Increment 45 - 46 Science Symposium presentation of Advanced Colloids Experiment (ACE-T1) to RPO. The purpose of this event is for Principal Investigators to present their science objectives, testing approach, and measurement methods to agency scientists, managers, and other investigators

Brown, Dan

Eustace, John

Meyer, William V.

Sicker, Ron

NASA Technical Reports Server

National Aeronautics and Space Administration
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Presented by:
Dr. William V. Meyer (a.k.a. Bill Meyer)
ACE NASA Project Scientist
USRA at  NASA GRC, Tel: (216) 433-5011, Email: William.V.Meyer@NASA.Gov
ACE NASA Project Manager:  Ron Sicker, Tel.:  (216) 433-6498
ZIN-Technologies Project Lead: Dan Brown, Tel:  (440) 625-2219
ZIN-Technologies Science Lead: John Eustace, Tel:  (440) 625-2244
July 15, 2015
Increment 45/46 Science Symposium
Advanced Colloids Experiment (ACE-T1)
https://ntrs.nasa.gov/search.jsp?R=20150021274 2019-08-31T05:54:07+00:00Z
ACE-T1 science team
Prof. Chang-Soo Lee 
Department of Chemical Engineering 
Chungnam National University (CNU) 
South Korea
Group members involved in this project
• Chang-Hyung Choi
• Jae-Min Jung
• So-Young Han
Prof. Chang-Soo Lee
[S. KoreanTeam:  CNU]
PI / Provide flight samples, 
science requirements, and data analysis
Professor of Chemical Eng., Department of Chemical Engineering
School of Engineering, 1-258
Chungnam National University, Daejeon, Korea
Tel: 82-42-821-5896; rhadum@cnu.ac.kr
ACE-T1 is a NASA collaboration with Professsor Chang-Soo Lee at Chungnam University (CNU), South 
Korea, resulting from a June 2009 U.S. - Korean summit and report “Joint Vision for the Alliance of the 
United States of America and the Republic of Korea”.
ISS Increments 45 and 46 Science Symposium 
Advanced Colloids Experiment 
(Temperature controlled) – ACE-T1
• Science Background and Hypothesis 
• Investigation goals and objectives
• Measurement approach
• Importance and reason for ISS
• Expected results and how they will 
advance the field 
• Earth benefits/spin-off applications
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• Project explores 3D self-assembly of complex (Janus, multi-sided) particles that are hydrophobic and 
hydrophilic (repel and attract water).  Microgravity allows for the observation of 3D assembly of 
submicron particles that would sediment on Earth.  This work is done on ISS with the aid of the the 
Light Microscopy Module (LMM) to lay the foundations for colloidal engineering (how to build 
nanobots) using Janus particles.
• ACE-T-1 will study colloidal engineering with an emphasis on self-assembly, which spontaneously 
forms precisely organized structures by thermodynamic equilibrium.  This work has the promise of 
providing efficient and affordable manufacturing processes for functional devices and materials with 
novel or enhanced properties.  The complex structures that result from self-assembly at the molecular 
level are regulated by highly specific and directional interactions. In contrast, colloidal building blocks 
are generally limited complex and highly ordered structures because of their highly symmetric 
potentials (e.g., electrostatic and van der Waals interactions tend to dominate). The shape anisotropy 
of colloidal building blocks promises to be a workable alternative that will enable shape-selective 
interactions with directionality specificity designed for building significant complex structures.
Science Background and Hypothesis – 1/2
Science Background
Hypothesis
Fundamental science and colloidal engineering can be 
pursued and understood directly at a particle level. 
Microscopy enables scientists to directly observe what is 
happening at a colloid particle level - one no longer 
requires a theoretical model to hope to connect 
macroscopic experimental observations to microscopic 
ones  (as when observing experiments at the size scale 
seen with a photograph taken of a BCAT or PCS sample).
Science Background and Hypothesis – 2/2
Microscopic self-assembly
1. Combination of force
2. Shape
3. Topology
New Functional Materials
Particle assembly
Ref.: Science, 306, 2004
Nature materials, 10, 2011
Novel building block
“atoms” & “molecules” of tomorrow’s materials
ACET1 (CNU) investigation goals and objectives
Microscopic self-assembly
Plan 1
Hydrophobic domain 
Hydrophilic domain
Anisotropic building blocks 
(Janus amphiphilie)
Ground state
“Sedimentation” 
Microgravity
“Self-assembly”
Programmed assembly for dimers
Low probability of assembly in the ground state
Microscale building block 
(Janus lock & Hydrophobic key)
Programmed assembly for dimers
Lock Key
Ground state
“Sedimentation” 
Microgravity
“Self-assembly”
Low probability of assembly in the ground state
Microscopic self-assembly
Plan 2
Microscale building block 
