1. A method for preparing programmable spider silk-like fiber is characterized by comprising the following steps:

1) building a piezoelectric micro-flow platform: a piezoelectric disturbance device is added at the upstream of the microfluidic chip, and a vibration signal is transmitted to the internal phase fluid through a film;

2) forming a stable jet flow: selecting a photo-curable aqueous phase polymer solution as an internal phase and pure water as an external phase, wherein a two-aqueous phase fluid in the chip has low interfacial tension and is under the condition of low Reynolds number, so that a stable laminar flow can be formed in a channel;

3) introducing external disturbance: introducing disturbance into the internal phase in the step 2) by using an external piezoelectric stack, and editing the piezoelectric signal to adjust the flow velocity of the internal phase fluid as required to form a wave shape corresponding to the piezoelectric signal on the surface of the jet flow;

4) solidifying the wave jet flow to prepare the spider silk-like fiber with the spindle knot: irradiating the wave jet formed in the step 3) by using ultraviolet light to perform polymerization reaction, obtaining spindle section fibers with similar shapes at the downstream, and accurately adjusting the diameter of the spindle section fibers and the size of a spindle structure by adjusting the flow ratio of the inner phase and the outer phase and the frequency and the amplitude of a piezoelectric signal.

2. A method of producing a programmable spidroin-like fiber according to claim 1, characterized in that: in the step 1), the microfluidic chip is assembled by a glass capillary, a glass slide, a sample application needle and quick-drying glue, wherein the glass capillary is assembled by coaxially nesting an outer phase capillary and an inner phase capillary.

3. A method of producing a programmable spidroin-like fiber according to claim 2, characterized in that: the diameter of the external phase capillary tube is 500-1600 mu m, the diameter of the internal phase capillary tube is 40-400 mu m, and the diameters of the internal phase jet flow and the wave fiber can be adjusted by changing the flow velocity of the internal phase and the external phase or the diameters of the internal phase and the external phase capillary tubes.

4. A method of producing a programmable spidroin-like fiber according to claim 2, characterized in that: in the step 2), piezoelectric ceramics is adopted to provide external disturbance, the piezoelectric ceramics extrudes the internal phase fluid as required under an external signal to modulate the flow velocity of the internal phase fluid, and the external disturbance is very sensitive due to extremely low interfacial tension in the double-aqueous-phase system, so that the downstream jet flow forms a corresponding wave shape.

5. A method of producing a programmable spidroin-like fiber according to claim 3, characterized in that: in the step 1), a photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-acetone HMPP polyethylene glycol diacrylate PEGDA is added into the inner phase photo-curable polymer, and deionized water is used as the outer phase.

6. A method of producing a programmable spidroin-like fiber according to claim 1, characterized in that: in step 2), the external signal is a periodic wave or a self-defined signal wave without a periodic structure.

7. A method of making a programmable spidroin-like fiber according to claim 6, characterized in that: in the step 2), the external signal is a sine wave, a square wave or a sawtooth wave.

8. A method of producing a programmable spidroin-like fiber according to claim 1, characterized in that: in the step 3), the jet flow with the wave morphology is solidified by using ultraviolet light, so that the wave fiber can be continuously prepared.

9. A programmable spider silk-like fiber, characterized by being prepared by the preparation method of any one of claims 1 to 8.

Background

Natural evolution confers a unique structure on organisms to control directed hydrodynamics for survival. Spider silks are one of the most important structures in nature for controlling droplet behavior, and represent an emerging material with periodic spindle knots. Due to their geometry and wettable gradient properties, they can achieve condensation and collection of water. However, the manufacture of such micron-sized spindle-bonded fibrous materials remains a significant challenge. The common methods are as follows: a lifting coating Rayleigh instability technology, a coaxial electrostatic spinning technology and the like. However, all of the above methods have inherent defects of poor controllability, and therefore, development of new preparation techniques is urgently needed. The microfluidic technology can integrate different fluids into a system in a specific mode at a microscopic scale, and the flow mode of the system can be accurately controlled. With microfluidic technology, microfibers of various controllable sizes and morphologies can be continuously produced using microfluidic technology. And by combining the micro-fluidic spinning technology and the emulsification technology, the microfiber with uniform spindle knots can be easily prepared on a large scale. However, the same batch of spindle pitch microfibers currently produced using microfluidics generally have the same pitch and pitch height, which greatly limits their further applications.

Disclosure of Invention

The invention aims to provide a programmable spider silk-like fiber and a preparation method thereof aiming at the defects of the prior art. The appearance of the obtained fiber is controlled by a piezoelectric signal, and the piezoelectric signal can be edited by self-definition, so that the spider silk-like fibers with various appearances can be generated as required.

