Use of a self-supporting liquid crystal in the electrically regulated transport of ions

Abstract

The application discloses application of a self-supporting liquid crystal in electrically-regulated ion transmission. In the application, the liquid crystal with a specific structure is used in electrically-regulated ion transmission, the size of a transmembrane current can be effectively regulated by a voltage applied thereon, and the self-supporting liquid crystal is simple in preparation method, low in cost and suitable for large-scale preparation.

Description

Technical Field

[0001] This invention relates to the field of smart polymer materials energy. More specifically, it relates to the application of a self-supporting liquid crystal in electro-regulated ion transport. Background Technology

[0002] Biological nanochannels can open or close in response to environmental stimuli, playing a crucial role in normal cellular and biological processes. Biological nanochannels possess three basic transport functions: ion selectivity, ion rectification, and ion gating. For example, OmpF porin in Gram-negative bacteria integrates these three basic ion transport functions, enabling it to protect cells from damage caused by changes in external acid-base environments. Most nanochannels in organisms are phospholipid molecular layers that are easily affected by external environments and have poor stability. Therefore, scientists use functional materials to construct biomimetic artificial nanochannels. For example, cone-shaped nanochannels can be etched onto a polyethylene terephthalate substrate, and the surface of the nanochannels can be modified with charged responsive functional molecules or block copolymers to achieve pH, light, and temperature-responsive nanochannels. However, the mechanical properties of these materials are poor, making large-area fabrication impossible. Therefore, finding novel materials to construct nanochannels is urgent and necessary. Summary of the Invention

[0003] Based on the above facts, the purpose of this invention is to provide an application of self-supporting liquid crystal in electro-controlled ion transport.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] An application of a self-supporting liquid crystal in electro-controlled ion transport.

[0006] Furthermore, the phase state of the self-supporting liquid crystal is a smectic phase or a nematic phase, and the layers of the self-supporting liquid crystal contain two-dimensional oriented nanochannels that are positively charged under acidic conditions and negatively charged under alkaline conditions.

[0007] This technical solution is the first to use self-supporting liquid crystal in electrically regulated ion transport, achieving good results. The phase state of the self-supporting liquid crystal also affects its application effect in electrically regulated ion transport. This technical solution found that when the phase state of the self-supporting liquid crystal is smectic or nematic, it exhibits excellent electrically regulated ion transport performance. Furthermore, when the phase state of the self-supporting liquid crystal is smectic, the ion rectification effect is the best. Preferably, the phase state of the self-supporting liquid crystal is smectic.

[0008] In a preferred example, the two-dimensional oriented nanochannel of the self-supporting liquid crystal contains carboxyl groups connected by hydrogen bonds. This ensures that the two-dimensional oriented nanochannel is positively charged under acidic conditions and negatively charged under alkaline conditions, thus giving the material good ion rectification effect.

[0009] Furthermore, the size of the two-dimensional oriented nanochannels is between 1 and 10 nm. Nanochannels that are too large or too small are not only difficult to fabricate, but also detrimental to ion transport.

[0010] Preferably, the size of the two-dimensional oriented nanochannel is 1-3 nm. For example, the size of the two-dimensional oriented nanochannel includes, but is not limited to, 2-3 nm.

[0011] Furthermore, the thickness of the self-supporting liquid crystal is 5-50 μm. During fabrication, the thickness of the self-supporting smectic liquid crystal material can be controlled by changing the thickness of the spacers in the liquid crystal cell. For example, the thickness of the self-supporting liquid crystal is 10 μm.

[0012] Furthermore, the self-supporting liquid crystal is applied in the form of a polymer film for electrically regulated ion transport.

[0013] Furthermore, the material of the self-supporting liquid crystal is an aromatic liquid crystal compound and / or an aliphatic liquid crystal compound.

[0014] Furthermore, the fabrication of the self-supporting liquid crystal includes the following steps:

[0015] 1) Assemble glass sheets with polyvinyl alcohol alignment layers into a liquid crystal cell;

[0016] 2) The mixture of liquid crystal monomer, crosslinking agent and photoinitiator is poured into the liquid crystal cell at 90-110°C, preferably 105°C, and then the system is cooled down;

[0017] 3) Photopolymerization;

[0018] 4) Heat the system to 130-150℃ and hold for 5-20 minutes to finally obtain the self-supporting liquid crystal.