(Janus lock & Hydrophobic key)
Programmed assembly
(analogy Multivalent ligand)
Lock Key
Ground state
“Sedimentation” 
Microgravity
“Self-assembly”
“1 Key + N Locks”
Low probability of assembly in the ground state
Microscopic self-assembly
Plan 3 (analogy multivalent ligand)
We will be using a flight-hardened Commercial-
Off-The-Shelf (COTS) microscope
[pictured on next page]
and an 
ACE-T sample module
[pictured later]
Measurement approach
Light Microscopy Module (LMM) in the Fluid Integrated Rack (FIR)
Measurement approach – 1/9
LMM Implementation Philosophy
Payload Specific Hardware
• Sample Cell with universal Sample Tray
• Specific Diagnostics
• Specific Imaging
• Fluid Containment
Multi-Use Payload Apparatus
• Test Specific Module
• Infrastructure that uniquely meets 
the needs of PI experiments
• Unique Diagnostics
• Specialized Imaging
• Fluid Containment
FCF Fluids Integrated Rack
• Power Supply
• Avionics/Control
• Common Illumination
• PI Integration Optics Bench
• Imaging and Frame Capture
• Diagnostics
• Environmental Control
• Data Processing/Storage
• Light Containment
• Active Rack Isolation System (ARIS)
Payload specific and multi-user
hardware customizes the FIR in a
unique laboratory configuration to
perform research effectively.
Light Microscopy Module
Philosophy: Maximize the scientific results by utilizing the existing LMM 
capabilities. Develop small sample modules and image them within the 
LMM
Measurement approach – 2/9
Measurement approach – 3/9
Light Microscopy Module
(LMM)
ACE Sample Assembly with 
Removable ACE-T Sample Tray 
that will contain a row of 3 
temperature controlled 
capillary cells
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Mechanical Design Highlights
7/17/15 ACE-T Critical Design Review (CDR) 14
 Modular sample 
assemblies
 Allows for multiple 
sample configurations.
 Easier Sample replacement
 Decreased “ACE-T” up-mass 
in comparison to ACE-H
Measurement approach – 4/9
Mechanical Design Highlights
7/17/15 ACE-T Critical Design Review (CDR) 15
Measurement approach – 5/9
Mechanical Design Highlights
7/17/15 16
• In-situ mixing 
(details in 
electrical section)
• Black Hard 
Anodize Surface 
Coat
– Reduction of any 
errant light 
within the AFC
– Increased wear 
resistance
ACE-T Critical Design Review (CDR)
Measurement approach – 6/9
Mechanical Design Highlights
7/17/15 17
Capillary cell
• Purchased through VitroCom.com
• Material
– Borosilicate (3520-050)
– Fused Silica by request (3520S-050)
• COTS 
• 50mm length
• Reference Marks
– Secondary Process to ease positional 
awareness
ACE-T Critical Design Review (CDR)
Measurement approach – 7/9
Two capillary cells surrounded by inductors that are 
used for walking a turning stir-bar for sample mixing.
Temperature gradient option
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• Thermal bridge
– Material: Copper
– Bridges thermal energy 
between TEM’s
– Constrains Thermistor 
Positioning
– Thermal symmetry 
across X and *Y Axis
*When set-points are equal
Measurement approach – 8/9
Liquid         Liquid-solid            FCC           “Glass”
coexistence            crystal
0.494 0.545 0.58 0.63 0.7404
Volume frac tion
Ø 
Random
close
packing
Crysta l
c lose
packing
Hard Sphere Equilibrium Phase Diagram
Bonus information:  ACE-T, in general, 
will enable temperature control that 
can either be linear across the capillary 
- or a temperature gradient across the 
capillary.  A temperature gradient will 
form a density gradient!  You can now 
march through a phase diagram using a 
single capillary and have a common 
error bar for all measurements. 
The experiment consists one control base and two interchangeable samples modules  (each sample module contains 
three capillary cells). Run one experiment module per week. Microscopic observation is expected to require 1–4 days 
for each sample module.  
1. Inspect samples (to determine whether or not large bubbles exist in the sample capillary cells).
2. The first sample to be run will be selected based on the above bubble size observations; from this, feedback will be 
provided to the crew on which sample well strips to install in the microscope. 
3. Mix sample wells using motorized magnetic stir bar in the condenser until that particles are randomized; ground 
testing will be used in advance of the flight to ensure that 2 minutes per capillary cell is appropriate.
4. Define XYZ offsets (assembly alignment per ACE-T-1 method) and camera parameters are adjusted using 25x 
objective.
5. Survey capillary cell(s) at 25x to determine primary test locations (select locations away from stir bar or bubble) and 
secondary region of interest.
6. Move to first regions of interest (ROI). Using 40x air objective, focus on the bottom surface of the particle assembled 
structure. 
