May 2, 2011 – Surfactants 101
QUESTION:
What is the difference between non-ionic sticker and liquid dish soap?
ANSWER:
I am not a chemist, and pretty much hated chemistry in college, so it can be confusing to me too to get too technical on this. But, basically a liquid dish soap is a wetting agent..........period. The definition I could find all over the internet is that a Surfactant is something which breaks down the surface tension of water to allow things to get wetter, and thus makes it easier to remove dirt, grease, etc. and keeps these materials suspended in the water so that it can be rinsed and removed. If you put a drop of water on a leaf it would ball up to create that bulbous drop just sitting there. This is because water molecules cling together and keep them as that drop. This is the reason bugs like water striders are able to skate across the top of the water rather than sinking. They are standing on molecules of water that are connected to each other.
For our purposes in using pesticides, particularly herbicides, Surfactant means "surface active agent", and we tend to lump several other kinds of materials into it. This includes Spreaders, Stickers, Penetrants, Buffers, etc., and each of these really does do something different on the surface of the plant. Some are self explanatory - penetrants help move the active ingredient into the plant by breaking down the waxy coating on some foliage, spreaders help break down the surface tension of the water so that the spray droplets flatten out and cover more of the leaf, buffers lower the pH of the water so that it is more acidic, which helps to lessen the destruction of the pesticide molecule. Another term used for all of these is "Adjuvants", and maybe this is the better word to use, since it refers to things we add to the spray solution to enhance it in some way.
Stickers are just that - they are surfactants that assist in keeping the spray and the active ingredient on the foliage so that it is retained longer and can have a longer time to kill bugs or affect the weed. Dish soap really is not a sticker, so if a sticker is called for or desirable then a commercial product labeled as such should be used. Some of the commercial products combine the substances. For example No Foam A is a Spreader-Activator, No Foam B is a Spreader-Activator-Buffer, EcoAdjuvant is a Spreader-Emulsifier.
It is important to read all that fine print on product labels, and some may recommend the use of one or another kind of spray adjuvant. Spreaders are particularly important for weed control, as many weeds have very hairy stems or leaves, and a spreader (including liquid soap I suppose) would help break down the water surface tension to get the spray solution onto the foliage itself. If drift is a concern you should consider adding a drift retardant that minimizes the fine particles most likely to be carried off site. If the water in your area is high in pH then a buffer would be a good idea, especially with insecticides. It also would be very advisable to use a product actually formulated for use with pesticides, rather than dish soap which is intended for a very different use, and some state regulatory agencies might even frown on the use of liquid soap being used as an additive to a pesticide spray solution.
Oops, almost forgot the part about "non-ionic". Here are the basics, but don't get confused. Ionic refers to something with an electrical charge to it, either a positive charge (cationic) or a negative charge (anionic), and this can have an effect on the herbicide you use. Soap is apparently anionic, and thus has a negative charge to it, and anionic materials do not like "hard" water - water with a high mineral content and thus are alkaline. If the herbicide you use tells you to add a Non-ionic surfactant (one that is neither positive nor negative) then liquid soap should NOT be used. It may also have something to do with the natural electrical properties of the surface of weeds, whereby using the wrong surfactant could prevent the herbicide from sticking to the foliage or getting into the tissues.
What is the difference between non-ionic sticker and liquid dish soap?
ANSWER:
I am not a chemist, and pretty much hated chemistry in college, so it can be confusing to me too to get too technical on this. But, basically a liquid dish soap is a wetting agent..........period. The definition I could find all over the internet is that a Surfactant is something which breaks down the surface tension of water to allow things to get wetter, and thus makes it easier to remove dirt, grease, etc. and keeps these materials suspended in the water so that it can be rinsed and removed. If you put a drop of water on a leaf it would ball up to create that bulbous drop just sitting there. This is because water molecules cling together and keep them as that drop. This is the reason bugs like water striders are able to skate across the top of the water rather than sinking. They are standing on molecules of water that are connected to each other.
For our purposes in using pesticides, particularly herbicides, Surfactant means "surface active agent", and we tend to lump several other kinds of materials into it. This includes Spreaders, Stickers, Penetrants, Buffers, etc., and each of these really does do something different on the surface of the plant. Some are self explanatory - penetrants help move the active ingredient into the plant by breaking down the waxy coating on some foliage, spreaders help break down the surface tension of the water so that the spray droplets flatten out and cover more of the leaf, buffers lower the pH of the water so that it is more acidic, which helps to lessen the destruction of the pesticide molecule. Another term used for all of these is "Adjuvants", and maybe this is the better word to use, since it refers to things we add to the spray solution to enhance it in some way.
Stickers are just that - they are surfactants that assist in keeping the spray and the active ingredient on the foliage so that it is retained longer and can have a longer time to kill bugs or affect the weed. Dish soap really is not a sticker, so if a sticker is called for or desirable then a commercial product labeled as such should be used. Some of the commercial products combine the substances. For example No Foam A is a Spreader-Activator, No Foam B is a Spreader-Activator-Buffer, EcoAdjuvant is a Spreader-Emulsifier.
It is important to read all that fine print on product labels, and some may recommend the use of one or another kind of spray adjuvant. Spreaders are particularly important for weed control, as many weeds have very hairy stems or leaves, and a spreader (including liquid soap I suppose) would help break down the water surface tension to get the spray solution onto the foliage itself. If drift is a concern you should consider adding a drift retardant that minimizes the fine particles most likely to be carried off site. If the water in your area is high in pH then a buffer would be a good idea, especially with insecticides. It also would be very advisable to use a product actually formulated for use with pesticides, rather than dish soap which is intended for a very different use, and some state regulatory agencies might even frown on the use of liquid soap being used as an additive to a pesticide spray solution.
Oops, almost forgot the part about "non-ionic". Here are the basics, but don't get confused. Ionic refers to something with an electrical charge to it, either a positive charge (cationic) or a negative charge (anionic), and this can have an effect on the herbicide you use. Soap is apparently anionic, and thus has a negative charge to it, and anionic materials do not like "hard" water - water with a high mineral content and thus are alkaline. If the herbicide you use tells you to add a Non-ionic surfactant (one that is neither positive nor negative) then liquid soap should NOT be used. It may also have something to do with the natural electrical properties of the surface of weeds, whereby using the wrong surfactant could prevent the herbicide from sticking to the foliage or getting into the tissues.
