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Most recently purchased 20,000 shares of General Electric (GE) at $17.44. Got caught holding overnight, and the next day was their day to report quarterly earnings. Coupled with the foreclosure debacle, GE Q3 earnings coming in under and the DOW misbehaving that day, the GE stock tumbled well below $16.00 now leaving me somewhere in the negative $28,000 area. The question I now ask myself... Should I sell at a loss and move forward? How long will it take for GE to bounce back to around $17.44 from around $16 and change? Also, half the stock was purchased on Margin from TD Ameritrade. So there is about $35 per day in interest adding up. Any ideas from anyone? what would you do?

Chris/NJ

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#1 priority in trading --- protect your capital

 

ie.

if you planned to hold, hold.

if it hurts, cut.

if it hurts and you hold, you are not trading, you are hoping.

and hope is the biggest enemy of success in trading.

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Chris,

 

I would take a step back and analyze what was it that made you purchase the shares in the first place. Was it fundamental reasoning? Technically based? Once that is determined then you can decide if anything has changed now that this news is out. How long were you planning on holding the position? If you are still bullish on the position then hold it. If things have changed exit the position and move on to the next trade.

 

More so than the above info, you really want to have a game plan in place before getting into a trade. I personally don't trade around earnings releases because of the increased risk. The company could come out with terrible earnings and the stock could pop or the flipside as well. You will also want to have some type of target/stop in place before getting in. One of the biggest mistakes traders make is not having a plan before getting in. By not doing this you let emotions get in the way just like you are experiencing now. In your example if your stop was hit get out and move on. If GE begins to rebound then look to get back in.

 

Don't let this losing trade turn into a disaster. Live to fight another day. On the next trade make sure you have all this planned out before getting in. Hope this helps.

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Based on your statements, it seems that your trade was supposed to end before the market closed. SO DUMP IT. You made a mistake. Move on. If you can't stand losing, go see a psychologist. Don't let your account bare the burden of your short comings.

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I can't tell you how often my "hope" has just ended up losing me even more money. Seems when you really are looking to "just get even" or "bailed out" the opposite will happen.....

 

 

MMS

 

Like so many situations in trading the worst thing is if you do the wrong thing then apply hope and it actually comes out profitable.

 

What just happened has strengthened a dysfunctional behaviour and you will play the same sequence out again and again until you've finally convinced yourself to stop playing to hope (lost enough money).

 

I can't count the number of times I got away with something - only to lose everything I gained and more over the next 10 or 20 trades.

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First things first. You should never place a trade without a known strategy for that trade. Meaning, before you click to place that trade order you should already know answers to 2 important questions. 1) What's signaling you to make this trade at a specific entry point? 2) What predetermined criteria must happen to signal your exit point? As a result, you should have an idea of when to enter and when to exit. It seems as if you didn't have a strategy going into this trade, so I suggest take the lost, learn from your mistakes and try not to let it happen again. Good luck on your next trade!

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I have to agree with most everything that has been said. You need to have an exit plan before you ever put on the position. If it gapped below that then it should be sold. Also, you need to think about GAPS. They can happen in every market, even when they don't close on a daily basis or over the weekend. I have personally had large gaps on forex during news events.

 

Now back to the trade. The only reason I would hold, past my stop, which should never happen, but mistakes can be made. is because of the value of the company. GE is a good solid company with good management. They pay dividends and you have an expectation that it will go up over the long term. Why did they drop, news, earnings?

 

This is not hope or a guarantee, it could go the other way forever and become wothless, but the odds are still in your favor. Your account has to be able to not take a dent with this entire loss. So, if it does not hurt your trading and you can trade other stocks and make money and want to hold GE long term, then keep it. I know buy and hold is dead!

 

Just something else to think about, If you bought Apple last week at the high and it dropped $20 which it did..do you sell or hold...what was your plan? Will it go up or down from here, is it a solid company? The Odds are going up, but be ready for the correction and exit strategy.

BW

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I have to agree with most everything that has been said. You need to have an exit plan before you ever put on the position. If it gapped below that then it should be sold. Also, you need to think about GAPS. They can happen in every market, even when they don't close on a daily basis or over the weekend. I have personally had large gaps on forex during news events.

 

Now back to the trade. The only reason I would hold, past my stop, which should never happen, but mistakes can be made. is because of the value of the company. GE is a good solid company with good management. They pay dividends and you have an expectation that it will go up over the long term. Why did they drop, news, earnings?

