CN114177959A - Preparation method of nano-fluidic chip based on carbon nano-tube - Google Patents
Preparation method of nano-fluidic chip based on carbon nano-tube Download PDFInfo
- Publication number
- CN114177959A CN114177959A CN202111537020.9A CN202111537020A CN114177959A CN 114177959 A CN114177959 A CN 114177959A CN 202111537020 A CN202111537020 A CN 202111537020A CN 114177959 A CN114177959 A CN 114177959A
- Authority
- CN
- China
- Prior art keywords
- carbon nano
- nano tube
- nanotubes
- channel
- nano
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
- B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
- B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
- B01L3/5027—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip
- B01L3/502707—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by the manufacture of the container or its components
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Dispersion Chemistry (AREA)
- Analytical Chemistry (AREA)
- General Health & Medical Sciences (AREA)
- Hematology (AREA)
- Clinical Laboratory Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Micromachines (AREA)
Abstract
The application provides a high-precision machining method for a nano channel based on a carbon nano tube, and corresponding application and products. The processing method comprises the steps of etching a mark on a substrate, growing a carbon nano tube horizontal array, protecting the carbon nano tube required by photoresist, etching the carbon nano tube by oxygen plasma, constructing a micro-channel by photoetching, breaking the carbon nano tube, bonding PDMS (polydimethylsiloxane) and installing a liquid inlet pipe and a liquid outlet pipe. The method has the advantages of high processing precision, simplicity in operation, high compatibility with the traditional technology, large designable space, high length-diameter ratio of the prepared nano channel, good uniformity and stability along the axis direction of the nano tube, capability of reducing the minimum size to 0.4nm, accurate and controllable size, good sealing property and difficulty in liquid leakage when the fluid medium moves along the nano channel.
Description
Technical Field
The application belongs to the field of new biomedical materials, and particularly relates to a high-precision machining method of a nano channel based on a carbon nano tube and application of the nano channel in the field of biomedicine.
Background
The nanochannel has a wide range of applications in a number of fields, such as biosensors for virus and biomacromolecule detection, nanomedicine development, nanofluidic chips, high thermal flux density chip heat dissipation, and the like. Whether it be current changes during detection or accurate delivery and detection of drugs, nanochannels are required to have good uniformity (generally referred to as high uniformity along the length of the nanochannels), hermeticity, and economy to achieve high signal-to-noise ratios and practical value.
The current commonly used methods for preparing nanochannels include traditional photolithography, high energy beam processing, nanoimprint lithography, and the like:
the traditional photoetching method can realize batch processing through etching of a mask plate, and the method is widely applied to the preparation of microfluidic chips, however, the transverse dimension of a channel processed by the method is limited by the wavelength of UV (ultraviolet rays) light, the width of the channel is generally limited to micron level, the method has strict requirements on etching rate, and the problem of uneven height of a nano channel in the length direction is easily caused. The micron-scale lithography limits the fabrication of nanochannels due to its low resolution, and lithography equipment with nanometer-scale precision is too expensive to be suitable for the fabrication of nanofluidic chips, and thus this approach still has limitations.
High-energy beam processing methods using electron beams, proton beams, focused ion beams, femtosecond laser beams, and the like, make materials physically and chemically changed by direct irradiation of the high-energy beams on the materials, thereby manufacturing nanochannels, and such methods require expensive processing equipment, are difficult to realize parallel processing of a plurality of nanochannels, and have high preparation cost and low efficiency.
The nano-imprint lithography is a preparation method combining nano-imprint lithography and lithography, and has the following principle: the method is a technology for realizing the copying of a micro-nano structure pattern by using a mold containing a micro-nano structure to imprint on a material to be processed with the assistance of polymers such as photoresist and the like. The method generally comprises three steps: the method comprises the steps of processing an imprinting template, transferring patterns and processing a substrate, namely processing a mold by means of etching and the like, covering the surface of a material to be processed with polymers such as photoresist and the like as a buffer layer, imprinting the mold on the surface of the material to be processed to generate mechanical deformation, irradiating the material by ultraviolet light and the like to solidify the material, and removing the buffer layer to obtain a micro-nano structure material consistent with the structure of the mold. The prior art has the defects of accurately controlling the size of the channel, effectively controlling the roughness of the wall surface and the uniformity of the channel.
