Rice bran fatty alkanol agricultural microemulsion and preparation method thereof

Abstract

The invention provides a rice bran fatty alkanol agricultural microemulsion which comprises the following raw materials in percentage by weight: 0.001%-0.1% of rice bran fatty alkanol, 0.001%-0.2% of a main emulsifier, 0.001%-2% of a co-emulsifier, 0.1%-2% of ethanol and the balance of water, under heating and stirring conditions, dissolving rice bran fatty alkanol in a co-emulsifier to obtain a rice bran fatty alkanol mixed solution; dissolving a main emulsifier in ethanol to obtain a main emulsifier mixed solution; and adding the main emulsifier mixed solution into the rice bran fatty alkanol mixed solution, reacting, adding water after a reactant is clarified and transparent, carrying out heat preservation stirring, and cooling to obtain the rice bran fatty alkanol agricultural microemulsion. Compared with the prior art, the preparation method has the advantages of simple process flow, no need of high-pressure homogenization equipment and the like, immediate preparation during use, and effective avoiding of the problems of particle size change, layering and precipitation during long-term storage of the microemulsion.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural production and relates to a method for preparing a rice bran fatty alkanol agricultural microemulsion. Background Art

[0002] Rice bran fatty alkanol is a high-grade fatty alkanol mixture made from rice bran wax by saponification, extraction, filtration and other processes. Its main components are octacosanol, triacontanol and dotriacontanol. Triacontanol was discovered by American biologist Chibnall and others from alfalfa as early as 1933. In 1975, Professor Ries and other personnel from Michigan State University in the United States conducted further research. The test results showed that crop yield increased by 58% to 68%, proving that triacontanol not only has a regulating and promoting effect on plant growth, but also has a yield-increasing effect. Subsequent studies have shown that triacontanol is an endogenous plant growth regulator with multiple physiological functions such as increasing polyphenol oxidase activity, increasing chlorophyll content, and enhancing photosynthesis. It has a significant yield-increasing effect on rice, wheat, corn and other plants. As a non-toxic and pollution-free natural plant growth regulator, triacontanol meets the requirements of modern agriculture for environmental protection and sustainable development. Therefore, it is favored by more and more farmers and agricultural enterprises, and the market demand continues to grow.

[0003] However, since the carbon chain number of rice bran fatty alkanol is more than 22, this special long-chain structure leads to poor hydrophilicity and its solubility in water is less than 9×10 -14 g / L, and is only soluble in some organic solvents, which greatly limits its wide and safe application in the agricultural field. As a new type of pesticide formulation, microemulsion has the advantages of environmental friendliness, high stability, high solubilization, and high transfer efficiency, showing great application potential in modern agricultural production.

[0004] The effective concentration of triacontanol when used on plants is extremely low. The recommended concentration for spraying on fruit and oil crops is 1.0-2.0 mg / L. Too high a concentration will inhibit plant growth. However, the effective content of triacontanol products on the market is generally 0.1% (1000 mg / L), and it needs to be diluted for use. Therefore, the storage stability and dilution stability of the product are extremely important.

[0005] "N-triacontanol microemulsion and its production process" (CN1395830A) uses a one-step direct emulsification method to prepare triacontanol into a microemulsion, but this method has the following disadvantages: first, the above process requires the use of a large amount of organic solvent to ensure that triacontanol is evenly dispersed. Under the condition of a lower dosage of organic solvent, the prepared microemulsion effect is very unstable, and it is easy to produce an apparently turbid and opaque product; secondly, the emission of volatile organic compounds (VOCs) is now an important environmental issue, and the country is paying more and more attention to this issue. The ethanol residue in the microemulsion product is relatively large, and VOCs pollution will also be generated when it is used, which does not conform to the trend of modern green and environmentally friendly pesticides. "A rice bran fatty alkanol aqueous solution and preparation method" (CN 113197977 A) uses a two-step emulsification method to prepare rice bran fatty alkanol into an aqueous solution, but this method has the following disadvantages: first, the hydrophilic-lipophilic balance value HLB of Tween 80 is only 15, and the emulsification ability is poor. The emulsion prepared by using Tween 80 as a single emulsifier has a particle size greater than 100 nanometers, which does not meet the definition of a microemulsion; secondly, the emulsion system can only exist stably when it contains a specific content of water, and cannot be diluted with water at will according to actual needs. When diluted with water, particles will aggregate and precipitate, affecting the actual use effect.