 

This is not hope or a guarantee, it could go the other way forever and become wothless, but the odds are still in your favor. Your account has to be able to not take a dent with this entire loss. So, if it does not hurt your trading and you can trade other stocks and make money and want to hold GE long term, then keep it. I know buy and hold is dead!

 

Just something else to think about, If you bought Apple last week at the high and it dropped $20 which it did..do you sell or hold...what was your plan? Will it go up or down from here, is it a solid company? The Odds are going up, but be ready for the correction and exit strategy.

BW

 

Buy and hold is not dead at all. Buy and hold is as valid a stategy as it ever was.

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Have to respectfully disagree on buy and hold -- for now it is dead. At least in the classic sense of what people used to think/trade/do with it. Which was just buy almost any solid company and hold for the long-term. Considering indices like the Nasdaq have spent the better part of the last 10 years just rallying back to half of their peak - you can imagine how many companies - hundreds? thousands? will never return to their peak.

 

There's clearly a place though for long term holdings -- but, it has been different the last 10 years than when you could just plow your money into some top companies and just rely on the momentum of the markets over the years to send them higher. We haven't had that luxury in a long time.

 

MMS

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Have to respectfully disagree on buy and hold -- for now it is dead. At least in the classic sense of what people used to think/trade/do with it. Which was just buy almost any solid company and hold for the long-term. Considering indices like the Nasdaq have spent the better part of the last 10 years just rallying back to half of their peak - you can imagine how many companies - hundreds? thousands? will never return to their peak.

 

There's clearly a place though for long term holdings -- but, it has been different the last 10 years than when you could just plow your money into some top companies and just rely on the momentum of the markets over the years to send them higher. We haven't had that luxury in a long time.

 

MMS

 

MM,

 

Since the first stocks were traded under the buttonwood tree ( buttonwood?) the majority of companies that went public ceased to exist or merged. You could, then, say that buy and hold never worked if you are in the wrong stocks. Buy and hold does not eliminate the need to diversify and it does involve the need to do the unthinkable and add to a position when it is down. The difference being that you are not expecting it to go up in the next 5 minutes and you don't add when it is down 1 point.

 

If you buy Q's' and add to them and sit patiently, you'll be fine.

 

Nothing dies, its just sometimes easier than other times.

 

Regards,

 

MM

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Hi catsrevenge,

 

all what is said about the hope mode above, applies.

I only want to add a chart which I usually uses. It is based on the CCI as woodie uses it. There is a lot of free stuff around in the internet and even free chatrooms to learn more about the method.

After my humble opinion you entered the long right in the moment when th short trend started. The overnight gap is even a short entry sign for candle stick traders. Of course it can always flip around back long, you never know. There is unfortunately no certanty...

 

regards

d987

5aa7103f1954c_ge26_10.thumb.png.a784e9f533a6a1315bc20a7e45ca4b01.png

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Most recently purchased 20,000 shares of General Electric (GE) at $17.44. Got caught holding overnight, and the next day was their day to report quarterly earnings. Coupled with the foreclosure debacle, GE Q3 earnings coming in under and the DOW misbehaving that day, the GE stock tumbled well below $16.00 now leaving me somewhere in the negative $28,000 area. The question I now ask myself... Should I sell at a loss and move forward? How long will it take for GE to bounce back to around $17.44 from around $16 and change? Also, half the stock was purchased on Margin from TD Ameritrade. So there is about $35 per day in interest adding up. Any ideas from anyone? what would you do?

Chris/NJ

 

You can sell some calls to make some money and mitigate the losses.

For example, if you sell 200 call options January 2010 @ 15.00, you get something like 52100 to your pocket right away.

BigCharts - QuickCharts

You can buy some protection in buying puts of the same or shorter term.

 

In between now and Jan 2012 you can take advantage of ups and downs to get out of the stock even at a profit.

Maybe you should read a lot about options.

 

Your current loss in not the end of the world!

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For the OP:

As some wrote here before, you shouldn't have initiated a position without an exit plan. Also, I wonder why did you post here. The title says you are "Stuck" in a bad position. That's nonsense, you aren't stuck anywhere, unless you choose to. Have you already decided that you are stuck? Are you seeking confirmation for your attitude? As a matter of fact, nobody here knows what the stock will do next. So I'd recommend to you to think of different scenarios. First, imagine that you sell it now and the stock instantly turns to reach your breakeven without looking back. Second, imagine that you hold it and it continues falling, say to $10. Now think of what these scenarios mean for you and what is worse for you, both financially and emotionally. Then pick the less bad option.