7. Operator records camera parameters using the 40x air objective and records best z-depth at each primary test 
location (record at five z-depths (e.g. 2, 4, 6, 8, and 10 microns) each region of interest (ROI).
8. We would like to use 40x air objective at intervals of 3 hours for 4-5 days.  Addition experimentation with the GIU will 
tell us if we need to switch to 63x air objective to see the bond structures.
9. Imaging goal is to characterize and analyze the assembled formation/structures. 
Measurement approach – 9/9
Expected results and how they 
will advance the field (1/2)
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The microgravity environment on the ISS will provide an 
understanding of the fundamental physics of anisotropic 
particles, which in turn will tell us what kinds of 
structures are possible to fabricate.  This enables us to 
prescreen which high-value products merit the 
investment of manufacturing resources.
Expected results and how the expected results 
will advance the field (2/2)
Prof. Chang-Soo Lee 
Department of Chemical Engineering, 
Chungnam National University (CNU), 
South Korea
2D experiments possible on Earth. 
On ISS self-assembly will be observed and understood  in 3D.
Earth benefits / spin-off applications
The ACE-T-1 investigation seeks to answer fundamental 
questions about behaviors of colloids, helping scientists 
to understand how to control, change, and even reverse 
interactions between tiny particles. This knowledge is 
crucial for developing self-assembling, self-moving, and 
self-replicating technologies for use on Earth.  It is 
anticipated that this novel fabrication approach can be 
applied to produce novel functional material in various 
applications such as self-assembly, photonics, 
diagnostics, and drug-delivery.
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ACE-T1
Increment 45/46 Science Symposium
BACKUP SLIDES
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Maximum fluid volume of each sample well  There are 10 wells per sample cell (Maximum volume of each sample cell well = approximately 1.25μL)
In the case of well #2, 6, 10, stir bar (1mm length and 0.076mm in diameter) and external magnet for mixing can be added to each well, which increase the contact frequency of microparticles.
Particle information
Janus particles bearing segregated hydrophobic and hydrophilic parts are composed of TMPTA (trimethylolpropane triacrylate) with lauryl acrylate as comonomer and PEG-DA (polyethyleneglycol
diacrylate), respectively.
- Schemes for particle assembly
1. Type A (Well #1 – #2): Cylindrical Janus particles with 5 × 5 μm dimension (mixing/ non-mixing)
2. Type B (Well #3 – #6): Cylindrical Janus particles with 20 × 30 μm dimension (mixing/ non-mixing)
3. Type C (Well #7 – #10): Convex Janus particles with 20 × 30 μm dimension  (mixing/ non-mixing)
The Janus particle with different ratio of hydrophobic/hydrophilic part is prepared (e.g., hydrophobic/hydrophilic part = 7:3, 5:5, 3:7)
Media Solutions
Media solution = De-ionized water (0.01% Tween20 as surfactant can be used to prevent adhesion of the particle on vessel)
Well # Sample Cell 
1
Particle
Media
Particle Volume 
Fraction
* Mixing with motorized stir bar
Cylindrical Janus particle (hydrophobic/hydrophilic ratio=5:5), Size: 5 μm x 5 μm  (width x height, A.R=1, cylindrical shaped Janus particle)
De-ionized water
0.0025-0.005 (50-100 particles/1.25μL)
2
Particle
Media
Particle Volume 
Fraction
* No Mixing 
Cylindrical Janus particle (hydrophobic/hydrophilic ratio=5:5), Size: 5 μm x 5 μm  (width x height, A.R=1, cylindrical shaped Janus particle)
De-ionized water
0.0025-0.005 (50-100 particles/1.25μL)
3
Particle
Media
Particle Volume 
Fraction
* Mixing with motorized stir bar
Cylindrical Janus particle (hydrophobic/hydrophilic ratio=3:7), Size: 20 μm x 30 μm  (width x height,  A.R=1.5, cylindrical shaped Janus particle)
De-ionized water
0.0025-0.005 (50-100 particles/1.25μL)
4
Particle
Media
Particle Volume 
Fraction
* Mixing with motorized stir bar
Cylindrical Janus particle (hydrophobic/hydrophilic ratio=5:5), Size: 20 μm x 30 μm  (width x height,  A.R=1.5, cylindrical shaped Janus particle)
De-ionized water
0.0025-0.005 (50-100 particles/1.25μL)
5
Particle
Media
Particle Volume 
Fraction
* Mixing with motorized stir bar
Cylindrical Janus particle (hydrophobic/hydrophilic ratio=7:3), Size: 20 μm x 30 μm (width x height,  A.R=1.5, cylindrical shaped Janus particle)
De-ionized water
0.0025-0.005 (50-100 particles/1.25μL)
ACE-T1 samples, 1/2
[3-13-2015]
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ACE-T1 samples, 2/2
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Particle
Media
Particle Volume 
Fraction
* No Mixing 
Convex Janus particle (hydrophobic/hydrophilic ratio=3:7), Size: 20 μm x 30 μm  (width x height,  A.R=1.5, convex top)