[0006] In summary, in the prior art, high-pressure homogenization and emulsification are often required to prepare microemulsions to improve their storage stability, and the process is relatively complicated. However, microemulsions will still face problems such as particle size change and stratification precipitation after long-term storage, which seriously affects their use effect. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a rice bran fatty alkanol agricultural microemulsion and a preparation method thereof, and provides a method for preparing a triacontanol microemulsion with a simple process and easy operation. The microemulsion can be prepared immediately when in use, and there is no need to worry about the problem of unstable efficacy caused by long-term storage of the microemulsion.

[0008] The present invention is achieved through the following technical solutions:

[0009] A rice bran fatty alkanol agricultural microemulsion, wherein the components, by mass percentage, include:

[0010] Rice bran fatty alkyl alcohol 0.001%~0.1%,

[0011] Main emulsifier 0.001%~0.2%,

[0012] Emulsifier 0.001%~2%,

[0013] Ethanol 0.1% to 10%,

[0014] The balance is water.

[0015] A method for preparing a rice bran fatty alkanol agricultural microemulsion, comprising:

[0016] S1. According to the percentage of each component, obtain a raw material of 0.001% to 0.1% of rice bran fatty alkanol, 0.001% to 0.2% of a primary emulsifier, 0.001% to 2% of a co-emulsifier, 0.1% to 2% of ethanol, and the balance being water;

[0017] S2, under heating and stirring conditions, dissolving rice bran fatty alkanol in a co-emulsifier to obtain a rice bran fatty alkanol mixed solution; dissolving a primary emulsifier in ethanol to obtain a primary emulsifier mixed solution;

[0018] S3, adding the main emulsifier mixed solution into the rice bran fatty alkanol mixed solution, after the reaction, adding hot water after the reactant becomes clear, keeping warm and stirring, and cooling to obtain the rice bran fatty alkanol agricultural microemulsion.

[0019] Preferably, the primary emulsifier is sodium lauryl sulfate.

[0020] Preferably, the auxiliary emulsifier is one of fatty alcohol polyoxyethylene ether and a mixture of fatty alcohol polyoxyethylene ether and Tween 80.

[0021] Preferably, the heating and stirring conditions of S2 are: a temperature of 55-75° C. and a stirring rate of 100 r / min.

[0022] Preferably, the reaction conditions of adding the primary emulsifier mixed solution in S3 to the rice bran fatty alkanol mixed solution are: reacting at 60-100° C. for 0.5-2 h.

[0023] Preferably, the time of heat preservation and stirring in S3 is 0.5-2h, and the temperature of the hot water is 80-95°C.

[0024] Preferably, the particle size distribution of the rice bran fatty alkanol agricultural microemulsion is 10 to 80 nm.

[0025] Compared with the prior art, the present invention has the following beneficial technical effects:

[0026] The invention provides a rice bran fatty alkanol agricultural microemulsion and a preparation method thereof. The components, by mass percentage, include 0.001% to 0.1% of rice bran fatty alkanol, 0.001% to 0.2% of a primary emulsifier, 0.001% to 2% of an auxiliary emulsifier, 0.1% to 10% of ethanol, and the balance is water. A method for preparing a triacontanol microemulsion with a simple process and simple operation is provided. The microemulsion is prepared immediately when in use, and there is no need to worry about the problem of unstable efficacy of the microemulsion due to long-term storage. The invention overcomes the shortcomings of the prior art, has a simple process flow, does not require high-pressure homogenization and other equipment, can prepare a rice bran fatty alkanol microemulsion with an apparent clear and transparent appearance and a particle size distribution of 10 to 80 nm, and solves the problems of large ethanol usage, excessive emulsion particle size, unstable effect, etc. in the current preparation technology. Compared with the prior art, the invention has a simple process flow, does not require high-pressure homogenization and other equipment, is prepared immediately when in use, and effectively avoids the problem of particle size change and stratification precipitation faced by the microemulsion in long-term storage.