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. . . pick the less bad option.

 

We all need an objective way to make a decision. There are techniques you can use to do that. One simple way is to list a bunch of possible choices on a piece of paper. Then narrow those choices down to the 3 best ones. Put each choice in a column, so that you can compare strengths and weaknesses of each choice, side by side. Then try to quantify best and worst case scenarios.

Of course, time can either be your friend or enemy in this case. And you may have already made your decision by the time this post is made.

If the best answer causes you more short term pain. Then you need a pain management strategy. There is pain that comes from something killing you, or pain that comes from you getting better. Which pain is it? The pain comes from fear. Is it the kind of fear that protects you from danger, or is it the kind of fear that just eats you alive? Fear isn't necessarily bad if it keeps you from taking more risk than you can handle. Is that fear worth fighting, and something you need to work through? Can you conquer it?

If you take the loss, can you make the money back sooner than waiting for the price to come back. I think that is one of the most important questions you need in your list. You must consider "opportunity costs".

 

Opportunity cost - Wikipedia, the free encyclopedia

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catsrevenge,

 

I'm assuming that you normally trade this size so a $28K loss is not out of the ordinary for you when you have a losing trade. I could be wrong. You asked for an opinion, so here's mine. In my opinion, I would hold GE a little longer as it appears to be oversold right now.

 

The first chart shows a volume spike and the second chart shows a b-formation on a market profile chart. Both charts indicate that traders/investors got too short on GE. In addition, you can see excess at the low in the MP chart, which indicates the start of an up auction. I would put my stop just below the recent lows (below the excess), but GE needs to get above 16.37, if it's going higher. If GE pops a little, I would exit as GE trades towards the gap and not be greedy.

 

This is obviously your decision and your trade, but I gave you my opinion anyway. Good luck!

 

GE-spike.GIF.1a64e59b37e07280b2040b8b78604db4.GIF

 

 

GE-b-shape.GIF.44a951c5311c01b746bf7a7d0e81c991.GIF

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Hi catsrevenge

Have a look at the chart dragon 987 posted

Unfortunately I cant see the chart clearly BUT....

The chart shows the price is at support

The long term trend is UP

The candles show consoladation. That means uncertainity.

Which way will it go.?

Set a stop just below these support candles because the price can fall to the GREEN line!

Hold till the price moves back to those flat resistance levels and then sell half.

Then phone for more help

Bob Collett

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Lots of great advice and I imagine you're as confused as ever. Everyone makes good points. Hopefully when all is said and done, you'll learn to make better trade decisions based on a strategy that you have done enough home work on, to have the confidence in knowing that it is effective. No one makes real money on any one trade or another. The real money is made on an edge that your overall trade strategy and 'tradeplan' give you in the market. The problem with fretting a particular trade is that once it is over, as a trader, now you have to take another trade. And another. . etc.. Without a plan, most wind up failing. You're experiencing one reason why, right now, in real time. Get the most value out of this by learning the right lessons. Good education doesn't come cheap. Good luck.

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Hopefully you've got rid of this stock and stopped paying the interest on the margin you took out on it. One thing you should know that is just as important as a trading strategy is that no one and I mean "No One" cares about your money as much as you do. I see that you are taking a really short term approach by your declaration of being so leveraged in this particular case. Maybe try not to go so heavily into your margin and definitely buy on dips. Also, try to stay away from companies right before earnings reports because your'e essentially gambling whether the particular company youv'e chosen has beat expectations. I also think you should not be so invested in one company. I could be totally off base there and you r'e investment account may have many more companies, let me know if I am. GE gives out a decent dividend and companies that do that generally are less volatile. You were looking for volatility by investing short term in them?? Two stocks I would suggest to you and anyone else for that matter would be CHS and MGM. I feel both of those companies price should go up fairly soon. II have a short write-up about CHS on my blog at Wealth Fluctuations. That is all I've got to say about that.

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"No One" cares about your money as much as you do.

 

I wonder if all the OP was simply after a bit of sympathy actually. Or maybe some moral support to do the right (but tough) thing. I guess they have had to sell the computer to make margin as the first post was their one and only post here. (guess you shouldn't joke about other peoples misfortune in a politically correct society).

