CN-121991287-A - MAC intelligent window and preparation method thereof

Abstract

The invention relates to an intelligent window, in particular to an MAC intelligent window and a preparation method thereof. The invention develops a MAC intelligent window, which is based on an adhesion anti-freezing hydrogel electrolyte of a UCST mechanism and is combined with cesium tungsten bronze (Cs 0.33 WO 3 ) to form a novel intelligent window, so that the problem that the traditional thermochromic intelligent window cannot achieve energy conservation, privacy protection and long-term stability is effectively solved. The P (AM-co-AA) hydrogel has excellent adhesion performance, the optimal adhesion strength on glass can reach 0.43 MPa, and KCl endows the P (AM-co-AA) hydrogel with excellent freezing resistance, so that the MAC intelligent window has long-term stability and no obvious light transmittance fluctuation after 100 times of circulation. In outdoor tests, the MAC intelligent window shows excellent refrigerating performance, and compared with a common window, the MAC intelligent window has the maximum refrigerating effect of 3.2 ℃ and can save energy 163.82 MJ m ‑2 on average.

Inventors

• LIU LIBIN
• LIU HONGZHI
• Yu Wenmiao
• LU QINGQING
• MA FURUI

Assignees

• 齐鲁工业大学(山东省科学院)

Dates

Publication Date

20260508

Application Date

20250630

Claims (8)

1. 1. A MAC smart window is characterized in that the smart window structure consists of a glass sheet, P (AM-co-AA) hydrogel and cesium tungsten bronze Cs 0.33 WO 3 .
2. 2. A method for preparing the MAC smart window of claim 1, comprising the steps of: preparation of the hydrogel of step 1:P (AM-co-AA) Preparing P (AM-co-AA) hydrogel by adopting a free radical polymerization method, firstly dissolving acrylamide AM and acrylic acid AA in 10 g salt solutions with different concentrations according to different monomer proportions at room temperature, adding a cross-linking agent N, N-Methylene Bisacrylamide (MBA) accounting for 0.1-wt% of the total mass of the AM and the AA, stirring at room temperature to obtain a uniform aqueous solution, then injecting a photoinitiator alpha-ketoglutaric acid (KGA) accounting for 1wt% of the total mass of the AM and the AA into the obtained uniform aqueous solution, stirring until the mixture is completely dissolved to obtain a precursor solution, and finally injecting the precursor solution into a mould, and irradiating with Ultraviolet (UV); Step 2 preparation of Cs 0.33 WO 3 coated glass (glass-Cs 0.33 WO 3 ) Mixing Cs 0.33 WO 3 nano-particles with a mixed solution of acrylic resin and toluene according to the mass ratio of toluene to acrylic resin to Cs 0.33 WO 3 =0.9 to 0.85 to 0.16, and further stirring to obtain a uniform dispersion; step 3, assembling the MAC intelligent window And (2) injecting the precursor solution obtained in the step (1) into a mold composed of common glass and Cs 0.33 WO 3 coated glass with silicon rubber as a spacer, and then irradiating the assembled MAC intelligent window under Ultraviolet (UV) for crosslinking.
3. 3. The method according to claim 1, wherein in the step 1, the mass ratio of the acrylamide AM to the acrylic acid monomer is 9:1, 7:3, 5:5, 3:7, 1:9 respectively.
4. 4. The method according to claim 1, wherein in step 1, the salt solutions with different concentrations are potassium chloride solutions, and the concentrations are 0,1,2,3M.
5. 5. The method according to claim 1, wherein in step 1, ultraviolet light (UV) is irradiated by 10min (365 nm, 20W).
6. 6. The method according to claim 1, wherein in step 2, the depth of the coater recess is 22 μm.
7. 7. The method of claim 1, wherein in step 3, the silicone rubber has a thickness of 2mm.
8. 8. The method according to claim 1, wherein in step 3, the ultraviolet light (UV) is irradiated at 15 min (365 nm, 20W).