In conclusion, the development of a nano-channel preparation method which can accurately regulate and control the size of a nano-channel and has strong practicability is significant for breakthrough of key core technologies of virus and biomacromolecule detection technologies, nano-medicine, nano-fluidic devices and heat dissipation of high-heat-flux chips.
A carbon nano tube, also called a buckytubes tube, is a one-dimensional quantum material with a special structure (the radial dimension is nano-scale, the axial dimension is micron-scale, and two ends of the tube are basically sealed), belonging to the frontier new material and the nano material in the new material field. The carbon nanotube mainly comprises several layers to tens of layers of coaxial circular tubes formed by hexagonally arranged carbon atoms, and a fixed distance of about 0.34nm is kept between the layers. The carbon nanotube can be regarded as a graphene sheet layer which is curled, and thus the number of layers of the graphene sheet can be divided into: single-walled Carbon nanotubes (or Single-walled Carbon nanotubes, SWCNTs) and Multi-walled Carbon nanotubes (or Multi-walled Carbon nanotubes, MWCNTs) have typical diameters of 0.6 to 2nm, and the innermost layer of a Multi-walled tube can reach 0.4nm, and the thickest can reach several hundreds of nanometers, but the typical tube diameter is 2 to 100 nm. The carbon nano tube is used as a one-dimensional nano material, has light weight, perfect connection of a hexagonal structure, natural nanoscale diameter, high length-diameter ratio and natural atomic-level smooth inner wall, has structural and property uniformity along the axial direction of the nano tube, and has excellent mechanical, electrical and thermal properties and chemical stability.
Disclosure of Invention
The invention applies the carbon nano tube to the preparation of the nano flow control chip and provides a nano channel high-precision processing method based on the carbon nano tube.
In one aspect, the present application provides a nanotube-based nanochannel processing method comprising:
firstly, etching a mark on a substrate;
growing a carbon nano tube horizontal array on the substrate with the etched mark;
protecting the required carbon nano tube by photoresist;
etching other redundant carbon nano tubes by using oxygen plasma;
constructing a micro-channel on the required carbon nano-tube by a photoetching method;
step six, breaking two ends of the carbon nano tube;
bonding a layer of pre-perforated PDMS on the upper surface of the micro flow channel;
step eight, inserting a liquid inlet pipe and a liquid outlet pipe at the reserved punching position.
Further, the substrate is Si/SiO2And (3) slicing.
Further, the nanotubes are carbon nanotubes or boron nitride nanotubes.
Further, the nanotubes are carbon nanotubes.
Further, step three uses positive photoresist and step five uses negative photoresist.
Further, AZ 15004.4 cp photoresist positive electrode was used in step three, and SU-82050 photoresist negative electrode was used in step five.
Further, the third step comprises the steps of glue homogenizing, pre-baking, exposure, developing and cleaning; and the fifth step comprises the steps of glue homogenizing, pre-baking, exposure, post-baking, developing and cleaning.
Furthermore, in the sixth step, the FIB precise etching technology is used to break the two ends of the carbon nanotube.
Further, step eight includes the step of inserting an electrode at the liquid outlet.
In another aspect, the present application provides nanotube-based nanochannels prepared using the above-described methods.
On the other hand, the application provides the application of the method in preparing virus or biological macromolecule detection devices, nano-fluidic devices, high heat flow density chip heat dissipation devices or drug carriers.
In another aspect, the present application provides a viral or biomacromolecule detection device, a nanofluidic device, a high thermal-flux-density chip heat dissipation device, or a drug carrier comprising a nanotube-based nanochannel of the present application.