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I want to thank EVERYONE for their very helpful input ,about my "stuck in a bad position" post here. In general i`d just like to add that, I really didn`t have any so called "plan" that day, when I purchased the 20,000 shares. as a few people had mentioned, but believe me, next time I sure will... , Yes my position was and is short term. I had no intention of holding. What happened that day was, I had already bought and sold 20,000 shares SIX times that day at a profit. Being that for every penny it went up I would make $200 profit, I was riding the crests of the waves all day, and was buying in on dips, and doing very well, about $3650 in profit that day up to that point in time (around 330pm But what happened was that sometime around 330pm, i had just bought in, 20,000 shares at $17.44, and saw it wasn`t really doing much except see-sawing up and down around $17.45 and 17.43.... So I thought maybe I`ll just exit at my cost of $17.44 and call it a day. The door bell rang, and I ran to quickly answer it, when I returned 2 minutes later, the price began dropping $17.45,44,43,42... I thought, let me just hold it overnight and exit in the morning. Well, the next morning due to GE`s negative quarterly earnings report, it plunged to about $16.00. That`s where I became stuck in the position. Otherwise, I probably wouldn`t be. I may add that in the prior two weeks, I had made $13,500 in profits using my short term, quick scalping type strategy. But out of this whole seemingly negative scenario, a lesson or two has been learned. (1) Ignore the doorbell, (2) next time sell even at a loss, at all costs,just to get out, ($200-400-600 loss) in the 330 pm dreaded zone when most day traders mostly dump and exit, so my $3550 profit for the day would have been a little less,but at least i still made money and was home safe. Since Oct 13th I have been holding tight, but lately,I am considering dumping the whole 20,000 shares sometime after the mid term elections, even at a loss, but at least the interest will stop on the margin, which I dipped into, and I will be able to still move forward and profit everyday, once I close my position with GE. Right now this waiting game is like hell, and with my hands tied, each day is a loss. It also seems like every little negative report I hear about every morning, in any economic sector , seems to have its negative repercussion on my bottom line. Thank you all for your help once again, and I wish you all the best of success !