In order to achieve the purpose, the technical scheme provided by the invention is as follows:

a method for preparing programmable spider silk-like fiber comprises the following steps:

1) building a piezoelectric micro-flow platform: a piezoelectric disturbance device is added at the upstream of the microfluidic chip, and a vibration signal is transmitted to the internal phase fluid through a film;

2) forming a stable jet flow: selecting a photo-curable aqueous phase polymer solution as an internal phase and pure water as an external phase, wherein a two-aqueous phase fluid in the chip has low interfacial tension and is under the condition of low Reynolds number, so that a stable laminar flow can be formed in a channel;

3) introducing external disturbance: introducing disturbance into the internal phase in the step 2) by using an external piezoelectric stack, and editing the piezoelectric signal to adjust the flow velocity of the internal phase fluid as required to form a wave shape corresponding to the piezoelectric signal on the surface of the jet flow;

4) solidifying the wave jet flow to prepare the spider silk-like fiber with the spindle knot: irradiating the wave jet formed in the step 3) by using ultraviolet light to perform polymerization reaction, obtaining spindle section fibers with similar shapes at the downstream, and accurately adjusting the diameter of the spindle section fibers and the size of a spindle structure by adjusting the flow ratio of the inner phase and the outer phase and the frequency and the amplitude of a piezoelectric signal.

Further, in the step 1), the microfluidic chip is assembled by a glass capillary, a glass slide, a sample application needle and quick-drying glue, wherein the glass capillary is assembled by coaxially nesting an external phase capillary and an internal phase capillary.

The diameter of the external phase capillary tube is 500-1600 mu m, the diameter of the internal phase capillary tube is 40-400 mu m, and the diameters of the internal phase jet flow and the wave fiber can be adjusted by changing the flow velocity of the internal phase and the external phase or the diameters of the internal phase and the external phase capillary tubes.

In the step 2), piezoelectric ceramics is adopted to provide external disturbance, the piezoelectric ceramics extrudes internal phase fluid according to needs under an external signal, the flow rate of the internal phase fluid is modulated, and the external disturbance is very sensitive due to extremely low interfacial tension in a double-water-phase system, so that in the step 1) of forming a corresponding wave shape by downstream jet flow, polyethylene glycol diacrylate PEGDA of 2-hydroxy-2-methyl-1-phenyl-1-acetone HMPP is added into the internal phase photo-curable polymer, and deionized water is used for an external phase.

In step 2), the external signal is a periodic wave or a self-defined signal wave without a periodic structure.

Preferably, in step 2), the external signal is a sine wave, a square wave or a sawtooth wave.

In the step 3), the jet flow with the wave morphology is solidified by using ultraviolet light, so that the wave fiber can be continuously prepared.

The invention also protects the programmable spider silk-like fiber prepared by the preparation method.

The invention provides a method for preparing programmable spider silk-like fibers, which is based on the characteristic that jet flow quickly responds to external disturbance, can flexibly control a plurality of characteristic sizes of the spider silk-like fibers as required by self-defining editing of piezoelectric signals, and has important significance for quick, continuous and controllable preparation of the programmable fibers. Compared with the prior art, the invention has the beneficial effects that:

1) compared with the traditional spider silk-like fiber preparation method, the preparation method provided by the invention has the advantages that the micro-fluidic chip is utilized to form the wavy jet flow, so that the fiber with the spider silk-like structure is formed through solidification, the preparation process is simple and controllable, and the requirement on operation conditions is low;

2) the preparation method relies on a piezoelectric micro-fluidic technology, adopts a micro-fluidic chip to prepare the spider silk-like fiber, does not need additional fluid to assist in forming a spindle structure, and has simple and controllable process; the diameter of the fiber can be adjusted by the flow rate ratio of the internal phase and the external phase and the pipe diameter of the external phase capillary, so that the operation is convenient; in addition, the distance between the spindle sections and the section height can be accurately controlled through the frequency and the amplitude of the piezoelectric signal.

Drawings

FIG. 1 is a flow chart of the preparation process for preparing the wave fiber according to the invention.

FIG. 2 is a schematic diagram of FIG. 1 illustrating the application of external perturbations.

FIG. 3 is a schematic diagram of different piezoelectric signals and corresponding spindle-segmented cobweb fibers in FIG. 1.

Detailed Description

The above-mentioned contents of the present invention are further described in detail by way of examples below, but it should not be understood that the scope of the above-mentioned subject matter of the present invention is limited to the following examples, and any technique realized based on the above-mentioned contents of the present invention falls within the scope of the present invention.

The experimental procedures used in the examples below are conventional procedures unless otherwise specified, and the reagents, methods and equipment used therein are conventional in the art unless otherwise specified.

Example 1

A method for preparing programmable spider silk-like fiber comprises the following steps:

(1) building a piezoelectric micro-flow platform: a piezoelectric perturbation device is added at the upstream of the microfluidic chip, and a vibration signal is transmitted to the internal phase fluid through a film.