[0027] Furthermore, compared with the prior art, the present invention adopts the method of dissolving and dispersing rice bran fatty alkanol in two steps, so that the rice bran fatty alkanol is dispersed more evenly, and the prepared microemulsion has an apparent clarity and a particle size of 10 to 80 nm, which effectively solves the problem of excessively large microemulsion particle size caused by uneven dispersion in the one-step emulsification method.

[0028] Furthermore, compared with the one-step emulsification technology used in the preparation method of the prior art, the two-step emulsification method of the present invention can effectively reduce the amount of ethanol used in the production process, and the overall process is more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the appearance of the two-step microemulsion;

[0030] Figure 2 The particle size analysis results of Example 1 are shown below:

[0031] Figure 3 The particle size analysis results of Example 2 are shown below:

[0032] Figure 4 The particle size analysis results of Example 3 are shown below:

[0033] Figure 5 The particle size analysis results of Example 4 are shown below:

[0034] Figure 6 This is the particle size analysis result of Example 5. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0036] The technical solution adopted by the present invention is: a two-step method for preparing rice bran fatty alkanol agricultural microemulsion, and the specific preparation method comprises:

[0037] (1) Prepare the raw materials according to the following formula in mass percentage:

[0038] Rice bran fatty alkyl alcohol 0.001~0.1%,

[0039] Main emulsifier 0.001~0.2%,

[0040] Emulsifier 0.001~2%,

[0041] Ethanol 0.1~10%,

[0042] Water Residue,

[0043] The above components total 100%;

[0044] (2) primary dispersion: dissolving rice bran fatty alkanol in an auxiliary emulsifier at 55-75° C. and a stirring rate of 100 r / min to obtain a rice bran fatty alkanol mixed solution; dissolving a primary emulsifier, sodium lauryl sulfate, in ethanol to obtain a primary emulsifier mixed solution;

[0045] (3) secondary dispersion: adding the primary emulsifier mixed solution of step (1) to the rice bran fatty alkanol mixed solution, and reacting at 60-100° C. for 0.5-2 h;

[0046] (4) Stirring and emulsifying: After the rice bran fatty alkanol mixed solution becomes clear and transparent, add hot water at 80-95°C, keep warm and stir for 0.5-2h, and cool naturally to obtain the rice bran fatty alkanol agricultural microemulsion, such as Figure 1 As shown;

[0047] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0048] Embodiment 1:

[0049] The preparation method of rice bran fatty alkanol agricultural microemulsion is as follows:

[0050] (1) Prepare the raw materials according to the following formula in mass percentage:

[0051] Rice bran fatty alkyl alcohol 0.1%,

[0052] Sodium dodecyl sulfate 0.1%,

[0053] Fatty alcohol polyoxyethylene ether 1.2%,

[0054] Ethanol 1%,

[0055] The balance is water;

[0056] The above components total 100%;

[0057] (2) primary dispersion: dissolving rice bran fatty alkanol in auxiliary emulsifier (fatty alcohol polyoxyethylene ether) to obtain a rice bran fatty alkanol mixed solution under heating and stirring at a temperature of 60° C. and a stirring rate of 100 r / min; dissolving a primary emulsifier (sodium lauryl sulfate) in ethanol to obtain a primary emulsifier mixed solution;

[0058] (3) Secondary dispersion: adding the primary emulsifier mixed solution of step (1) into the rice bran fatty alkanol mixed solution, and reacting at 80° C. for 0.5 h;

[0059] (4) stirring and emulsifying: after the rice bran fatty alkanol mixed solution becomes clear and transparent, add hot water at 85° C., keep warm and stir for 1 hour, and cool naturally to obtain the rice bran fatty alkanol agricultural microemulsion;

[0060] Example 1 The rice bran fatty alkanol agricultural microemulsion prepared was clear and transparent, with a mass proportion of triacontanol of 0.1%, which was equivalent to the content of commercially available products. The average particle size was 73.13 nm as measured by a Malvern particle size analyzer, and the particle size distribution results were as follows: Figure 2 As shown, the three lines in the figure represent three repeated experiments, and the average of the three repeated experiments on the sample was taken. After the microemulsion was centrifuged at 4000r / min for 15min, there was no apparent stratification phenomenon and no precipitation at the bottom.