Chris/NJ

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Another way to view the surface energy is to relate it to the work required to cleave a bulk sample, creating two surfaces. If the new surfaces are identical, the surface energy γ of each surface is equal to half the work of cleavage, W: γ = (1/2)W11. If the surfaces are unequal, the Young-Dupré equation applies: W12 = γ1 + γ2 – γ12, where γ1 and γ2 are the surface energies of the two new surfaces, and γ12 is the interfacial energy. This methodology can also be used to discuss cleavage that happens in another medium: γ12 = (1/2)W121 = (1/2)W212. These two energy quantities refer to the energy that is needed to cleave one species into two pieces while it is contained in a medium of the other species. Likewise for a three species system: γ13 + γ23 – γ12 = W12 + W33 – W13 – W23 = W132, where W132 is the energy of cleaving species 1 from species 2 in a medium of species 3.[2] A basic understanding of the terminology of cleavage energy, surface energy, and surface tension is very helpful for understanding the physical state and the events that happen at a given surface, but as discussed below, the theory of these variables also yields some interesting effects that concern the practicality of adhesive surfaces in relation to their surroundings.[2] Mechanisms There is no single theory covering adhesion, and particular mechanisms are specific to particular material scenarios. Five mechanisms of adhesion have been proposed to explain why one material sticks to another: Mechanical Adhesive materials fill the voids or pores of the surfaces and hold surfaces together by interlocking. Other interlocking phenomena are observed on different length scales. Sewing is an example of two materials forming a large scale mechanical bond, velcro forms one on a medium scale, and some textile adhesives (glue) form one at a small scale. Chemical Two materials may form a compound at the joint. The strongest joints are where atoms of the two materials share or swap electrons (known respectively as covalent bonding or ionic bonding). A weaker bond is formed if a hydrogen atom in one molecule is attracted to an atom of nitrogen, oxygen, or fluorine in another molecule, a phenomenon called hydrogen bonding. Chemical adhesion occurs when the surface atoms of two separate surfaces form ionic, covalent, or hydrogen bonds. The engineering principle behind chemical adhesion in this sense is fairly straightforward: if surface molecules can bond, then the surfaces will be bonded together by a network of these bonds. It bears mentioning that these attractive ionic and covalent forces are effective over only very small distances – less than a nanometer. This means in general not only that surfaces with the potential for chemical bonding need to be brought very close together, but also that these bonds are fairly brittle, since the surfaces then need to be kept close together.[3] Dispersive Main article: Dispersive adhesion In dispersive adhesion, also known as physisorption, two materials are held together by van der Waals forces: the attraction between two molecules, each of which has a region of slight positive and negative charge. In the simple case, such molecules are therefore polar with respect to average charge density, although in larger or more complex molecules, there may be multiple "poles" or regions of greater positive or negative charge. These positive and negative poles may be a permanent property of a molecule (Keesom forces) or a transient effect which can occur in any molecule, as the random movement of electrons within the molecules may result in a temporary concentration of electrons in one region (London forces).   Cohesion causes water to form drops, surface tension causes them to be nearly spherical, and adhesion keeps the drops in place.   Water droplets are flatter on a Hibiscus flower which shows better adhesion. In surface science, the term adhesion almost always refers to dispersive adhesion. In a typical solid-liquid-gas system (such as a drop of liquid on a solid surrounded by air) the contact angle is used to evaluate adhesiveness indirectly, while a Centrifugal Adhesion Balance allows for direct quantitative adhesion measurements. Generally, cases where the contact angle is low are considered of higher adhesion per unit area. This approach assumes that the lower contact angle corresponds to a higher surface energy.[4] Theoretically, the more exact relation between contact angle and work of adhesion is more involved and is given by the Young-Dupre equation. The contact angle of the three-phase system is a function not only of dispersive adhesion (interaction between the molecules in the liquid and the molecules in the solid) but also cohesion (interaction between the liquid molecules themselves). Strong adhesion and weak cohesion results in a high degree of wetting, a lyophilic condition with low measured contact angles. Conversely, weak adhesion and strong cohesion results in lyophobic conditions with high measured contact angles and poor wetting. London dispersion forces are particularly useful for the function of adhesive devices, because they don't require either surface to have any permanent polarity. They were described in the 1930s by Fritz London, and have been observed by many researchers. Dispersive forces are a consequence of statistical quantum mechanics. London theorized that attractive forces between molecules that cannot be explained by ionic or covalent interaction can be caused by polar moments within molecules. Multipoles could account for attraction between molecules having permanent multipole moments that participate in electrostatic interaction. However, experimental data showed that many of the compounds observed to experience van der Waals forces had no multipoles at all. London suggested that momentary dipoles are