De-ionized water
0.0025-0.005 (50-100 particles/1.25μL)
7
Particle
Media
Particle Volume 
Fraction
* Mixing with motorized stir bar
Convex Janus particle (hydrophobic/hydrophilic ratio=3:7), Size: 20 μm x 30 μm (width x height,  A.R=1.5, convex top)
De-ionized water
0.0025-0.005 (50-100 particles/1.25μL)
8
Particle
Media
Particle Volume 
Fraction
* Mixing with motorized stir bar
Convex Janus particle (hydrophobic/hydrophilic ratio=5:5), Size: 20 μm x 30 μm  (width x height,  A.R=1.5, convex top)
De-ionized water
0.0025-0.005 (50-100 particles/1.25μL)
9
Particle
Media
Particle Volume 
Fraction
* Mixing with motorized stir bar
Convex Janus particle (hydrophobic/hydrophilic ratio=7:3), Size: 20 μm x 30 μm  (width x height,  A.R=1.5, convex top)
De-ionized water
0.0025-0.005 (50-100 particles/1.25μL)
10
Particle
Media
Particle Volume 
Fraction
* No Mixing 
Convex Janus particle (hydrophobic/hydrophilic ratio=5:5), Size: 20 μm x 30 μm (width x height, A.R=1.5,  convex top )
De-ionized water
0.0025-0.005 (50-100 particles/1.25μL)
[3-13-2015]
Mission Success Criteria for ACE-T1 (Lee)
Success Level Accomplishment
Minimum Success
Minimal success can be evaluated by successful loading of particles into cells, monitoring of the particles, and 
capturing of the particle or assembly images under the microgravity environment although particle assembly has 
not happened.  In addition, images of assembly of microparticles are captured at 3 hour intervals over a period of 
1 day.
Significant Success
Significant success would be realized if all plans were showing possibility of assembly, but not fully accomplished.  
There are small portion of the particles assembly in a cell while some particles are moving individually because of 
lack of attractive forces (e.g., chemical attraction, depletion force, surface tension force and so on). In addition, 
images of assembly of microparticles are captured at 3 hour intervals over a period of 3 days.
Complete Success
Complete success is that most of particles in all conditions would be directionally assembled by attractive force.  
We can obtain various configurations of assembled types from dimer to multimer or time-lapse images including 
the kinetic information of the assembly under the microgravity environment. In addition, images of assembly of 
microparticles are captured at 3 hour intervals over a period of 7 days.
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Microgravity Justification
• Formation of colloidal structures is profoundly affected by gravity via sedimentation 
processes.  Chaikin and Russel have already demonstrated this effect in space experiments 
exploring the simplest of all entropic transitions, the hard-sphere liquid-solid phase 
transition.
• Sedimentation causes particles to fall so rapidly that there is insufficient time for particles 
to explore the full phase space of positions and velocities that are required for 
thermodynamic assembly processes.  A substantial particle concentration gradient arises 
in the earthbound sample. 
h= gravitational height
K T = Thermal Energy of system
Dr is the density difference between the particles and the background 
fluid
V is the particle volume
g is the gravitational acceleration
h ranges from a few microns for the case of polystyrene in water to a fraction of 
a micron for most of the other particles we consider.  Our particles are usually 
of order 1 micron in diameter.
h=
k T 
Dr V g
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• In addition, the shear forces of fluid flow due to the sedimenting particles is 
often sufficient to break structures that are forming thermodynamically.
• The solvents we plan to use (such as water) are restricted by various 
factors, for example by our need to fix the colloidal structures in space.  
Almost all of the particles of future interest are either too heavy or too light 
compared to water.  
• Sample equilibration often requires ~1 to 12 hours.  Structure growth 
sometimes continues for one to two more weeks after the initiation process. 
These processes are too slow for a drop tower or an airplane.
• Space station or space shuttle provides an environment where microgravity 
is sustained long enough to allow these experiments to be conducted.  The 
samples can be homogenized, and then allowed to develop in the 
microgravity environment.  Their structures and optical properties can be 
measured. For most samples we are contemplating, the density mismatch 
between particle and background fluid is large (e.g. > 1.1 x).  Microgravity 
dramatically reduces these differences and permits true equilibrium 
processes to occur.
(continued)Microgravity Justification


Advanced Colloids Experiment (ACE-T1)

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