[0061] Embodiment 2:

[0062] The preparation method of rice bran fatty alkanol agricultural microemulsion is as follows:

[0063] (1) Prepare the raw materials according to the following formula in mass percentage:

[0064] Rice bran fatty alkyl alcohol 0.01%,

[0065] Sodium dodecyl sulfate 0.01%,

[0066] Fatty alcohol polyoxyethylene ether 0.1%,

[0067] Tween 80 0.02%,

[0068] Ethanol 1%,

[0069] The balance is water;

[0070] The above components total 100%;

[0071] (2) primary dispersion: dissolving rice bran fatty alkanol in a mixed auxiliary emulsifier (fatty alcohol polyoxyethylene ether and Tween 80) under heating and stirring conditions at a temperature of 55° C. and a stirring rate of 100 r / min to obtain a rice bran fatty alkanol mixed solution; dissolving a primary emulsifier, sodium lauryl sulfate, in ethanol to obtain a primary emulsifier mixed solution;

[0072] (3) Secondary dispersion: adding the primary emulsifier mixed solution of step (1) into the rice bran fatty alkanol mixed solution, and reacting at 75° C. for 0.5 h;

[0073] (4) stirring and emulsifying: after the rice bran fatty alkanol mixed solution becomes clear and transparent, add 80° C. hot water, keep warm and stir for 0.5 h, and cool naturally to obtain the rice bran fatty alkanol agricultural microemulsion;

[0074] Example 2 The rice bran fatty alkanol agricultural microemulsion prepared was clear and transparent, with a mass proportion of triacontanol of 0.006%. The average particle size was 18.29 nm as measured by a Malvern particle size analyzer. The particle size distribution results were as follows: Figure 3 As shown, the three lines in the figure represent three repeated experiments, and the average of the three repeated experiments on the sample is taken. After the microemulsion was centrifuged at 4000r / min for 15min, there was no apparent stratification phenomenon and no precipitation at the bottom.

[0075] Embodiment 3:

[0076] The preparation method of rice bran fatty alkanol agricultural microemulsion is as follows:

[0077] (1) Prepare the raw materials according to the following formula in mass percentage:

[0078] Rice bran fatty alkyl alcohol 0.1%,

[0079] Sodium dodecyl sulfate 0.1%,

[0080] Fatty alcohol polyoxyethylene ether 1%,

[0081] Ethanol 5%,

[0082] Water Residue,

[0083] The above components total 100%;

[0084] (2) Dispersing and dissolving: directly dissolving rice bran fatty alkyl alcohol, sodium lauryl sulfate and fatty alcohol polyoxyethylene ether in ethanol under heating and stirring conditions of 75° C. and 100 r / min;

[0085] (3) stirring and emulsifying: after the rice bran fatty alkanol is evenly dispersed, add 95° C. hot water, keep warm and stir for 1 hour, and cool naturally to obtain the rice bran fatty alkanol agricultural microemulsion;

[0086] Example 3 The rice bran fatty alkanol agricultural microemulsion prepared was clear and transparent, with an effective content of triacontanol of 0.1%. The average particle size was 288.50 nm as measured by a Malvern particle size analyzer. The particle size distribution results were as follows: Figure 4 As shown, the three lines in the figure represent three repeated experiments, and the average of the three repeated experiments on the sample is taken. After the microemulsion was centrifuged at 4000r / min for 15min, there was no apparent stratification phenomenon, and there were trace needle-shaped crystals at the bottom.

