What is Adhesion: Definition and 29 Discussions

Adhesion is the tendency of dissimilar particles or surfaces to cling to one another (cohesion refers to the tendency of similar or identical particles/surfaces to cling to one another).
The forces that cause adhesion and cohesion can be divided into several types. The intermolecular forces responsible for the function of various kinds of stickers and sticky tape fall into the categories of chemical adhesion, dispersive adhesion, and diffusive adhesion. In addition to the cumulative magnitudes of these intermolecular forces, there are also certain emergent mechanical effects.

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  1. smiddleton26

    Misc. Expand balloon with static electricity

    The idea is to wrap a balloon in several layers of material, similar to that used in electrostatic adhesion wall climbing robots, and run power through the layers. The electrostatic charge on the layers outside the balloon will build up and the air inside the balloon will begin to become...
  2. A

    Help Identifying Source of Sliding Adhesion Coefficient Equation

    Hello all, I am a graduate student working on a thesis in tire dynamics and simulation. I have came across the following equation for sliding adhesion coefficient for the HSRI tire model (source: Schramm et. al. Vehicle Dynamics, Modeling and Simulation, pg. 182): Unfortunately, Schramm et...
  3. Hyperbolu

    I Adhesive Collision: Coding for Sticky Objects

    I am trying to code collision of two objects. When they collide, instead of rebound or motion of them according to their velocity, i want them to stick together and move in direction of resultant normal velocity. It is not plastic collision. I want a force that stops the rebound. how can i...
  4. V

    Analysis of a Frictional Contact Problem with Adhesion

    Hi, I'd to work with a model which represents a contact problem. I want to suppose that f_0=0 and f_2=0 where f_0 is a density of body forces and f_2 is a density of surface tractions . I am mathematician so I don't know if the hypothesis that I'd to suppose will make the problem have a sense in...
  5. M

    Focal Adhesion Kinase and the MAPK pathway

    The above image (source) is pretty much the only thing we're told about how the MAPK pathway is activated. However, in passing, FAK was mentioned. We were told that focal adhesion integrins activate FAK which then activates the MAPK pathway. Seen in the image (source) below However the two...
  6. Amaterasu21

    B Why don't solids always stick together?

    Hi all, Something I've been wondering - why don't two solid surfaces always stick together when touching each other? As far as I'm aware there are five basic types of solids: Atomic solids: Frozen noble gases containing single atoms held together by London dispersion forces. Molecular...
  7. A

    Mercury adhesion and wetting to plastics/polycarbonate/glass

    Hi, I am starting to make some experiments with my project and part of it involves developing a small MHD system. Now for test purposes and ease of manufacturing I have decided I want to use some clear see through plastic which would help me see whether my experiment is working as planned. My...
  8. T

    Tensile Test Results: Adhesion of Tape to Plastic Surface

    Hello, I am currently writing my thesis, where I have to investigate if a surface treatment increases the adhesion (between tape and a plastic surface). For this purpose, I have among other tests, performed a tensile test between the tape and plastic surface. The tensile test can be separated...
  9. C

    What is the weight increase of a dredge when hoisting it out of water?

    I am a crane operator and have prob, a very simple question for any of you. I set a dredge in a pond and when I set it in the water it weighed 80,000 lb. My question is when I'm hoisting it back out how much will the weight increase before it is free from the surface of the water.
  10. D

    I Adhesive Forces: Bigger vs. Smaller Straws

    Is the adhesive force greater in a smaller tube then a bigger tube at the top? So would it take more energy to take out water at the top of the straw from the thinner straw? Or would, due to gravity cancelling eventually the capillary rising, the adhesive force at the very top of the straw is...
  11. M

    Metal thin film adhesion, Au-Si deposition

    What protocol should I use to get a good stable 100nm Au adhesion onto a Si substrate using electron beam evaporation? I've heard talk of primer layers of either Cr or Ti at around 5nm thickness, as the typical way to do it. Which material should I choose? What the advantages or disadvantages...
  12. jtdrexel

    What causes ‘Sticking’ in pharmaceutical tablets?

    Pharmaceutical tablets are formed by compressing powder in a die by metal punches until a compact is formed. The term ‘Sticking’ refers to a phenomenon that results in the adherence of material onto the punch faces and die wall even after the metal has left contact with the tablet. I am...
  13. S

    A Adhesion mechanism between titanium and gold?

