CN-122017289-A - Preparation method of hydrated salt phase-change hydrogel atomic force microscope sample

Abstract

The invention discloses a preparation method of a hydrated salt phase-change hydrogel atomic force microscope sample. The method comprises the steps of dripping a hydrogel polymer material into a quartz glass ring with a newly-cleaved mica sheet at the bottom, immediately irradiating under ultraviolet light to perform photo-curing crosslinking to obtain a hydrogel sheet, cooling the hydrogel sheet to room temperature to obtain an atomic force microscope sample to be detected, reversely tearing off the mica sheet from the quartz glass ring, and performing subsequent microstructure characterization within 20 min. The method solves the problem that AFM characterization lacks ‌ standardized hydrogel preparation methods, is easy to operate, can ensure that a sample is kept stable within 24 hours while a flat detection surface is formed, can obtain high-resolution characterization of microscopic morphology, quantitative height and mechanical property of the sample surface, improves the accuracy of sample characterization, and ensures the stability and reliability of a test result.

Inventors

• SHEN YUE
• ZHANG SHENGDI
• ZHANG SHUAISHUAI
• Bai wandong
• GENG ZHANLI
• LI XIANG
• ZENG JINBO
• REN XIUFENG
• ZHAO BINYU

Assignees

• 中国科学院青海盐湖研究所

Dates

Publication Date

20260512

Application Date

20260401

Claims (10)

1. 1. A method for preparing a hydrated salt phase-change hydrogel atomic force microscope sample, which is characterized by comprising the following steps: S1, heating, stirring and melting the hydrated salt system phase-change material in a sealing state to obtain a molten hydrated salt system phase-change material; s2, sequentially adding a monomer, a cross-linking agent and an initiator into the phase change material of the molten hydrated salt system according to a certain mass ratio, and heating and stirring in a sealed state to obtain a polymer; S3, taking a certain amount of the polymer, dripping the polymer into a quartz glass ring with a flat substrate at the bottom, and immediately irradiating the quartz glass ring with ultraviolet light for photo-curing and crosslinking to obtain a hydrogel sheet; And S4, cooling the hydrogel sheet to room temperature to obtain an atomic force microscope sample to be detected, reversely tearing off the quartz glass ring, and then carrying out subsequent microstructure characterization.
2. 2. The method for preparing a hydrated salt phase-change hydrogel atomic force microscope sample according to claim 1, wherein the flat substrate is selected from one of a freshly cleaved mica sheet, a silicon oxide sheet, and a glass slide.
3. 3. The method of preparing a hydrated salt phase-change hydrogel atomic force microscope sample of claim 1, wherein the planar substrate is selected from freshly cleaved mica flakes.
4. 4. The method for preparing a hydrated salt phase-change hydrogel atomic force microscope sample according to claim 1, wherein in step S3, the polymer thickness is lower than the height of the quartz glass ring, preventing the sample from overflowing.
5. 5. The method for preparing a hydrated salt phase-change hydrogel atomic force microscope sample according to claim 1, wherein the step S3 is characterized in that the photo-curing crosslinking is performed by irradiation under ultraviolet light, specifically by irradiation under 365nm ultraviolet light for 3-7 min.
6. 6. The preparation method of the hydrated salt phase-change hydrogel atomic force microscope sample according to claim 1, wherein the mass ratio of the monomer to the cross-linking agent is 100 (1-5), and the initiator is 1% -2% of the mass of the monomer.
7. 7. The method for preparing a hydrated salt phase-change hydrogel atomic force microscope sample according to claim 1, wherein the monomer is selected from one of acrylamide and acrylic acid.
8. 8. The method for preparing a hydrated salt phase-change hydrogel atomic force microscope sample according to claim 1, wherein the cross-linking agent is selected from one of polyethylene glycol diacrylate and N, N' -methylenebisacrylamide.
9. 9. The method for preparing a hydrated salt phase-change hydrogel atomic force microscope sample according to claim 1, wherein the initiator is selected from one of 1-hydroxycyclohexyl phenyl ketone and 2, 2-diethoxyacetophenone.
10. 10. Use of the preparation method according to any one of claims 1 to 9 for atomic force microscopy of the microscopic morphology of hydrated brine gel materials.