[0087] Embodiment 4:

[0088] The preparation method of rice bran fatty alkanol agricultural microemulsion is as follows:

[0089] (1) Prepare the raw materials according to the following formula in mass percentage:

[0090] Rice bran fatty alkyl alcohol 0.1%,

[0091] Sodium dodecyl sulfate 0.1%,

[0092] Fatty alcohol polyoxyethylene ether 1%,

[0093] Ethanol 10%,

[0094] Water Residue,

[0095] The above components total 100%;

[0096] (2) Dispersing and dissolving: directly dissolving rice bran fatty alkyl alcohol, sodium lauryl sulfate and fatty alcohol polyoxyethylene ether in ethanol under heating and stirring conditions of 65° C. and 100 r / min;

[0097] (3) stirring and emulsifying: after the rice bran fatty alkanol is evenly dispersed, add 90° C. hot water, keep warm and stir for 1 hour, and cool naturally to obtain the rice bran fatty alkanol agricultural microemulsion;

[0098] Example 4 The rice bran fatty alkanol agricultural microemulsion prepared was clear and transparent, with an effective content of triacontanol of 0.1%. The average particle size was 223.60 nm as measured by a Malvern particle size analyzer. The particle size distribution results were as follows: Figure 5 As shown, the three lines in the figure represent three repeated experiments, and the average of the three repeated experiments on the sample is taken. After the microemulsion was centrifuged at 4000r / min for 15min, there was no apparent stratification phenomenon, and there were trace needle-shaped crystals at the bottom.

[0099] Comparison of the particle size analysis results (73.13 nm, 288.50 nm, 223.60 nm) of Example 1 and Examples 3-4 shows that the microemulsion prepared by the two-step method is significantly improved.

[0100] Example 5: The samples in Example 1 were used for storage experiment. The experimental conditions were as follows: sealed and stored at room temperature away from light for 8 months.

[0101] The microemulsion of Example 5 is clear and transparent. The average particle size is 196.40 nm as measured by Malvern particle size analyzer. The particle size distribution is as follows: Figure 6 As shown, the three lines in the figure represent three repeated experiments, and the average of the three repeated experiments on the sample is taken. After the microemulsion was centrifuged at 4000r / min for 15min, there was no apparent stratification phenomenon and no precipitation at the bottom.

[0102] Comparison of the particle size analysis results of Example 1 and Example 5 (73.13 nm, 196.40 nm) shows that the particle size of the microemulsion increases with the storage time. The problem of particle size increase caused by storage can be effectively solved by preparing the microemulsion before use.

[0103] Comparative Example 1

[0104] The preparation method of rice bran fatty alkanol agricultural microemulsion is as follows:

[0105] (1) Prepare the raw materials according to the following formula:

[0106] Rice bran fatty alkyl alcohol 0.1%,

[0107] Sodium dodecyl sulfate 0.1%,

[0108] Fatty alcohol polyoxyethylene ether 1.2%,

[0109] Ethanol 5%,

[0110] The balance is water;

[0111] The above components total 100%;

[0112] (2) primary dispersion: dissolving rice bran fatty alkanol in auxiliary emulsifier (fatty alcohol polyoxyethylene ether) to obtain a rice bran fatty alkanol mixed solution under heating and stirring at a temperature of 60° C. and a stirring rate of 100 r / min; dissolving a primary emulsifier (sodium lauryl sulfate) in ethanol to obtain a primary emulsifier mixed solution;

[0113] (3) Secondary dispersion: adding the primary emulsifier mixed solution of step (1) into the rice bran fatty alkanol mixed solution, and reacting at 80° C. for 0.5 h;

[0114] (4) stirring and emulsifying: after the rice bran fatty alkanol mixed solution becomes clear and transparent, add hot water at 85° C., keep warm and stir for 1 hour, and cool naturally to obtain the rice bran fatty alkanol agricultural microemulsion;

[0115] Comparative Example 2

[0116] The preparation method of rice bran fatty alkanol agricultural microemulsion is as follows:

[0117] (1) Prepare the raw materials according to the following formula:

[0118] Rice bran fatty alkyl alcohol 0.1%,

[0119] Sodium dodecyl sulfate 0.1%,

[0120] Fatty alcohol polyoxyethylene ether 1.2%,

[0121] Ethanol 10%,

[0122] The balance is water;

[0123] The above components total 100%;

[0124] (2) primary dispersion: dissolving rice bran fatty alkanol in auxiliary emulsifier (fatty alcohol polyoxyethylene ether) to obtain a rice bran fatty alkanol mixed solution under heating and stirring at a temperature of 60° C. and a stirring rate of 100 r / min; dissolving a primary emulsifier (sodium lauryl sulfate) in ethanol to obtain a primary emulsifier mixed solution;

[0125] (3) Secondary dispersion: adding the primary emulsifier mixed solution of step (1) into the rice bran fatty alkanol mixed solution, and reacting at 80° C. for 0.5 h;

[0126] (4) stirring and emulsifying: after the rice bran fatty alkanol mixed solution becomes clear and transparent, add hot water at 85° C., keep warm and stir for 1 hour, and cool naturally to obtain the rice bran fatty alkanol agricultural microemulsion;

[0127] Comparing the ethanol dosage (1%, 5%, 10%) of Example 1 and Comparative Examples 1-2, the ethanol dosage of the two-step method is significantly reduced, and the particle size result is significantly reduced. Increasing the ethanol dosage in Comparative Example 2 can reduce the particle size of the microemulsion product to a certain extent.

[0128] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0129] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the drawings and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A rice bran fatty alkanol agricultural microemulsion, characterized in that: The components are calculated by weight percentage, including: Rice bran fatty alkyl alcohol 0.001%~0.1%, Main emulsifier 0.001%~0.2%, Emulsifier 0.001%~2%, Ethanol 0.1% to 10%, The balance is water.

2. The method for preparing a rice bran fatty alkanol agricultural microemulsion as claimed in claim 1, characterized in that: include, S1. According to the mass percentage of each component, obtain a raw material of 0.001% to 0.1% of rice bran fatty alkanol, 0.001% to 0.2% of a primary emulsifier, 0.001% to 2% of a co-emulsifier, 0.1% to 2% of ethanol, and the balance being water; S2, under heating and stirring conditions, dissolving rice bran fatty alkanol in a co-emulsifier to obtain a rice bran fatty alkanol mixed solution; dissolving a primary emulsifier in ethanol to obtain a primary emulsifier mixed solution; S3, adding the main emulsifier mixed solution into the rice bran fatty alkanol mixed solution, after the reaction, adding hot water after the reactant becomes clear, keeping warm and stirring, and cooling to obtain the rice bran fatty alkanol agricultural microemulsion.

3. The method for preparing a rice bran fatty alkanol agricultural microemulsion according to claim 2, characterized in that: The primary emulsifier is sodium lauryl sulfate.

4. The method for preparing a rice bran fatty alkanol agricultural microemulsion according to claim 2, characterized in that: The auxiliary emulsifier is one of fatty alcohol polyoxyethylene ether and a mixture of fatty alcohol polyoxyethylene ether and Tween 80.

5. The method for preparing a rice bran fatty alkanol agricultural microemulsion according to claim 2, characterized in that: The heating and stirring conditions of S2 are: a temperature of 55-75° C. and a stirring rate of 100 r / min.

6. The method for preparing a rice bran fatty alkanol agricultural microemulsion according to claim 2, characterized in that: The main emulsifier mixed solution in S3 is added to the rice bran fatty alkanol mixed solution under the reaction conditions of: reacting at 60-100° C. for 0.5-2h.

7. The method for preparing a rice bran fatty alkanol agricultural microemulsion according to claim 2, characterized in that: The time of heat preservation and stirring in S3 is 0.5-2h, and the temperature of hot water is 80-95°C.

8. The method for preparing a rice bran fatty alkanol agricultural microemulsion according to claim 2, characterized in that: The particle size distribution of the rice bran fatty alkanol agricultural microemulsion is 10-80nm.

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