The nanotubes of the present application are not limited to the types of single or multi-walled carbon nanotubes and boron nitride nanotubes listed in the application documents, and other known and studied nanotubes, such as alumina nanotubes, zinc oxide nanotubes and polymer nanotubes, may be used in the present application with appropriate processing property verification.
The positive and negative photoresists of the present application are not limited to the types AZ 15004.4 cp and SU-82050 listed in the application, and other known and studied photoresists can be used in the present application with suitable process performance verification.
Has the advantages that:
the method has the advantages of high processing precision, simplicity in operation, high compatibility with the traditional technology, large designable space, high length-diameter ratio of the prepared nano channel, good uniformity and stability along the axis direction of the nano tube, capability of reducing the minimum size to 0.4nm, accurate and controllable size, good sealing property and difficulty in liquid leakage when the fluid medium moves along the nano channel. The application provides the possibility for people to explore material transportation in channels with smaller size and closer to an ideal model. The experimental result can be compared with the molecular dynamics simulation result under the same scale and verified mutually, is expected for a long time, and can greatly enrich the understanding and comprehension of people on the nano-scale material transportation.
For nouns and abbreviations in this application:
Si/SiO 2: silicon/silicon dioxide;
PDMS: polydimethylsiloxane (Polydimethylsiloxane) is a hydrophobic organic silicon material and is a common material for a flow channel of a microfluidic chip;
FIB: the ion beam is focused.
Drawings
Fig. 1 is a basic flow chart of the preparation method of the present application.
Figures 2-7 are 20000-fold magnified views of nanochannel 5nm diameter scanning electron microscopes made according to the methods of the present application.
Fig. 8 is a 100-fold three-dimensional imaging of a 5nm diameter nanochannel three-dimensional confocal microscope made according to the methods of the present application.
Fig. 9 is a photograph of a 5nm carbon nanotube nanofluidic chip prepared according to the method of the present application.
Detailed Description
EXAMPLE 1 basic Process for the preparation of Nanofluidic chips
The basic preparation process of the nano-fluidic chip comprises the following steps:
step one, in Si/SiO2Etching a mark on the chip;
step two, etching marked Si/SiO2Growing a carbon nano tube horizontal array on the wafer;
protecting a needed carbon nano tube by photoresist;
etching other redundant carbon nano tubes by using oxygen plasma;
constructing two independent SU-8 micro flow channels on the carbon nano tube by a photoetching method;
step six, breaking two ends of the carbon nano tube by using an FIB precise etching technology;
bonding a layer of pre-perforated PDMS on the upper surface of the SU-8 micro-flow channel;
step eight, inserting a liquid inlet pipe and a liquid outlet pipe at the reserved punching position, and inserting an electrode into the liquid outlet if electrical measurement is needed.
Example 2 Process for protecting desired carbon nanotubes by Photoresist
Glue homogenizing: the flow adopts AZ 15004.4 cp photoresist, and the rotating speed is set to be 500rpm for 10s and then 2000rpm for 30s in order to obtain the structure with the thickness of 1um by looking up a table.
Pre-baking: baking on a hot plate at 100 deg.C for 1 min.
Exposure: g line contact exposure for 5 s.
And (3) developing: the substrate was soaked in a water bath for 1min with AZ300MIF (2.38%).
Cleaning: rinse with deionized water for 30 s.
Example 3 Process for photo-lithographically building micro flow channels
Glue homogenizing: and (3) dripping SU-82050 photoresist on the substrate, and adsorbing the substrate on a spin coater to stand for a period of time. The table is looked up and the rotation speed is set to 500rpm for 10s, followed by 3000rpm for 30s in order to obtain a structure with a thickness of 50 um.
Pre-baking: baking on a hot plate at 65 deg.C for 4min, and baking at 95 deg.C for 9 min. A piece of filter paper was then placed in a large plastic petri dish and the hot silicon wafer was placed on the filter paper and allowed to cool to room temperature.