[0019] It should be noted that in this technical solution, the self-supporting liquid crystal can obtain different phase states, such as the nematic phase, by changing the polymerization temperature. Furthermore, when the temperature of the system after cooling in step 2) is 94-96℃, a smectic liquid crystal is obtained; when the temperature of the system after cooling in step 2) is 104-106℃, a nematic liquid crystal is obtained.

[0020] The self-supporting liquid crystal prepared by this method also has good mechanical properties.

[0021] Furthermore, the liquid crystal cell substrate is selected from ordinary glass, quartz wafers, or silicon wafers. A polyvinyl alcohol alignment layer is then coated onto the substrate.

[0022] Furthermore, the conditions for photopolymerization are: using 1-5 mW / cm 2 Polymerize under 365nm light for 5-20 minutes.

[0023] Furthermore, the photoinitiator is photoinitiator 184.

[0024] Furthermore, the liquid crystal monomer is

[0025] Further, the crosslinking agent is

[0026] Furthermore, the application includes the following steps:

[0027] At least a portion of the first surface of the self-supporting liquid crystal is placed in an acidic electrolyte, such that the corresponding nanochannel portion is positively charged.

[0028] The corresponding positions of the self-supporting liquid crystal on the second surface relative to the first surface are placed in an alkaline electrolyte, so that the corresponding nanochannel portions are negatively charged.

[0029] This method enables ion rectification.

[0030] It can be understood that the first and second surfaces of the self-supporting liquid crystal are two opposing surfaces, and their directions are perpendicular to the layers of the self-supporting liquid crystal structure.

[0031] Furthermore, the pH of the acidic electrolyte is 2-6, preferably 2-3, and more preferably 2.

[0032] Furthermore, the pH of the alkaline electrolyte is 8-12, preferably 10-11, and more preferably 11.

[0033] Furthermore, the electrolyte in the acidic and alkaline electrolytes is KCl with a concentration of 10. -3 ~10 -4 M can impart good ion rectification effect to smectic liquid crystal films. More preferably, it is 10. -4 M, in this case the aforementioned effect is even better.

[0034] Furthermore, the application includes the following steps:

[0035] At least a portion of the first surface of the self-supporting liquid crystal is placed in an acidic electrolyte, such that the corresponding nanochannel portion is positively charged.

[0036] The corresponding positions of the second surface of the self-supporting liquid crystal relative to the first surface are placed in an alkaline electrolyte, so that the corresponding nanochannel portions are negatively charged.

[0037] Maintain a constant voltage across both sides of the electrolytic cell;

[0038] A voltage is applied to the self-supporting liquid crystal, and the magnitude of the transfilm current is controlled by changing the magnitude of the voltage.

[0039] This method yielded excellent electro-controlled ion transport performance and achieved reversible variation of the transmembrane current magnitude.

[0040] It can be understood that the first and second surfaces of the self-supporting liquid crystal are two opposing surfaces, and their directions are perpendicular to the layers of the self-supporting liquid crystal structure.

[0041] It is also understood that the above steps can be achieved by placing the self-supporting liquid crystal in an electrolytic cell, while ensuring that at least part of the first surface of the self-supporting liquid crystal is in the acidic electrolyte and the corresponding part of the second surface is in the alkaline electrolyte.

[0042] Furthermore, the pH of the acidic electrolyte is 2-6, preferably 2-3, and more preferably 2.

[0043] Furthermore, the pH of the alkaline electrolyte is 8-12, preferably 10-11, and more preferably 11.

[0044] Furthermore, the electrolyte in the acidic and alkaline electrolytes is KCl, preferably with a concentration of 10%. -6 M.

[0045] Furthermore, the constant voltage is 1V.

[0046] Furthermore, the voltage applied to the self-supporting liquid crystal is in the range of 0V-0.5V. This enables reversible changes in the transfilm current, for example, from 0μA to 5.8μA.