induced purely by virtue of molecules being in proximity to one another. By solving the quantum mechanical system of two electrons as harmonic oscillators at some finite distance from one another, being displaced about their respective rest positions and interacting with each other's fields, London showed that the energy of this system is given by: E=3hν−34hνα2R6{\displaystyle E=3h\nu -{\frac {3}{4}}{\frac {h\nu \alpha ^{2}}{R^{6}}}} While the first term is simply the zero-point energy, the negative second term describes an attractive force between neighboring oscillators. The same argument can also be extended to a large number of coupled oscillators, and thus skirts issues that would negate the large scale attractive effects of permanent dipoles cancelling through symmetry, in particular. The additive nature of the dispersion effect has another useful consequence. Consider a single such dispersive dipole, referred to as the origin dipole. Since any origin dipole is inherently oriented so as to be attracted to the adjacent dipoles it induces, while the other, more distant dipoles are not correlated with the original dipole by any phase relation (thus on average contributing nothing), there is a net attractive force in a bulk of such particles. When considering identical particles, this is called cohesive force.[5] When discussing adhesion, this theory needs to be converted into terms relating to surfaces. If there is a net attractive energy of cohesion in a bulk of similar molecules, then cleaving this bulk to produce two surfaces will yield surfaces with a dispersive surface energy, since the form of the energy remain the same. This theory provides a basis for the existence of van der Waals forces at the surface, which exist between any molecules having electrons. These forces are easily observed through the spontaneous jumping of smooth surfaces into contact. Smooth surfaces of mica, gold, various polymers and solid gelatin solutions do not stay apart when their separating becomes small enough – on the order of 1–10 nm. The equation describing these attractions was predicted in the 1930s by De Boer and Hamaker:[3] Parea=−A24πz3{\displaystyle {\frac {P}{area}}=-{\frac {A}{24\pi z^{3}}}} where P is the force (negative for attraction), z is the separation distance, and A is a material-specific constant called the Hamaker constant.   The two stages of PDMS microstructure collapse due to van der Waals attractions. The PDMS stamp is indicated by the hatched region, and the substrate is indicated by the shaded region. A) The PDMS stamp is placed on a substrate with the "roof" elevated. B) Van der Waals attractions make roof collapse energetically favorable for PDMS stamp. The effect is also apparent in experiments where a polydimethylsiloxane (PDMS) stamp is made with small periodic post structures. The surface with the posts is placed face down on a smooth surface, such that the surface area in between each post is elevated above the smooth surface, like a roof supported by columns. Because of these attractive dispersive forces between the PDMS and the smooth substrate, the elevated surface – or “roof” – collapses down onto the substrate without any external force aside from the van der Waals attraction.[6] Simple smooth polymer surfaces – without any microstructures – are commonly used for these dispersive adhesive properties. Decals and stickers that adhere to glass without using any chemical adhesives are fairly common as toys and decorations and useful as removable labels because they do not rapidly lose their adhesive properties, as do sticky tapes that use adhesive chemical compounds. It is important to note that these forces also act over very small distances – 99% of the work necessary to break van der Waals bonds is done once surfaces are pulled more than a nanometer apart.[3] As a result of this limited motion in both the van der Waals and ionic/covalent bonding situations, practical effectiveness of adhesion due to either or both of these interactions leaves much to be desired. Once a crack is initiated, it propagates easily along the interface because of the brittle nature of the interfacial bonds.[7] As an additional consequence, increasing surface area often does little to enhance the strength of the adhesion in this situation. This follows from the aforementioned crack failure – the stress at the interface is not uniformly distributed, but rather concentrated at the area of failure.[3] Electrostatic Some conducting materials may pass electrons to form a difference in electrical charge at the joint. This results in a structure similar to a capacitor and creates an attractive electrostatic force between the materials. Diffusive Some materials may merge at the joint by diffusion. This may occur when the molecules of both materials are mobile and soluble in each other. This would be particularly effective with polymer chains where one end of the molecule diffuses into the other material. It is also the mechanism involved in sintering. When metal or ceramic powders are pressed together and heated, atoms diffuse from one particle to the next. This joins the particles into one.   