Exposure: the contact exposure machine was exposed for 20 s.
Post-baking: baking on a hot plate at 65 deg.C for 2min, and baking at 95 deg.C for 7 min. A piece of filter paper was then placed in a large plastic petri dish and the hot silicon wafer was placed on the filter paper and allowed to cool to room temperature.
And (3) developing: completely soaking a substrate to be developed in a developing solution for 7min, then spraying and washing the substrate with fresh developing solution for 10s, after the developing, using isopropanol to lightly wash and fix the substrate, and if white particles are generated after the substrate is placed in the isopropanol, the fact that the developing is insufficient, residual photoresist still exists and the developing and fixing steps need to be repeated is proved. Then, deionized water is used for thorough washing, and clean gas is used for blow-drying.
Cleaning: washing with deionized water for 1 min.
EXAMPLE 4 practical use of the method of the present application
We successfully constructed nanofluidic chips containing single 5nm carbon nanotube nanochannels using the methods described above in examples 1-3, as shown in fig. 2-7. The nanochannel of a single carbon nanotube is technically more difficult than a plurality of nanochannels. FIGS. 2-5 are enlarged views of the microchannel and nanochannel combination after completion of step five, and it is clear from the figures that a single nanochannel traverses both microchannels. Fig. 6-7 show that after step six, the part of the carbon nanotube exposed to the microchannel is broken, and a segment under the photoresist is retained, so as to connect two independent microchannels. FIG. 8 is a three-dimensional image of the micro flow channel under a three-dimensional confocal microscope before bonding PDMS to the micro flow channel. FIG. 9 is a pictorial photograph of the entire nanofluidic chip.
And then, carrying out leakage detection on the nano-fluidic chip, wherein the nano-fluidic chip constructed by the method is an experimental group, and then two control group chips are constructed. And the first control group is a chip in which the carbon nano tubes are not grown on the substrate by controlling the growth conditions in the second step, and the rest steps are kept unchanged, namely the first control group is a chip in which the carbon nano tubes are not grown on the substrate. And the second comparison group is a chip in which the two ends of the carbon nano tube are not broken by using an FIB precise etching technology in the sixth step, and the rest steps are kept unchanged, namely the second comparison group is a chip in which the carbon nano tube is not broken. And (3) carrying out a sealing test on the experimental group, the control group I and the control group II, wherein the introduced solution is a potassium chloride electrolyte solution, and by applying voltage, the current is only detected on the chip of the experimental group, and the current is not detected on the control group I and the control group II. The result shows that the chip prepared by the method has good sealing performance, only one fluid flow channel of the carbon nano tube exists, and other fluid flow channels do not exist.
We then use the constructed nanofluidic chip to study the transport of single-stranded DNA in the nanochannel, and systemize the motion law of single-stranded DNA molecules in the nanochannel, and the nanofluidic chip is expected to be applied to DNA sequencing and nucleic acid detection in the future.
Claims (10)
1. A nanotube-based nanochannel processing method, comprising:
firstly, etching a mark on a substrate;
growing a carbon nano tube horizontal array on the substrate with the etched mark;
protecting the required carbon nano tube by photoresist;
etching other redundant carbon nano tubes by using oxygen plasma;
constructing a micro-channel on the required carbon nano-tube by a photoetching method;
step six, breaking two ends of the carbon nano tube;
bonding a layer of pre-perforated PDMS on the upper surface of the micro flow channel;
step eight, inserting a liquid inlet pipe and a liquid outlet pipe at the reserved punching position.
2. The process of claim 1 wherein said substrate is Si/SiO2And (3) slicing.
3. The process of claim 1 or 2, wherein the nanotubes are carbon nanotubes or boron nitride nanotubes.
4. The process of claim 3, wherein said nanotubes are carbon nanotubes.
5. The process of claim 4 wherein step three uses a positive photoresist and step five uses a negative photoresist.
6. The process of claim 4 wherein in step six the ends of the carbon nanotubes are broken using FIB precision etching techniques.