[0047] The beneficial effects of this invention are as follows:

[0048] This invention is the first to realize the use of liquid crystals with specific structures in electrically controlled ion transport. The magnitude of the transmembrane current can be effectively controlled by the voltage applied to it. Moreover, the self-supporting liquid crystal preparation method is simple, low-cost, and suitable for large-scale preparation. Attached Figure Description

[0049] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0050] Figure 1 Macroscopic images, scanning electron microscope images, atomic force microscopy images, transmission electron microscope images, and nanoindentation data of the self-supporting smectic liquid crystal material prepared in Example 1 are shown.

[0051] Figure 2 Differential scanning calorimetry (DSC) data and X-ray diffraction (XRD) data of the self-supporting smectic liquid crystal material prepared in Example 1 are shown.

[0052] Figure 3The Zeta potential data, current-voltage curves, and rectification ratios at different concentrations of the self-supporting smectic liquid crystal material prepared in Example 1 are shown.

[0053] Figure 4 This demonstrates the reversible change of transfilm current in the self-supporting smectic liquid crystal material prepared in Example 1 under voltage regulation. Detailed Implementation

[0054] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments and accompanying drawings, further explains the invention. Similar components in the drawings are indicated by the same reference numerals. Those skilled in the art should understand that the specific description below is illustrative rather than restrictive and should not be construed as limiting the scope of protection of the present invention.

[0055] It should be noted that in the following embodiments, the liquid crystal monomer 6OBA refers to:

[0056]

[0057] The liquid crystal crosslinking agent C6H refers to:

[0058]

[0059] Example 1

[0060] Preparation of self-supporting smectic liquid crystal materials:

[0061] 1) Assemble glass sheets with polyvinyl alcohol alignment layers into a liquid crystal cell (10 μm spacing);

[0062] 2) Combine C6H / 6OBA (weight ratio 1:9, structural formulas of both are as follows) Figure 1 The mixture of (as shown in A) and 2 mol% photoinitiator 184 was poured into a liquid crystal cell at 105 °C, and then the system was cooled to 95 °C.

[0063] 3) Use 5mW / cm 2 Polymerize under 365nm light for 5 minutes;

[0064] 4) Heat the system to 135°C and hold for 5 minutes to obtain a self-supporting smectic liquid crystal material.

[0065] Mechanical strength and morphology characterization results of self-supporting smectic liquid crystal materials

[0066] The obtained self-supporting smectic liquid crystal material was subjected to mechanical property characterization tests, such as... Figure 1Figures B and C show that B1 represents the smectic liquid crystal material's ability to withstand a 50g weight while maintaining good flexibility, B2 is a macroscopic view of a large-area smectic liquid crystal material, and C represents the modulus and hardness of different phases (smectic, nematic, and isotropic) of liquid crystal materials obtained through nanoindentation experiments. A 5cm × 5cm large-area self-supporting smectic liquid crystal polymer film can be prepared, capable of withstanding a 50g weight. Nanoindentation data indicates that the modulus of the self-supporting smectic liquid crystal material is 0.6 GPa, and its hardness is 0.08 GPa. Scanning electron microscope images (SEM images) are also provided. Figure 1 (D) indicates that the prepared smectic liquid crystal film is dense and continuous, with no cracks in the top layer and cross-section, and a thickness of approximately 10 μm. The atomic force image of this smectic liquid crystal film ( Figure 1 (E) indicates that the film surface is smooth with a roughness of approximately 6 nm. (Transmission electron microscopy image) Figure 1 (F) indicates that the membrane interior is rich in ordered / oriented nanochannels with a pore size of approximately 3 nm. X-ray diffraction also shows that the pore size of the nanochannels inside the membrane is 2.9 nm, consistent with the results observed by transmission electron microscopy. Figure 2 (B) Differential scanning calorimetry (DSC) Figure 2 (A) indicates that the glass transition temperature of the film is 72℃ and the phase transition temperature is 178℃.

[0067] Example 2

[0068] Characterization of rectification performance of self-supporting smectic liquid crystal materials

[0069] The rectification performance of the self-supporting smectic liquid crystal material prepared in Example 1 was studied.

