Download - PM Adhesion
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NORTHEASTERN UNIVERSITY
Department of Chemical Engineering
CHEM 2311 Transport 1 Laboratory
January 23rd, 2015
TO: Tracy Carter & CHME 2311
FROM: Zachary Parrella, Margaret Hayes, Abdulrasheed Oseni, Alex
Caraballo
SUBJECT: Adhesive Properties between Liquids and Surfaces; Contact Angles
which uses adhesive forces to allow humans to scale vertical walls, just like theeponymous gecko. By analyzing the contact angles between different fluids and determined; that is what materials it will work on, what materials it can be made out of,and the maximum slope that it will remain functional.
Objectives: The objective of this lab is to verify the Tadmor/Chibowski equation, which
relates the advancing and receding contact angles of a specific liquid on a specific
surface and gives a theoretical contact angle, by comparing it to a measured,
experimental contact angle.
Background:
Adhesion, defined in the most general sense, is the ability for unlike molecules tocling to each other. For f
can cling to a certain surface, and is strongly tied to the strength of the intermolecular
example, water is highly cohesive, due its ability to form hydrogen bonds and its nature
as a polar molecule
the electrostatic attraction between the polar water molecules and the glass molecules
acts as an adhesive force; in the case of water, this adhesive force is greater than the
cohesive force, resulting in the formation of the concave up meniscus.
forces between the fluid and the surface are greater than the cohesive forces within the
fluid.
Due to the weak intermolecular forces present in gases, the engineers are often
adhesive properties vary wildly depending on the surface it interacts with, engineers
measure what is called a contact angle: the angle between where the liquid touches the
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surface and where the liquid touches the air. For a given liquid, a given surface, and a
given temperature and pressure, there is a unique contact angle for when the system is
at equilibrium. The magnitude of this contact angle indicates the degree of adhesion
between that liquid and that surface. Large contact angles indicate that the liquid is not
wetting the surface very well; sufficiently large angles will result in the liquid beading up
and sliding off the surface completely (as demonstrated by super hydrophobic
surfaces). Low contact angles, conversely, indicate a very large degree of adhesion as
the liquid thoroughly wets the surface. Sufficiently small contact angles will result in
almost no droplets forming at all as the liquid completely flattens itself against the
surface, as seen with super hydrophilic surfaces.
The most obvious application of adhesion is, of course, producing adhesives and
making things stick together. This is, however, far more interesting than it seems at first.
For instance, by using adhesive ferromagnetic liquids, the adhesion of a liquid to a
surface can manipulated to pr
, this technology manipulates the cohesiveness of a liquid, and,
subsequently, its adhesiveness. Another possible application of adhesion is to use
specially designed materials and surface contours to replicate the wall-climbing abilities
of spiders or geckos. By manipulating the actual area where the liquid and surface
interact, the relative strength of the adhesive force of a liquid is changed.
Despite the widespread applicability of adhesion, the fact that the adhesive
properties of a liquid are dependent on so many variables has made contact angles
difficult to tabulate. Of the surfaces were are testing, only water has readily available
information on its various contact angles; even then, most of these contact angles arefor polymers designed to specifically be hydrophobic or hydrophilic.
Apparatus and Materials:
Water
Vegetable Oil
Corn Syrup
Ketchup
Wood Glass
Metal
Stone Tile
Brick
Pipette
ProScope Camera
Paper towels
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Safety Analysis:
Of the materials used in this investigation, only two have the capability to be
chemically hazardous; corn syrup and ketchup. Corn syrup may cause irritation of the
respiratory tract if inhaled and may cause allergic skin reaction if it gets in contact with
skin. However these hazards are minimized simply by having adequate skin covering
with gloves, long sleeve clothing, and protective goggles as well as taking care as not to
inhale the liquid. If spilled, all ignition sources must be moved away from the spill in
order to prevent possible fire.
Ketchup can also be hazardous if allowed to enter the eyes or if accidentally.
swallowed. If accidentally inhaled, the effects can be mitigated by moving to a fresh air
location. If it enters the eyes, thorough cleansing with water for 15 minutes is enough to
stop its eye irritation effects.
The major piece of equipment used is the Proscope which is used to measure
the contact angle of the droplets. As with all electronic devices, liquids must beprevented from getting in contact with it. The device itself however provides no real
hazardous threat to the operator.
In order to ensure system safety and prevent potential hazards, liquids and
electronics will be kept apart and all personnel will have on adequate safety equipment.
In the instance of a hazard, the hazard will be identified and the necessary action will be
taken.
Procedure:
1. Mount the Proscope vertically on the side of the table and launch the ProScope
software.2. Choose a surface to be tested first and place it in front of the ProScope Camera.
3. Pipette a drop of water onto the surface in front of the camera.
4. Measure the contact angle using the ProScope software. Choose the angle
measurement icon. Click the center of the droplet where the liquid meets the solid, drag
the cursor to the edge of the droplet and then up along the curve of the droplet as shown
properties of the surface?
(Bai, n.d.)
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5. Once the contact angle has been measured, begin to tilt the surface until it has reached
the point that the droplet is about to fall. At this point, measure the advancing contact
a r t as shown below. Use these
values to calculate the theoretical contact angle using the Tadmor/Chibowski equation.
With the experimental and theoretical values for contact angle, calculate the error. Whatdoes the tilt angle say about the adhesive properties for each surface?
(Ramé Hart, 2013)
Tadmor/Chibowski Equation:
(Chibowski, 2013)
6. Repeat this process 3 times. Then repeat the process for the three other surfaces. Besure to wipe down the surface before adding another droplet. How do each of the
different surfaces affect the adhesion of the water to the surface?
7. Repeat the process again, except this time rather than changing the surface, change the
liquid. Test all liquids on the metal. Water does not need to be repeated. Which liquids
seem to adhere to the metal best?
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Example Calculation:
Receding contact angle () = 35° Advancing contact angle () = 110°Measured equilibrium contact angle () = 20°
Using Tadmor/Chibowski equation to find the experimental equilibrium contact angle:
References:
Bai, Baojun. Con t a c t Angl e . Digital image. RP S EA. Missouri S&T, n.d. Web. 19 Jan. 2015.
Comyn, John. Adhesion Science. Cambridge: Royal Society of Chemistry, Information
Services, 1997. Print.
Mittal, Kash L. Contact Angle, Wettability and Adhesion, Volume 6. Hoboken: CRC, 2009.
Print.
Ti l t . Digital image. Ra m é H ar t . Ramé-Hart Instrument Co., Oct. 2013. Web. 19 Jan. 2015.
"Wetting." Wetting. Adhesive and Sealant Council (ASC), 2008. Web. 19 Jan. 2015.
"2014/06/05 DARPA Z-Man Program Demonstrates Human Climbing Like Geckos."
DARPA R SS . DARPA, 5 June 2014. Web. 19 Jan. 2015.
.
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"Adhesion and Cohesion of Water." Adh e s ion and Coh e s ion Wa t e r Prop e r t i e s , U S G S Wa t e r
S c i e n ce S c hool . US Geological Survey, 17 Mar. 2014. Web. 18 Jan. 2015.
Angl e o f Con t a c t ( S T6A) . Perf. Ashish Arora. YouTub e . YouTube, 25 Apr. 2012. Web. 19 Jan.
2015. .
Anhydra - Hydrophili c and Hydrophobi c S ur f a ce s . You t ub e . Youtube, 1 Aug. 2012. Web. 19 Jan.
2015. .
2014. Retrieved 19 Jan. 2015 from
https://www.boundless.com/biology/textbooks/boundless-biology-textbook/the-chemical-foundation-of-life-2/water-51/water-s-cohesive-and-adhesive-properties-
286-11419/
Different
391 399. PMC. Web. 20 Jan. 2015.
"Contact Angle." KRÜ SS G m bH . KRÜSS GmbH, n.d. Web. 19 Jan. 2015.
.
"Critical Surface Tension and Contact Angle with Water for Various Polymers." Cri t i c al S ur f a ce
T e n s ion and Con t a c t Angl e wi t h Wa t e r f or Variou s Poly m e r s . Accu Dyne Test, 2009.
Web. 19 Jan. 2015. .
"Critical Surface Tension, Surface Free Energy, Contact Angles with Water, and Hansen
Solubility Parameters for Various Polymers." Cri t i c al S ur f a ce T e n s ion , S ur f a ce F r ee
En e rgy , Con t a c t Angl e s wi t h Wa t e r , and Han s e n S olubili t y Para m e t e r s f or Variou s
https://www.youtube.com/watch?v=YYy8WTixboghttps://www.boundless.com/biology/textbooks/boundless-biology-textbook/the-chemical-foundation-of-life-2/water-51/water-s-cohesive-and-adhesive-properties-286-11419/https://www.boundless.com/biology/textbooks/boundless-biology-textbook/the-chemical-foundation-of-life-2/water-51/water-s-cohesive-and-adhesive-properties-286-11419/https://www.boundless.com/biology/textbooks/boundless-biology-textbook/the-chemical-foundation-of-life-2/water-51/water-s-cohesive-and-adhesive-properties-286-11419/https://www.boundless.com/biology/textbooks/boundless-biology-textbook/the-chemical-foundation-of-life-2/water-51/water-s-cohesive-and-adhesive-properties-286-11419/https://www.boundless.com/biology/textbooks/boundless-biology-textbook/the-chemical-foundation-of-life-2/water-51/water-s-cohesive-and-adhesive-properties-286-11419/https://www.boundless.com/biology/textbooks/boundless-biology-textbook/the-chemical-foundation-of-life-2/water-51/water-s-cohesive-and-adhesive-properties-286-11419/https://www.boundless.com/biology/textbooks/boundless-biology-textbook/the-chemical-foundation-of-life-2/water-51/water-s-cohesive-and-adhesive-properties-286-11419/https://www.youtube.com/watch?v=YYy8WTixbog
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Poly m e r s . Accu Dyne Test, 2009. Web. 19 Jan. 2015.
.
Ewoldt, Randy H., Piotr Toukine, Gareth H. McKinley, and A. E. Hosoi. "Controllable Adhesion
Using Fluid-Activated Fields." (n.d.): n. pag. MIT. Web. 19 Jan. 2015.
.
"History of Adhesives." B e aring S p ec iali sts Ass o c ia t ion (2014): n. pag. B e aring S p ec iali sts
Ass o c ia t ion . Bearing Specialists Association. Web. 19 Jan. 2015.
.
Hoffman, Allan S., and Buddy Ratner. "Lecture on Contact Angles." 19 Jan. 2015. Web. 19 Jan.2015..
Main, John. "Z-Man." DARPA R SS . DARPA, n.d. Web. 19 Jan. 2015.
.
Munson, Bruce Roy, T. H. Okiishi, Wade W. Huebsch, and Alric P. Rothmayer. "Surface
Tension." Funda m e n t al s o f F luid M ec hani c s . 7th ed. Hoboken, NJ: John Wiley &
Sons, 2013. 25. Print.
Nave, R. "Surface Tension." S ur f a ce T e n s ion . N.p., n.d. Web. 19 Jan. 2015.
S up e r Hydrophobi c S ur f a ce and Magn e t i c Liquid - Th e S low Mo Guy s . Perf. Gavin Free and
Daniel Grunchy. You t ub e . General Electric, 6 Jan. 2014. Web. 19 Jan. 2015.
.
Tracy, Cameron, Ling Xie, and Irene Ly. "Cohesive And Adhesive Forces." Ch e m wi k i . UC
Davis, n.d. Web. 19 Jan. 2015.
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Yuan, Yuehua, and T. R. Lee. "Contact Angle and Wetting Properties." S ur f a ce S c i e n ce
T ec hniqu e s . Ed. Gianangelo Bracco and Bodil Holst. Vol. 51. Dordrecht: Springer,
2013. 3-34. Print.
Zisman, W.A. (1964). F. Fowkes, ed. Contact Angle, Wettability, and Adhesion. ACS. pp. 1 51.
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Data Tables
[all to be measured in degrees]
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Data Tables:
The data such as the contact angle which is measured by the proscope is quantitative.
This quantitative data then leads to a qualitative analysis of the strength of the
interaction between the liquids and the surfaces thus determining how the adhesiveness
of the liquid is impacted by what kind of liquid it is, the surface the liquid is applied too,
and the angle that the surface to which it is applied is oriented.
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Appendix:
Please use this checklist to review the safety of your experiment and address any safety
hazards before you begin. You may begin once your supervisor signs it:
Emergency Phone Number:
Personal Protective Equipment (Check Yes or mark Not Applicable (N/A)):
· Shirt, Long Pants, Socks, Closed Toed Shoes Yes N/A
· Hair Tied Back Yes N/A
· Loose Clothing Secured Yes N/A
· Safety Glasses Yes N/A
· Hard Hat Yes N/A
· Gloves (ie. thermal, latex ) Yes, Type: N/A
· Lab Coat Yes N/A
· Ear Plugs Yes N/A
System Safety:
· Over pressure: Maximum Instrument Pressure:
Atmospheric Other:
· Under pressure: Minimum Instrument Pressure:
Atmospheric Other:
· System Temperature:
Steam or Electrical Heat required: Yes No
Maximum System Temperature:
· Vapors Properly Vented
Yes No N/A
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· Electrical Hazards
Emergency Shut-Off Switch Number:
Lock/out-Tag/out Procedures:
Mitigation procedures:
· Environmental hazards:
System Drainage Valves that should be closed during normal operation:
Emergency Containment Procedure:
Equipment Safety:
· Equipment Limitations:
· Visual inspection of apparatus: All materials in working order Items need checking:
Comments:
Materials Safety
· SDS reviewed and present during the experiment (note if SDS missing)
Reviewed Missing N/A for Air or Water Only
Missing SDS:
· Chemical containers labeled:
Yes No N/A
· System Chemical NFPA Ratings: N/A Yes , if Yes identify:
Maximum Health Rating:
Maximum Flammability Rating:
Maximum Reactivity Rating:
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Special Information:
· Nonhazardous Liquids (Dilute down drain/ trash):
Identities:
· Hazardous Liquids (Hazardous Waste Container) :
Identities:
· Nonhazardous Solids (Trash):
Identities:
· Solids (Hazardous Waste Container)
Identities:
· Solids (Sharps Container)
Identities:
Date:
Experiment Start Time: Experiment End Time:
INITIALS OF CO-WORKERS:
INITIALS OF SUPERVISOR: TLC
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Proposal Grading Rubric Grade______/20 points
Participation 10%: _____/2 points
Participation Points Check
Chemical Hygiene 1&2 On-line
Training/Safety Check in/out
Sheet/attendance
2
Format 20%: ______/4 points
Format Detail Points Check
Consistent Font Use consistent font throughout
the document. Make sure all
fonts are legible including
those in figures and tables.
-0.1/x
Consistent
Spacing
Consistent margins, spacing
between headings,
paragraphs, figures, tables
and equations
Titles/Subtitles Use main titles given in
template, and subtitles whenappropriate. Do not use
subtitles unless there is more
than one.
-0.1/x
Page numbers Do not number the first page,
begin with 2 on page 2 in
lower right corner of the page.
-0.1/x
Number format For data, numbers less than
one have a zero before the
decimal (0.1) and use anumeral if it is data (5 ml) or a
number greater than ten (11).
Write out the name for
numbers less than ten if it is
not data (nine). Do not begin
a sentence with a numeral (9).
-0.1/x
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Equation format Use an equation number
located to the right of the
equation, define the variables
with consistent units that must
cancel.
-0.1/x
Table format Use a table number with a title
that relates to your objectives,
located ABOVE the table, put
grid lines on table. Include
units in title for data
columns/rows.
-0.1/x
Figure format Use a figure number with a
descriptive title that relates to
your objectives located BELOW
the figure, and figure axis must
have labels with units.
-0.1/x
Reference
format
Place a superscript number in
the order the reference
appears in the text next to the
referenced information. After
the recommendations section,
list the references with
numbers in the order they
appear in the document. Use
consistent formatting for each
reference type.
-0.1/x
Significant
figures
Significant figures of the
measurement should reflect
the sig. figs of the
measurement device. Sig figs.
of calculations should match
the number of sig. figs. of the
measurement. Use
appropriate sig. figs. in thetext, tables, figures, and
sample calculations.
-0.1/x
Use of color in
figures or
images
Make sure figures can convey
the point in black and white
format.
-0.1/x
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Consistent verb
tense
Use consistent verb tense-
typically future or present for
proposals and present or past
for reports.
-0.1/x
Consistent voice You may use 1st or 3rd personfor the Discovery Experiments,
but you MUST use 3rd person
for all subsequent written
documents. Be consistent
with either voice.
-0.1/x
Consistent Units Use a consistent unit system-
-0.1/x
Other -0.1/x
Communication 30%: _____/6 points
Communication Detail Points ck
Proof Read -0.2/x
Correctgrammar/Spelling
-0.2/x
Purpose and
Objectives
Concise and technically specific, quantify if
possible.
Background Contains literature to support the purpose,
objectives, procedure, and expected results
and conclusions.
-0.2/x
Procedure Step-by-step instructions for the
experiment, organize by objective.
-0.2/x
Experiment Diagram Diagrams of experimental apparatus should
highlight significant specifications. May
include a photo.
-0.2/x
Equipment and Material
Specifications
Lists equipment manufacturer, model/serial
number, power rating, operating limits,
-0.2/x
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and/or other significant specifications.
Include all materials and specific amounts.
Safety Analysis Personal protective equipment and
exposure procedures, material handling and
disposal, equipment and system safetyanalysis.
-0.2/x
Data Tables Data tables should be set up so that raw
data can be directly entered during the
experiment. Include units of actual
measurement.
-0.2/x
Appendix: Sample
Calculations, Other
Sample Calculations if applicable. Include
checked rubric. Include other supporting
documentation as necessary.
-0.2/x
Technical Points 40%:_____/8 points
Technical Points Check
Literature references that
support the purpose and
objectives.
-0.5/comment
Effectively used literature to
design experimental procedure.
-0.5/comment
Literature supports expected
results and conclusions;
effectively described how the
data will be interpreted,
sample calculations are
correct and include units:
-0.5/comment
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Certificates of Training