7. The process of claim 4 wherein step eight comprises the step of inserting an electrode at the exit port.
8. A nanotube-based nanochannel produced using the processing method of any of claims 1-7.
9. Use of the process according to any one of claims 1 to 7 for the preparation of a viral or biomacromolecule detection device, a nanofluidic device, a high thermal-flux chip heat dissipation device or a pharmaceutical carrier.
10. A viral or biomacromolecule detection device, a nanofluidic device, a high thermal flux density chip heat dissipation device, or a drug carrier, comprising the nanotube-based nanochannel according to claim 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111537020.9A CN114177959A (en) | 2021-12-16 | 2021-12-16 | Preparation method of nano-fluidic chip based on carbon nano-tube |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111537020.9A CN114177959A (en) | 2021-12-16 | 2021-12-16 | Preparation method of nano-fluidic chip based on carbon nano-tube |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114177959A true CN114177959A (en) | 2022-03-15 |
Family
ID=80605167
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111537020.9A Pending CN114177959A (en) | 2021-12-16 | 2021-12-16 | Preparation method of nano-fluidic chip based on carbon nano-tube |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114177959A (en) |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040262636A1 (en) * | 2002-12-09 | 2004-12-30 | The Regents Of The University Of California | Fluidic nanotubes and devices |
| CN101175991A (en) * | 2005-05-17 | 2008-05-07 | 原子能委员会 | Microfluidic component with a channel filled with nanotubes and method for its production |
| CN101251532A (en) * | 2008-03-21 | 2008-08-27 | 浙江大学 | Method for manufacturing two-dimension nanometer channel of micro-noy flow control chip |
| CN101458260A (en) * | 2007-09-28 | 2009-06-17 | 原子能委员会 | Method of manufacturing a microfluid component comprising at least one microchannel filled with nanostructures |
| CN102010597A (en) * | 2010-09-26 | 2011-04-13 | 南京大学 | Preparation method of 2-D nano array tube |
| CN104401936A (en) * | 2014-12-19 | 2015-03-11 | 武汉大学 | Method for controlling growth of carbon nanotube bundle in horizontal direction of substrate |
| CN105609636A (en) * | 2016-02-17 | 2016-05-25 | 上海交通大学 | Field effect transistor employing directional single-walled carbon nanotube array as channel and manufacturing method |
| WO2016101697A1 (en) * | 2014-12-26 | 2016-06-30 | 江苏物联网研究发展中心 | Microfluidics surface enhanced raman scattering transparent device structure and preparation method thereof |
| CN110527296A (en) * | 2018-05-24 | 2019-12-03 | 厦门大学 | A kind of dynamic nano channel and its preparation, test method |
| CN112259608A (en) * | 2020-09-28 | 2021-01-22 | 中国电子科技集团公司第五十五研究所 | Carbon nanotube transistor using SiC-based material as substrate and method for manufacturing the same |
-
2021
- 2021-12-16 CN CN202111537020.9A patent/CN114177959A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040262636A1 (en) * | 2002-12-09 | 2004-12-30 | The Regents Of The University Of California | Fluidic nanotubes and devices |
| CN101175991A (en) * | 2005-05-17 | 2008-05-07 | 原子能委员会 | Microfluidic component with a channel filled with nanotubes and method for its production |
| CN101458260A (en) * | 2007-09-28 | 2009-06-17 | 原子能委员会 | Method of manufacturing a microfluid component comprising at least one microchannel filled with nanostructures |
| CN101251532A (en) * | 2008-03-21 | 2008-08-27 | 浙江大学 | Method for manufacturing two-dimension nanometer channel of micro-noy flow control chip |
| CN102010597A (en) * | 2010-09-26 | 2011-04-13 | 南京大学 | Preparation method of 2-D nano array tube |