[0070] The self-supporting smectic liquid crystal material was placed in different pH environments (e.g., pH ranges from 3 to 11, such as pH 3, 4, 5, 6, 6.5, 8, 9, 10.5, etc.). It was found that the nanochannels in the self-supporting smectic liquid crystal material can carry positive or negative charges under acidic or alkaline conditions, respectively. For example, at pH = 3, the Zeta potential within the nanochannels is 16 mV. At pH = 10.5, the Zeta potential within the nanochannels is -58 mV. Figure 3 (A)).

[0071] The ion rectification performance of this self-supporting smectic liquid crystal material was tested, including the following steps:

[0072] At least a portion of the first surface of the self-supporting liquid crystal is placed in a solution of pH 2 at a concentration of 10. -4 In the M KCl electrolyte, the corresponding nanochannel portion becomes positively charged;

[0073] The corresponding position of the self-supporting liquid crystal relative to the second surface of the first surface is placed at pH 11. -4 In MKCl electrolyte, the corresponding nanochannel portion becomes negatively charged.

[0074] Measure the current-voltage curve ( Figure 3 (B), where the applied voltages range from -2V to 2V, with intervals of 0.25V. In the negative voltage range, there is a significant transfilm current. For example, the current is -123μA at -2V. In the positive voltage range, the transfilm current is almost zero. For example, the current is 2.5μA at 2V. The rectification ratio of the liquid crystal material in this state is approximately 50 (…). Figure 3 (D)).

[0075] Further investigation was conducted on the liquid crystal material at different concentrations (using the same method as above for testing ion rectification performance, the difference being that the concentration of the electrolyte KCl was adjusted to 10). -6 M, 10 -5 M, 10 -4 M, 10 -3 The rectification effect in electrolytes of M, 0.01M, and 0.1M. The rectification effect of liquid crystal materials exhibits a unimodal distribution with solution concentration. Figure 3 (C)). As can be seen from the figure, the double layer thickness and the size of the nanochannels are more matched in the appropriate electrolyte concentration, resulting in better rectification effect.

[0076] Example 3

[0077] Electromodulation of ion transport in self-supporting smectic liquid crystal materials:

[0078] The electrically modulated ion transport properties of the self-supported smectic liquid crystal material prepared in Example 1 were investigated. The experimental setup was as follows: Figure 4 As shown in (A). The method specifically includes the following steps:

[0079] At least a portion of the first surface of the smectic liquid crystal material was placed in a solution of pH 2 at a concentration of 10. -6 In the M KCl electrolyte, the corresponding nanochannel portion becomes positively charged;

[0080] The corresponding positions of the second surface of the first surface of the smectic liquid crystal material are placed at pH 11. - 6 In MKCl electrolyte, the corresponding nanochannel portion becomes negatively charged;

[0081] By maintaining a 1V voltage across the electrolytic cell and applying voltages of 0 to 0.5V (0V, 0.1V, 0.2V, 0.3V, 0.4V, 0.5V) to the smectite liquid crystal material, a reversible transition of the transmembrane current from 0μA to 5.8μA can be achieved. Figure 4(B) Furthermore, applying a sinusoidal voltage to smectic liquid crystal materials can achieve multiple reversible transitions of the transfilm current from 0 μA to 5.5 μA. Figure 4 (C)).

[0082] Example 4

[0083] Preparation of self-supporting smectic liquid crystal materials:

[0084] 1) Assemble glass sheets with polyvinyl alcohol alignment layers into a liquid crystal cell (10 μm spacing);

[0085] 2) The mixture of C6H / 6OBA (weight ratio 3:7) and 2 mol% photoinitiator 184 was poured into a liquid crystal cell at 105°C, and then the system was cooled to 95°C.

[0086] 3) Use 5mW / cm 2 Polymerize under 365nm light for 5 minutes;

[0087] 4) Heat the system to 135°C and hold for 5 minutes to obtain a self-supporting smectic liquid crystal material.

[0088] Example 5

[0089] Preparation of self-supporting smectic liquid crystal materials:

[0090] 1) Assemble glass sheets with polyvinyl alcohol alignment layers into a liquid crystal cell (10 μm spacing);

[0091] 2) The mixture of C6H / 6OBA (weight ratio 5:5) and 2 mol% photoinitiator 184 was poured into a liquid crystal cell at 105°C, and then the system was cooled to 95°C.