(2) Forming a stable jet flow: selecting a photo-curable aqueous phase polymer solution as an internal phase and pure water as an external phase, wherein a two-phase fluid in a chip has very low interfacial tension and is under the condition of low Reynolds number, so that a stable laminar flow can be formed in a channel;

(3) introducing external disturbance: and (3) introducing disturbance into the internal phase in the step (2) by using an external piezoelectric stack, and editing the piezoelectric signal to enable the piezoelectric signal to adjust the flow velocity of the internal phase fluid as required, so that the wave morphology corresponding to the piezoelectric signal can be formed on the surface of the jet flow.

(4) Solidifying wave jet flow to prepare the spider silk-like fiber: and (3) irradiating the wave jet formed in the step (3) by using ultraviolet light to perform polymerization reaction, obtaining the spider silk-like fiber with similar appearance at the downstream, and adjusting the flow ratio of the internal phase and the external phase and the frequency and amplitude of the piezoelectric signal to accurately adjust the diameter of the spider silk-like fiber and the size of the spindle structure.

In the step (1), the microfluidic chip is assembled by a glass capillary tube, a glass slide, a sample application needle and quick-drying glue, wherein the inner phase capillary tube and the outer phase capillary tube form a coaxial nested structure. The piezoelectric perturbation device mainly comprises a piezoelectric stack and a film, wherein the piezoelectric stack can extrude an internal phase fluid as required under a piezoelectric signal to modulate the flow rate of the internal phase fluid, as shown in figure 1. Further, the outer phase capillary tube diameter is 500-1600 mu m, the inner phase capillary tube diameter is 40-400 mu m, and the diameters of the inner phase jet flow and the spider silk-like fibers are adjustable by changing the inner phase flow velocity and the outer phase flow velocity or the inner phase and outer phase capillary tube diameters.

In the step (2), the inner phase is a polyethylene glycol diacrylate (PEGDA) aqueous solution added with a photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-acetone (HMPP), and the outer phase uses deionized water. Wherein the volume fraction of the PEGDA is 5-30%, and the volume fraction of the photoinitiator HMPP is 0.5-4%.

In the step (3), piezoelectric ceramics is adopted to provide external disturbance, and the piezoelectric ceramics can extrude the internal phase fluid as required under an external signal, as shown in fig. 2.

In the step (4), the jet flow with the wave morphology is solidified by using ultraviolet light, and the programmable spider silk-like fiber can be continuously prepared.

Example 2

A programmable spider silk-like fiber preparation process is shown in figure 1 and comprises the following steps:

(1) preparing an internal phase solution and an external phase solution:

1.1) internal phase solution: consists of an aqueous solution of HMPP/PEGDA; a PEGDA aqueous solution with the volume fraction of PEGDA of 5-30%;

1.2) external phase solution: deionized water.

(2) Assembling the microfluidic chip: the microelectrode drawing instrument is used for drawing the glass capillary, the diameter of the inner phase glass capillary is 40-400 mu m, the diameter of the outer phase glass capillary is 500-1600 mu m, the microfluidic chip is assembled by the inner and outer phase glass capillary, a glass slide, a sample application needle head and quick-drying glue, and the inner phase glass capillary and the outer phase glass capillary keep a coaxial structure.

(3) Forming a stable jet flow:

and introducing the internal phase and the external phase into the microfluidic chip by using an injection pump, setting the flow velocity of the internal phase and the flow velocity of the external phase, and starting the injection pump to work. In the microfluidic channel, because the two-phase fluid in the chip has very low interfacial tension and the fluid is under the condition of low Reynolds number, stable and slender jet flow can be formed in the channel.

(4) Introducing external disturbance:

a piezoelectric stack is introduced between the inner phase fluid tubes as an external perturbation source. The self-defined waveform is edited by an upper computer (computer), a transmitted signal generator generates a corresponding signal, the signal is amplified by a power amplifier and finally connected to the piezoelectric ceramic to generate vibration of the corresponding waveform, the piezoelectric stack couples vibration information into the inner phase fluid through a film, the inner phase fluid is modulated by external disturbance to cause fluctuation, and the double water phase interface has extremely low interface tension, so that a wave morphology corresponding to the disturbance can be formed on the surface of the jet flow.

FIG. 3 is a schematic diagram of spider silk-like fibers corresponding to different programming signals, wherein increasing the frequency (pulse width) of the external disturbance decreases the pitch of the wave jet, and increasing the amplitude of the disturbance increases the wave width of the wave jet.

(5) Preparing the spider silk-like fiber:

and irradiating jet flow with wave morphology formed in the piezoelectric micro-fluidic chip by using ultraviolet light, and performing polymerization reaction to obtain programmable spider silk-like fibers at downstream.

The control of the programmable spider silk-like fiber can be mainly realized by adjusting the frequency (pulse width) and amplitude of external disturbance:

the flow parameters in the preparation process are controlled to be unchanged, the fiber morphology can be programmed and designed by customizing the disturbance waveform, the spider silk-like fibers with different morphologies are obtained, and a typical result is shown in fig. 3.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention in any way, and any person skilled in the art can make any simple modification, equivalent replacement, and improvement on the above embodiment without departing from the technical spirit of the present invention, and still fall within the protection scope of the technical solution of the present invention.