The interface is indicated by the dotted line. A) Non-crosslinked polymers are somewhat free to diffuse across the interface. One loop and two distal tails are seen diffusing. B) Crosslinked polymers not free enough to diffuse. C) "Scissed" polymers very free, with many tails extending across the interface. Diffusive forces are somewhat like mechanical tethering at the molecular level. Diffusive bonding occurs when species from one surface penetrate into an adjacent surface while still being bound to the phase of their surface of origin. One instructive example is that of polymer-on-polymer surfaces. Diffusive bonding in polymer-on-polymer surfaces is the result of sections of polymer chains from one surface interdigitating with those of an adjacent surface. The freedom of movement of the polymers has a strong effect on their ability to interdigitate, and hence, on diffusive bonding. For example, cross-linked polymers are less capable of diffusion and interdigitation because they are bonded together at many points of contact, and are not free to twist into the adjacent surface. Uncrosslinked polymers (thermoplastics), on the other hand are freer to wander into the adjacent phase by extending tails and loops across the interface. Another circumstance under which diffusive bonding occurs is “scission”. Chain scission is the cutting up of polymer chains, resulting in a higher concentration of distal tails. The heightened concentration of these chain ends gives rise to a heightened concentration of polymer tails extending across the interface. Scission is easily achieved by ultraviolet irradiation in the presence of oxygen gas, which suggests that adhesive devices employing diffusive bonding actually benefit from prolonged exposure to heat/light and air. The longer such a device is exposed to these conditions, the more tails are scissed and branch out across the interface. Once across the interface, the tails and loops form whatever bonds are favorable. In the case of polymer-on-polymer surfaces, this means more van der Waals forces. While these may be brittle, they are quite strong when a large network of these bonds is formed. The outermost layer of each surface plays a crucial role in the adhesive properties of such interfaces, as even a tiny amount of interdigitation – as little as one or two tails of 1.25 angstrom length – can increase the van der Waals bonds by an order of magnitude.[8] Strength The strength of the adhesion between two materials depends on which of the above mechanisms occur between the two materials, and the surface area over which the two materials contact. Materials that wet against each other tend to have a larger contact area than those that do not. Wetting depends on the surface energy of the materials. Low surface energy materials such as polyethylene, polypropylene, polytetrafluoroethylene and polyoxymethylene are difficult to bond without special surface preparation. Another factor determining the strength of an adhesive contact is its shape. Adhesive contacts of complex shape begin to detach at the "edges" of the contact area[9]. The process of destruction of adhesive contacts can be seen in the film[10]. Other effects In concert with the primary surface forces described above, there are several circumstantial effects in play. While the forces themselves each contribute to the magnitude of the adhesion between the surfaces, the following play a crucial role in the overall strength and reliability of an adhesive device. Stringing   Fingering process. The hatched area is the receiving substrate, the dotted strip is the tape, and the shaded area in between is the adhesive chemical layer. The arrow indicates the direction of propagation for the fracture. Stringing is perhaps the most crucial of these effects, and is often seen on adhesive tapes. Stringing occurs when a separation of two surfaces is beginning and molecules at the interface bridge out across the gap, rather than cracking like the interface itself. The most significant consequence of this effect is the restraint of the crack. By providing the otherwise brittle interfacial bonds with some flexibility, the molecules that are stringing across the gap can stop the crack from propagating.[3] Another way to understand this phenomenon is by comparing it to the stress concentration at the point of failure mentioned earlier. Since the stress is now spread out over some area, the stress at any given point has less of a chance of overwhelming the total adhesive force between the surfaces. If failure does occur at an interface containing a viscoelastic adhesive agent, and a crack does propagate, it happens by a gradual process called “fingering”, rather than a rapid, brittle fracture.[7] Stringing can apply to both the diffusive bonding regime and the chemical bonding regime. The strings of molecules bridging across the gap would either be the molecules that had earlier diffused across the interface or the viscoelastic adhesive, provided that there was a significant volume of it at the interface. Microstructures The interplay of molecular scale mechanisms and hierarchical surface structures is known to result in high levels of static friction and bonding between pairs of surfaces [11]. Technologically advanced adhesive devices sometimes make use of microstructures on surfaces, such as tightly packed periodic posts. These are biomimetic technologies inspired by the adhesive abilities of the feet of various arthropods and vertebrates (most notably, geckos). By intermixing periodic breaks into smooth, adhesive surfaces, the interface acquires valuable crack-arresting properties. Because crack initiation requires much greater stress than does crack propagation, surfaces like these are much harder to separate, as a new crack has to be restarted every time the next individual microstructure is reached.[12] Hysteresis Hysteresis, in this case, refers to the restructuring of the adhesive interface over some period of time, with the result being that the work needed to separate two surfaces is greater than the work that was gained by bringing them together (W > γ1 + γ2). For the most part, this is a phenomenon associated with diffusive bonding. The more time is given for a pair of surfaces exhibiting diffusive bonding to restructure, the more diffusion will occur, the stronger the adhesion will become. The aforementioned reaction of certain polymer-on-polymer surfaces to ultraviolet radiation and oxygen gas is an instance of hysteresis, but it will also happen over time without those factors. In addition to being able to observe hysteresis by determining if W > γ1 + γ2 is true, one can also find evidence of it by performing “stop-start” measurements. In these experiments, two surfaces slide against one another continuously and occasionally stopped for some measured amount of time. Results from experiments on polymer-on-polymer surfaces show that if the stopping time is short enough, resumption of smooth sliding is easy. If, however, the stopping time exceeds some limit, there is an initial increase of resistance to motion, indicating that the stopping time was sufficient for the surfaces to restructure.