[0092] 3) Use 5mW / cm 2 Polymerize under 365nm light for 5 minutes;

[0093] 4) Heat the system to 135°C and hold for 5 minutes to obtain a self-supporting smectic liquid crystal material.

[0094] Example 6

[0095] Preparation of self-supporting smectic liquid crystal materials

[0096] 1) Assemble glass sheets with polyvinyl alcohol alignment layers into a liquid crystal cell (5μm spacing);

[0097] 2) The mixture of C6H / 6OBA (weight ratio 1:9) and 2 mol% photoinitiator 184 was poured into a liquid crystal cell at 105°C, and then the system was cooled to 95°C.

[0098] 3) Use 5mW / cm 2Polymerize under 365nm light for 5 minutes;

[0099] 4) Heat the system to 135°C and hold for 5 minutes to obtain a self-supporting smectic liquid crystal material.

[0100] Example 7

[0101] Preparation of self-supporting smectic liquid crystal materials

[0102] 1) Assemble glass sheets with polyvinyl alcohol alignment layers into a liquid crystal cell (spaced 20 μm apart);

[0103] 2) The mixture of C6H / 6OBA (weight ratio 1:9) and 2 mol% photoinitiator 184 was poured into a liquid crystal cell at 105°C, and then the system was cooled to 95°C.

[0104] 3) Use 5mW / cm 2 Polymerize under 365nm light for 5 minutes;

[0105] 4) Heat the system to 135°C and hold for 5 minutes to obtain a self-supporting smectic liquid crystal material.

[0106] Example 8

[0107] Preparation of self-supporting smectic liquid crystal materials

[0108] 1) Assemble glass sheets with polyvinyl alcohol alignment layers into a liquid crystal cell (spaced 30 μm apart);

[0109] 2) The mixture of C6H / 6OBA (weight ratio 1:9) and 2 mol% photoinitiator 184 was poured into a liquid crystal cell at 105°C, and then the system was cooled to 95°C.

[0110] 3) Use 5mW / cm 2 Polymerize under 365nm light for 5 minutes;

[0111] 4) Heat the system to 135°C and hold for 5 minutes to obtain a self-supporting smectic liquid crystal material.

[0112] Example 9

[0113] Preparation of self-supported nematic liquid crystal materials

[0114] 1) Assemble glass sheets with polyvinyl alcohol alignment layers into a liquid crystal cell (10 μm spacing);

[0115] 2) The mixture of C6H / 6OBA (weight ratio 1:9) and 2 mol% photoinitiator 184 was poured into a liquid crystal cell at 105 °C, and then the system was cooled to 105 °C.

[0116] 3) Use 5mW / cm2 Polymerize under 365nm light for 5 minutes;

[0117] 4) Heat the system to 135°C and hold for 5 minutes to obtain a self-supporting smectic liquid crystal material.

[0118] Example 10

[0119] Preparation of self-supporting smectic liquid crystal materials

[0120] 1) Assemble glass sheets with polyvinyl alcohol alignment layers into a liquid crystal cell (10 μm spacing);

[0121] 2) The mixture of C6H / 6OBA (weight ratio 1:9) and 2 mol% photoinitiator 184 was poured into a liquid crystal cell at 105°C, and then the system was cooled to 95°C.

[0122] 3) Use 1mW / cm 2 Polymerization under 365nm light for 20 minutes;

[0123] 4) Heat the system to 135°C and hold for 5 minutes to obtain a self-supporting smectic liquid crystal material.

[0124] The electro-modulated ion transport performance of the self-supporting smectic liquid crystal materials of Examples 4-10 was tested according to the method of Example 3, and the results also showed good electro-modulated ion transport performance.

[0125] Example 11

[0126] Preparation of self-supported nematic liquid crystal materials:

[0127] 1) Assemble glass sheets with polyvinyl alcohol alignment layers into a liquid crystal cell (10 μm spacing);

[0128] 2) The mixture of C6H / 6OBA (weight ratio 1:9) and 2 mol% photoinitiator 184 was poured into a liquid crystal cell at 105°C, and then the system was kept at 105°C.