Description

MAC intelligent window and preparation method thereof Technical Field The invention relates to an intelligent window, in particular to an MAC intelligent window and a preparation method thereof. Background With the continuous increase of global energy consumption, the building energy consumption accounts for about 40% of the total global energy consumption. Windows are the least energy efficient components of building structures. In order to save energy as much as possible, intelligent windows are designed that can flexibly switch optical properties. Depending on the external stimulus, smart windows can be classified into thermochromic, electrochromic, mechanochromatic, and photochromic windows. The thermochromic window dynamically adjusts transparency through temperature change caused by sunlight, does not need additional energy input, is low in cost, and can effectively realize energy conservation. Currently, some thermochromic windows are mainly prepared based on inorganic thermochromic materials. However, the phase transition temperatures of these materials are generally higher than the conventional ambient temperature range, which limits their practical use under conventional climatic conditions. Thermochromic hydrogels are considered ideal candidates for smart windows due to their good transition temperature adjustability and low cost. However, the traditional hydrogel has weak adhesiveness and no freezing resistance, and greatly limits the application of the hydrogel in intelligent windows. Most thermochromic hydrogel smart windows today are based primarily on Low Critical Solution Temperature (LCST) mechanisms to achieve optical tuning. When the ambient temperature is higher, the intelligent window can become opaque to shield sunlight, so that the effect of adjusting the temperature is achieved. For example, smart windows based on PNIPAm hydrogels have achieved visible light transmittance (T lum) up to 91.3% and solar modulation capacity (Δt sol) of 88.84%. The PHPA smart window prepared by Zhu et al shows good solar energy modulation capability (1-93%) and fast photo response speed (from seconds to tens of seconds). However, such LCST smart windows may obstruct the transmission of natural sunlight in an opaque state during the daytime, resulting in additional illumination energy in the room and thus increased energy consumption. At the same time they become transparent at night (low ambient temperature) and cannot achieve privacy protection at night. In contrast, thermochromic hydrogels with an Upper Critical Solution Temperature (UCST) can meet these needs. The hydrogels remain transparent at high temperatures and become opaque at low temperatures. From a thermodynamic point of view, this phase separation phenomenon is determined by a change in the gibbs free energy (Δg m＝ΔHm-TΔSm). When Δg m >0, the system tends to phase separate. The difference between UCST and LCST is essentially due to the competing mechanism between enthalpy change (Δh m) and entropy change (Δs m) in gibbs free energy change. The LCST behavior is driven mainly by Δs m, tΔs m(ΔSm<0,-TΔSm > 0) term is dominant at high temperatures and increases sharply with increasing temperature. When |T delta S m | exceeds when i.DELTA.H2 m i, Δg m becomes positive and entropy driven phase separation occurs. Unlike LCST behavior, which is driven primarily by Δs m, UCST behavior is primarily caused by Δh m. at low temperature, the interaction between the polymer chains and water molecules is weak (Δh m >0, endothermic). The contribution of the T Δs m term is limited due to the low temperature, the phase transition being dominated by Δh m. When |Δh m | exceeds |tΔs m |, Δg m becomes positive, enthalpy driven phase separation occurs and the hydrogel becomes opaque. Therefore, unlike the conventional LCST hydrogel smart window, the UCST hydrogel smart window can satisfy the dual requirements of energy saving and privacy protection. For example, lai et al developed a bi-directional temperature sensitive smart window using Acrylamide (AM), acrylic Acid (AA) and N-isopropylacrylamide (NIPAM). This innovation has realized the energy-conservation and the privacy protection effect of smart window simultaneously. However, such smart windows have high transparency only in a specific temperature range, and have limitations in practical applications. Long and colleagues have also proposed a UCST smart window consisting of a Polyethylene (PE) sheet, UCST zwitterionic hydrogels, and silver nanowires (Ag NWs). The intelligent window not only can balance proper light transmittance and cooling effect in daytime, but also can provide privacy protection at night. However, the preparation process of Ag NWs is complicated and costly, and is not suitable for large-scale application. Meanwhile, the adhesion and freezing resistance of hydrogels in the smart windows are poor, and the insufficient adhesion and freezing resistance of hydrogels may cause deterio