[8] Wettability and adsorption Some atmospheric effects on the functionality of adhesive devices can be characterized by following the theory of surface energy and interfacial tension. It is known that γ12 = (1/2)W121 = (1/2)W212. If γ12 is high, then each species finds it favorable to cohere while in contact with a foreign species, rather than dissociate and mix with the other. If this is true, then it follows that when the interfacial tension is high, the force of adhesion is weak, since each species does not find it favorable to bond to the other. The interfacial tension of a liquid and a solid is directly related to the liquid's wettability (relative to the solid), and thus one can extrapolate that cohesion increases in non-wetting liquids and decreases in wetting liquids. One example that verifies this is polydimethyl siloxane rubber, which has a work of self-adhesion of 43.6 mJ/m2 in air, 74 mJ/m2 in water (a nonwetting liquid) and 6 mJ/m2 in methanol (a wetting liquid). This argument can be extended to the idea that when a surface is in a medium with which binding is favorable, it will be less likely to adhere to another surface, since the medium is taking up the potential sites on the surface that would otherwise be available to adhere to another surface. Naturally this applies very strongly to wetting liquids, but also to gas molecules that could adsorb onto the surface in question, thereby occupying potential adhesion sites. This last point is actually fairly intuitive: Leaving an adhesive exposed to air too long gets it dirty, and its adhesive strength will decrease. This is observed in the experiment: when mica is cleaved in air, its cleavage energy, W121 or Wmica/air/mica, is smaller than the cleavage energy in vacuum, Wmica/vac/mica, by a factor of 13.[3] Lateral adhesion Lateral adhesion is the adhesion associated with sliding one object on a substrate such as sliding a drop on a surface. When the two objects are solids, either with or without a liquid between them, the lateral adhesion is described as friction. However, the behavior of lateral adhesion between a drop and a surface is tribologically very different from friction between solids, and the naturally adhesive contact between a flat surface and a liquid drop makes the lateral adhesion in this case, an individual field. Lateral adhesion can be measured using the centrifugal adhesion balance (CAB),[13][14] which uses a combination of centrifugal and gravitational forces to decouple the normal and lateral forces in the problem. See also Adhesive Adhesive bonding Bacterial adhesin Capillary action Cell adhesion Contact mechanics Fracture mechanics Galling Insect adhesion Meniscus Mucoadhesion Pressure-sensitive adhesive Rail adhesion Synthetic setae Cohesion number References   Vert, Michel; Doi, Yoshiharu; Hellwich, Karl-Heinz; Hess, Michael; Hodge, Philip; Kubisa, Przemyslaw; Rinaudo, Marguerite; Schué, François (2012). "Terminology for biorelated polymers and applications (IUPAC Recommendations 2012)" (PDF). Pure and Applied Chemistry. 84 (2): 377–410. doi:10.1351/PAC-REC-10-12-04.   J. N. Israelachvili, Intermolecular and Surface Forces (Academic Press, New York, 1985). chap. 15.   K. Kendall (1994). "Adhesion: Molecules and Mechanics". Science. 263 (5154): 1720–5. doi:10.1126/science.263.5154.1720. PMID 17795378.   Laurén, Susanna. "What is required for good adhesion?". blog.biolinscientific.com. Retrieved 2019-12-31.   F. London, "The General Theory of Molecular Forces" (1936).   Y. Y. Huang; Zhou, Weixing; Hsia, K. J.; Menard, Etienne; Park, Jang-Ung; Rogers, John A.; Alleyne, Andrew G. (2005). "Stamp Collapse in Soft Lithography" (PDF). Langmuir. 21 (17): 8058–68. doi:10.1021/la0502185. PMID 16089420.   Bi-min Zhang Newby, Manoj K. Chaudhury and Hugh R. Brown (1995). "Macroscopic Evidence of the Effect of Interfacial Slippage on Adhesion" (PDF). Science. 269 (5229): 1407–9. doi:10.1126/science.269.5229.1407. PMID 17731150.   N. Maeda; Chen, N; Tirrell, M; Israelachvili, JN (2002). "Adhesion and Friction Mechanisms of Polymer-on-Polymer Surfaces". Science. 297 (5580): 379–82. doi:10.1126/science.1072378. PMID 12130780.   Popov, Valentin L.; Pohrt, Roman; Li, Qiang (2017-09-01). "Strength of adhesive contacts: Influence of contact geometry and material gradients". Friction. 5 (3): 308–325. doi:10.1007/s40544-017-0177-3. ISSN 2223-7690.   Friction Physics (2017-12-06), Science friction: Adhesion of complex shapes, retrieved 2017-12-30   Static Friction at Fractal Interfaces Tribology International 2016, Volume 93   A. Majmuder; Ghatak, A.; Sharma, A. (2007). "Microfluidic Adhesion Induced by Subsurface Microstructures". Science. 318 (5848): 258–61. doi:10.1126/science.1145839. PMID 17932295.   Tadmor, Rafael (2009). "Measurement of Lateral Adhesion Forces at the Interface between a Liquid Drop and a Substrate". Physical Review Letters. 103 (26): 266101. doi:10.1103/physrevlett.103.266101. PMID 20366322.   Tadmor, Rafael; Das, Ratul; Gulec, Semih; Liu, Jie; E. N’guessan, Hartmann; Shah, Meet; S. Wasnik, Priyanka; Yadav, Sakshi B. (2017-04-18). "Solid–Liquid Work of Adhesion". Langmuir. 33 (15): 3594–3600. doi:10.1021/acs.langmuir.6b04437. ISSN 0743-7463. PMID 28121158. Further reading
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