    Hi all, I sputtered titanium (10 nm) - gold (~ 100 nm) films at room temperature on oxidized silicon substrates. The titanium acts as an adhesion promoter between the SiO2 and the gold film. My Question: What is the adhesion mechanism between the titanium and gold film at room temperature...
  14. T

    B Need help understanding tires and adhesion

    According to physics F=mu×N. With tires there has to be more that applies. To increase friction, you have to run a stickier rubber compound tire (mu) or increase downforce like with aerodynamic parts (N). But why is it that if you install a new set of tires that is the same coefficient of...
  15. Y

    Resist adhesion to Borosilicate glass for BOE etching

    Hi all, I have had a problem in etching Borosilicate glass using BOE (6:1). As etching continues in the channel, the photoresist near the channel gradually peels off and when etching finishes (100nm), the lateral distance of peeled-off resist is big--about 6 microns. Anybody have a great...
  16. J

    Relationship between adhesion and friction

    Maybe this question is pretty simple to tackle, but I’m really confused with it. Perhaps I’m just overthinking. The question is: The glue on a piece of tape can exert forces. Can these forces be a type of simple friction? Explain, considering especially that tape can stick to vertical walls...
  17. E

    Max Diam Tube Filled w/ Viscous Liquid: Deriving Formula

    Formula for the maximum diameter of vertical tube(open on top and bottom) filled with viscous liquid (such as oil) as a function of viscosity and length so that the liquid remains inside. How the formula is derived? Thanks a lot.
  18. R

    3d printing with Polylactic acid, adhesion to print bed

    I recently built a 3d printer that extrudes PLA or Polylactic acid for the material. When printing on a glass bed the pla drags behind the extruder because it won't stick to the glass. On the other hand printing on a sheet of acrylic the PLA sticks so well that it is difficult to remove after...
  19. R

    3d printing with Polylactic acid, adhesion to print bed

    Polylactic acid (PLA) is a very popular raw material used for plastic extrusion 3d printers. Myself and many others in the 3d printing community have have experienced difficulty getting the the first layer to stick to the bed. I have tried a couple things so far 1) Heated smooth glass bed...
  20. R

    Does Higher Surface Energy Influence Adhesion and Wetting in Similar Materials?

    Consider comparasion between same states and same type of materials. also consider the substrates to have same surface quality. a substance with higher cohesive force would have a higher surface energy. this should be because of the stronger cohesive forces between molecules as the molecule...
  21. J

    How Can I Create an Electrostatic Adhesion Gripper for My Robotics Project?

    G'day, I've got a little robotics project that I'm working on, and I've been thinking of adding a little electro-static adhesion gripper to it. This gripper will used to pick up an aluminium softdrink can (300ml I think), which weighs 100gm. At the moment, I don't care what it can pick up...
  22. G

    Cell adhesion intimately linked to metabolism?

    Integrin-PI3K-Akt signal transduction is well known. Akt signaling has been heavily reviewed and is well known to play a role in metabolism. So why do I have difficulty finding any research that has linked cell adhesion to metabolism? It would make sense. If a cell became cancerous, one way...
  23. D

    What to do to improve Cu adhesion?

    I'm doing some growths on Cu/SiO2/Si stacks at temps around 800C. I'm getting adhesion issues clearly, and I know Cu definitely doesn't do that well. What would be recommended? Should I put down a layer of Cr (or anything else?) first? And how thick of a layer? My SiO2 is about 1 micrion and...
  24. J

    Vacuum adhesion vs hovercraft

    I am doing a senior design project for a mechanical engineering degree. The project I am doing hinges on my teams ability to create a stable platform capable of adhering to a vertical, semi-permeable surface. Presently our greatest challenge is sorting out the mathematical proof of concept for...
  25. S

    Adhesion of Al and Au: Investigating the Bond

    Dear all: I wonder how the adhesion between Al and Au is. I am going to deposit Au on top of Al layer. Regards.
  26. S

    Exploring the Role of Van Der Waal's Adhesion in Glue and Gecko Setae Bonding

    I have researched a little online and apparently Van Der Waal's adhesion forces play a key role in the sticky properties of glue and the bonding between gecko setae and tree surfaces. What I don't understand is why this adhesion doesn't happen between the surfaces of any two solids brought in...
  27. A

    Which oxide improve the gold adhesion

    Hi everybody, I need to deposit 50 nm of gold on a transparent oxide layer. I need that this oxide layer would have a refractive index of 2, at the wavelenght 1.5 micron (infrared). I first tried with SiO2 but as many of you know the adhesion is very poor. Then I tried with ZrO2 and it...
  28. N

    How can we explaine the adhesion force?

    Hello, How can we explain the adhesion force between two different materials, for instance Glass and honey, or glass and water. if we put a droplet of honey why it does stick more firmly than a droblet of water? what are the forces reponsible on that ? I'm looking to atomic scale...
  29. R

    How are Cell Adhesion and Detachment Different?

    Hello all, I am reading some primary literature in which they talk about cell adhesion and cell detachment. They describe different assays for each. My question is, how are these two different? It seems that high detachment is the same as low adhesion, but according to the article, for a...