Description

Preparation method of hydrated salt phase-change hydrogel atomic force microscope sample Technical Field The invention relates to the technical field of atomic force microscope samples, in particular to a preparation method of a hydrated salt phase-change hydrogel atomic force microscope sample. Background The hydrated salt phase-change hydrogel is used as a novel intelligent thermal management material, and the synergistic optimization of latent heat storage and structural stability is realized by compounding ‌ hydrated salt phase-change material ‌ (such as Na 2SO4·10H2O、CaCl2·6H2O、CH3COONa·3H2 O and the like) with ‌ three-dimensional polymer network ‌ (such as PVA and polyacrylamide). The thermal regulation mechanism depends on reversible crystallization/melting phase change of hydrated salt, and the hydrogel network effectively inhibits the leakage and phase separation of the salt through physical confinement and chemical bonding. At present, the microstructure characterization of the hydrated salt phase-change hydrogel generally adopts an electron microscopy technology, such as a Scanning Electron Microscope (SEM) or a Transmission Electron Microscope (TEM), the conventional electron microscopy technology faces a remarkable technical bottleneck, but the high vacuum mode of the SEM leads to irreversible dehydration of the hydrated salt, so that microstructure collapse and phase-change function degradation are caused, and an organic matrix (such as polyvinyl alcohol PVA) is easy to generate artifacts such as melting, hole formation and the like under electron irradiation to influence data reliability, and although a freeze electron microscope (Cryo-SEM) can keep the original distribution state of the hydrated salt crystals in a gel network through freeze drying and realize direct observation of a phase-change interface, the method relies on a helium circulation refrigerating system, so that the equipment cost is high and the sample preparation is complex. And salt crystals are easy to dissolve in the sample preparation process of the TEM ultrathin section, and the hydrogel network is crosslinked and degraded by electron beam irradiation. In comparison, the Atomic Force Microscope (AFM) can break through the above limitation by virtue of the liquid phase environment compatibility ‌ of the ‌ nm-scale in-situ analysis capability ‌ and ‌, and can nondestructively characterize a water sample without vacuum or freezing, and synchronously acquire multidimensional information of morphology, surface height and mechanical properties. However, the lack of ‌ standardized hydrogel preparation method ‌ for AFM characterization in the prior art restricts the popularization and application of the technology. Therefore, developing a sample preparation scheme of ‌ which is simple, quick and repeatable ‌, and realizing AFM suitability optimization of hydrated salt phase-change gel, has become a key problem to be solved urgently in the field of current phase-change material characterization. Disclosure of Invention In view of the defects of the prior art, the invention aims to provide a preparation method of a hydrated salt phase-change hydrogel atomic force microscope sample, which aims at the defects that the resolution is low, the sample is easy to change, or the equipment cost is high due to sample freeze drying operation and helium circulation refrigerating system is required when the existing electron microscope characterizes the hydrated salt phase-change hydrogel, and provides a preparation method of an AFM sample in a quartz glass ring with a newly cleaved mica sheet at the bottom. The technical scheme of the invention is as follows: The invention provides a preparation method of a hydrated salt phase-change hydrogel atomic force microscope sample, which is characterized by comprising the following steps of: S1, heating, stirring and melting the hydrated salt system phase-change material in a sealing state to obtain a molten hydrated salt system phase-change material; s2, sequentially adding a monomer, a cross-linking agent and an initiator into the phase change material of the molten hydrated salt system according to a certain mass ratio, and heating and stirring in a sealed state to obtain a polymer; S3, taking a certain amount of the polymer, dripping the polymer into a quartz glass ring with a flat substrate at the bottom, and immediately irradiating the quartz glass ring with ultraviolet light for photo-curing and crosslinking to obtain a hydrogel sheet; And S4, cooling the hydrogel sheet to room temperature to obtain an atomic force microscope sample to be detected, reversely tearing off the quartz glass ring, and then carrying out subsequent microstructure characterization. Preferably, the flat substrate is selected from one of a newly cleaved mica sheet, a silicon oxide sheet, and a glass slide. More preferably, the planar substrate is selected from newly cleaved mica flakes. The "newly cleaved mica flakes"