[0129] 3) Use 5mW / cm 2 Polymerize under 365nm light for 5 minutes;

[0130] 4) Heat the system to 135°C and hold for 5 minutes to obtain a self-supporting nematic liquid crystal material.

[0131] Compared with the smectic liquid crystal material prepared in Example 1, the nematic liquid crystal material has a rectification ratio of only 20 under the same experimental conditions. Figure 3 (D)).

[0132] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. An application of a self-supporting liquid crystal in electrically controlled ion transport, characterized in that, The phase state of the self-supporting liquid crystal is a smectic phase or a nematic phase; The self-supporting liquid crystal contains two-dimensional oriented nanochannels between its layers, and these two-dimensional oriented nanochannels are positively charged under acidic conditions and negatively charged under alkaline conditions.

2. The application according to claim 1, characterized in that, The two-dimensional oriented nanochannels contain hydrogen-bonded carboxyl groups.

3. The application according to claim 1, characterized in that, The dimensions of the two-dimensional oriented nanochannels are between 1 and 10 nm.

4. The application according to claim 1, characterized in that, The dimensions of the two-dimensional oriented nanochannels are 1-3 nm.

5. The application according to claim 1, characterized in that, The self-supporting liquid crystal is made of aromatic liquid crystal compounds and / or aliphatic liquid crystal compounds.

6. The application according to claim 1, characterized in that, The preparation of the self-supporting liquid crystal includes the following steps: 1) Assemble glass sheets with polyvinyl alcohol alignment layers into a liquid crystal cell; 2) The mixture of liquid crystal monomer, crosslinking agent and photoinitiator is poured into the liquid crystal cell at 90-110℃, and then the system is cooled down; 3) Photopolymerization; 4) Heat the system to 130-150℃ and hold for 5-20 minutes to finally obtain the self-supporting liquid crystal.

7. The application according to claim 6, characterized in that, The temperature after cooling is 94-96℃ or 104-106℃.

8. The application according to claim 6, characterized in that, The conditions for photopolymerization are: 1-5 mW / cm 2 Polymerize under 365nm light for 5-20 minutes.

9. The application according to any one of claims 1-3, characterized in that, Includes the following steps: At least a portion of the first surface of the self-supporting liquid crystal is placed in an acidic electrolyte, such that the corresponding nanochannel portion is positively charged. The corresponding positions of the self-supporting liquid crystal on the second surface relative to the first surface are placed in an alkaline electrolyte, so that the corresponding nanochannel portions are negatively charged.

10. The application according to claim 9, characterized in that, The pH of the acidic electrolyte is 2-6; and / or The pH of the alkaline electrolyte is 8-12; and / or The electrolyte in both the acidic and alkaline electrolytes is KCl, with a concentration of 10%. -3 ~10 -4 M.

11. The application according to claim 9, characterized in that, The pH of the acidic electrolyte is 2.

12. The application according to claim 9, characterized in that, The pH of the alkaline electrolyte is 11.

13. The application according to claim 9, characterized in that, The electrolyte in both the acidic and alkaline electrolytes is KCl, with a concentration of 10%. -4 M.

14. The application according to any one of claims 1-3, characterized in that, Includes the following steps: At least a portion of the first surface of the self-supporting liquid crystal is placed in an acidic electrolyte, such that the corresponding nanochannel portion is positively charged. The corresponding positions of the second surface of the self-supporting liquid crystal relative to the first surface are placed in an alkaline electrolyte, so that the corresponding nanochannel portions are negatively charged. Maintain a constant voltage across both sides of the electrolytic cell; A voltage is applied to the self-supporting liquid crystal, and the magnitude of the transfilm current is controlled by changing the magnitude of the voltage.

15. The application according to claim 14, characterized in that, The pH of the acidic electrolyte is 2-6; and / or The pH of the alkaline electrolyte is 8-12; and / or The electrolyte in both the acidic and alkaline electrolytes is KCl, with a concentration of 10%. -6 M.

16. The application according to claim 14, characterized in that, The pH of the acidic electrolyte is 2.

17. The application according to claim 14, characterized in that, The pH of the alkaline electrolyte is 11.

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