruggeman, B.A., Dean of Academics, Valley Christian High School of Dublin, Dublin, CA, United States
James Johnson, Ph.D., Valley Christian High School, Dublin, CA, United States
Seyed Saatchi, B.S., Electrical Engineering, Valley Christian High School of Dublin, Dublin, CA, United States
Rick Vann, Valley Christian High School of Dublin, Dublin, CA, United States
Steven Brow, Valley Christian High School of Dublin, Dublin, CA, United States
Chris Montgomery, B.A., Faculty Director, Valley Christian High School of Dublin, Dublin, CA, United States

Developer(s)
Valley Christian High School , San Jose , CA, United States
NanoRacks LLC, Webster, TX, United States

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
National Laboratory Education (NLE)

Research Benefits
Earth Benefits, Scientific Discovery, Space Exploration

ISS Expedition Duration
March 2016 - September 2016

Expeditions Assigned
47/48

Previous Missions
Information Pending

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Experiment Description

Research Overview

  • Polyvinyl alcohol, which forms a biodegradable film, has biomedical applications; additionally, it is more commonly used in products such as dissolvable laundry bags.
  • Conducting NanoRacks-Valley Christian High School of Dublin-Polyvinyl Alcohol Thin Film Formation Experiment (NanoRacks-VCHSD-Polyvinyl Alcohol) aboard the International Space Station provides insight into the process with the potential to produce a better film.
  • The experiment uncovers new information regarding fluid dynamics as two pumps work together to drain a chamber of polyvinyl alcohol.
  • The experiment confirms past studies regarding surface tension and adhesion.
  • The experiment confirms past studies comparing evaporation rates in microgravity and in Earth gravity.

Description

NanoRacks-Valley Christian High School of Dublin-Polyvinyl Alcohol Thin Film Formation Experiment (NanoRacks-VCHSD-Polyvinyl Alcohol) examines how liquids behave when acted upon by pumps in microgravity. Layers of polyvinyl alcohol (PVOH) are dried on the walls of a polycarbonate chamber. Prior to flight, a drop of fluorescent dye (disodium fluorescein) was added to the solution so that UV and white LEDs illuminate the material as it is drained and then dried. Data is collected during film formation, and any film formed in microgravity is expected to have greater structural integrity due to enhanced phase interactions.
 
First, a full chamber of PVOH is drained using a peristaltic pump (RP-Q1 from Takasago Fluidics), with a second pump pushing air into the chamber to equalize pressure, leaving a residual layer of the substance on the chamber walls due to intermolecular forces. Next, air is cycled through the chamber and through a chamber containing silica gel for drying. A comparison of voltage across the film in space and on earth provides the means to compare evaporation rate.
 
There are no strict temperature requirements. Continuous power is needed for a minimum of two days after the first 28 duration hours of intermittent power. Thereafter power can be momentarily interrupted without significant disruption to the experiment. This experiment is designed to function for the duration of the flight onboard the International Space Station.
 
The final film is then brought back to Earth and peeled off of the flat polycarbonate inner surface of the chamber, after which it is examined under a scanning electron microscope for porosity (which should be lower than the film formed in the control experiment).

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Applications

Space Applications
Microgravity changes the behavior of fluids, including how they flow and evaporate. This investigation studies the evaporation of a common chemical called polyvinyl alcohol, determining whether a thin film forms on flat surfaces as the liquid evaporates, as it would under Earth gravity conditions. Results improve understanding of microgravity’s effects on this chemical and on fluid dynamics in general.

Earth Applications
Students in 8th through 12th grades at Valley Christian High School of Dublin designed this investigation, gaining experience and training in science, technology, engineering and math (STEM) concepts. The students worked with teachers and industry mentors to design, prototype and build an experiment to fly on the International Space Station, connecting them to the space program in a unique way.

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Operations

Operational Requirements and Protocols

NanoRacks Module-18 is completely autonomous and only requires installation and removal. During actual operation, data, photographic and other, is sent to the investigators to track the progress of the experiment. Data is transmitted intermittently throughout the duration of the module’s stay aboard the International Space Station (ISS). The payload chamber needs to be returned to the researches so its contents can be examined under an atomic force microscope.
 
Crew interaction with Module-18 is limited to transferring the NanoRacks locker insert from the launch vehicle to the ISS, installation and activation of the NanoRacks Frames into the EXPRESS Rack Locker, cleaning of the air inlet filter (as needed), and data retrieval (as needed) during the mission.

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Decadal Survey Recommendations

Information Pending

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Results/More Information

Information Pending

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Related Websites

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Imagery

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CAD diagram of experimental layout for NanoRacks-Valley Christian High School of Dublin-Polyvinyl Alcohol Thin Film Formation Experiment (NanoRacks-VCHSD-Polyvinyl Alcohol). Image courtesy of Valley Christian High School of Dublin, CA.

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Electrical system schematics for NanoRacks-Valley Christian High School of Dublin-Polyvinyl Alcohol Thin Film Formation Experiment (NanoRacks-VCHSD-Polyvinyl Alcohol). Image courtesy of Valley Christian High School of Dublin, CA.

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Electrical block diagram for NanoRacks-Valley Christian High School of Dublin-Polyvinyl Alcohol Thin Film Formation Experiment (NanoRacks-VCHSD-Polyvinyl Alcohol). Image courtesy of Valley Christian High School of Dublin, CA.

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Experimental chambers and pump connection for NanoRacks-Valley Christian High School of Dublin-Polyvinyl Alcohol Thin Film Formation Experiment (NanoRacks-VCHSD-Polyvinyl Alcohol), penny included for scale. Image courtesy of Valley Christian High School of Dublin, CA.

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