| CN104401936A (en) * | 2014-12-19 | 2015-03-11 | 武汉大学 | Method for controlling growth of carbon nanotube bundle in horizontal direction of substrate |
| WO2016101697A1 (en) * | 2014-12-26 | 2016-06-30 | 江苏物联网研究发展中心 | Microfluidics surface enhanced raman scattering transparent device structure and preparation method thereof |
| CN105609636A (en) * | 2016-02-17 | 2016-05-25 | 上海交通大学 | Field effect transistor employing directional single-walled carbon nanotube array as channel and manufacturing method |
| CN110527296A (en) * | 2018-05-24 | 2019-12-03 | 厦门大学 | A kind of dynamic nano channel and its preparation, test method |
| CN112259608A (en) * | 2020-09-28 | 2021-01-22 | 中国电子科技集团公司第五十五研究所 | Carbon nanotube transistor using SiC-based material as substrate and method for manufacturing the same |
Non-Patent Citations (2)
| Title |
|---|
| 刘梦婉: ""基于纳米管的微纳流控芯片研究"", 《中国优秀硕士学位论文全文数据库》 * |
| 毛卫民: "《材料织构分析原理与检测技术》", 30 April 2008, 冶金工业出版社 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Xia et al. | Non-photolithographic methods for fabrication of elastomeric stamps for use in microcontact printing | |
| Duan et al. | Directed self-assembly at the 10 nm scale by using capillary force-induced nanocohesion | |
| Cabrini et al. | Nanofabrication handbook | |
| Zhou et al. | Chemically functionalized surface patterning | |
| Tian et al. | DNA nanostructures-mediated molecular imprinting lithography | |
| CN1615457A (en) | Patterning of solid state features by direct write nanolithographic printing | |
| Handrea-Dragan et al. | Multifunctional structured platforms: from patterning of polymer-based films to their subsequent filling with various nanomaterials | |
| Wang et al. | Dip-coating deposition on chemically patterned surfaces: A mechanistic analysis and comparison with topographically patterned surfaces | |
| Stokes et al. | Advances in lithographic techniques for precision nanostructure fabrication in biomedical applications | |
| CN109179313B (en) | Preparation method of micro-nanofluidic chip based on AFM | |
| CN114177959A (en) | Preparation method of nano-fluidic chip based on carbon nano-tube | |
| Wen et al. | Versatile approach of silicon nanofabrication without resists: Helium ion-bombardment enhanced etching | |
| Li et al. | Facile fabrication of flexible polymeric membranes with micro and nano apertures over large areas | |
| Lin et al. | Nickel electroplating for nanostructure mold fabrication | |
| Sun et al. | Fabrication of SU-8 photoresist micro–nanofluidic chips by thermal imprinting and thermal bonding | |
| Ghoshal et al. | Fabrication of Dimensional and Structural Controlled Open Pore, Mesoporous Silica Topographies on a Substrate | |
| Dhahi et al. | Polysilicon nanogap fabrication using a thermal oxidation process | |
| CN114534815B (en) | Nano-fluidic chip based on AFM (atomic force microscopy) scribing graphene and preparation method thereof | |
| KR101457185B1 (en) | Inserting method of polymer precusor into nano scale holes using vacuum effect and the precise replication method of nano pattern using thereof | |
| Punniyakoti et al. | Hydrogen Silsesquioxane‐Based Nanofluidics | |
| Lin et al. | New approaches of mold fabrication for nanoimprint lithography | |
| CN114829014B (en) | Nanoscale topography system for DNA sequencing and method of making same | |
| Hann et al. | Selective immobilization of 6HB and Tablet DNA origami Templates on microstructured surfaces by DLC and CF-polymer contrasting suitable for microfluidic integration | |
| Bowen | Stretchable Chemical Templates for the Manipulation of Droplets and the Fabrication of Functional Polymeric Microstructures | |
| Singh et al. | Laser direct writing of thick hybrid polymer microstructures |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |