pm adhesion

8/20/2019 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

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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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