【摘要】：Janus粒子由于其具有物理或化學(xué)不對(duì)稱的特點(diǎn),物理形態(tài)上例如雪人狀、蘑菇狀Janus粒子,化學(xué)性質(zhì)例如粒子的表面親疏水性,近年來環(huán)境敏感型Janus粒子受到各科研工作者廣泛關(guān)注。Janus粒子的制備方法有很多,其中Pickering乳液法由于其操作簡(jiǎn)便、能大量制備,后處理簡(jiǎn)單的特點(diǎn)被大量使用在科研實(shí)驗(yàn)中。本研究利用Pickering乳液法制備了半草莓型SiO2 Janus粒子。其原理是利用氨基修飾的大粒徑SiO2微球穩(wěn)定石蠟-水乳液,石蠟冷卻后SiO2微球部分嵌在石蠟里,通過酰胺反應(yīng)對(duì)SiO2表面進(jìn)行親疏水不對(duì)稱改性,洗脫下來后與環(huán)氧修飾的小粒徑Si02微球與Fe3O4@SiO2微球通過氨基與環(huán)氧基自組裝得到半草莓型Janus粒子。其中Si02微球、Fe3O4與Fe3O4@SiO2為球形,且粒徑大小均勻,SiO2微球粒徑隨氨水量的增加而增加;Fe3O4的形態(tài)可由油酸鈉調(diào)控;Fe3O4@SiO2的粒徑可以通過調(diào)節(jié)TEOS來調(diào)控;由于Fe3O4單位質(zhì)量含量減少與SiO2包覆層的屏蔽作用,與Fe3O4的磁飽和強(qiáng)度相比,Fe3O4@SiO2與Janus粒子都有大幅度下降。通過XPS證實(shí)了 Janus粒子的形成作用為氨基與環(huán)氧基自組裝。為了構(gòu)建自驅(qū)動(dòng)馬達(dá),本研究結(jié)合物理濺鍍法與化學(xué)聚合法,制備了既有催化作用又有溫敏特性的P(MAA-co-DVB)@Pt@PNIPAM Janus粒子。將Janus粒子與H2O2溶液一起構(gòu)建自驅(qū)動(dòng)馬達(dá),Janus粒子在25℃下的運(yùn)動(dòng)速率明顯高于40℃下的運(yùn)動(dòng)速率;Janus粒子在30%H2O2溶液中的運(yùn)動(dòng)速率是10%H2O2溶液中的6倍。
[Abstract]:Janus particles are characterized by physical or chemical asymmetries, such as snowman, mushroom Janus, and chemical properties such as surface hydrophobicity. In recent years, environment-sensitive Janus particles have been widely concerned by researchers. There are many methods for the preparation of Janus particles, among which Pickering emulsion method is widely used in scientific research experiments because of its simple operation and large amount of preparation. In this study, half strawberry SiO2 Janus particles were prepared by Pickering emulsion method. The principle is to stabilize the paraffin-water emulsion with large diameter SiO2 microspheres modified by amino groups. The SiO2 microspheres are partially embedded in paraffin after paraffin wax cooling, and the hydrophilic asymmetric modification of SiO2 surface is carried out by amide reaction. After elution, small diameter Si02 microspheres and Fe3O4@SiO2 microspheres modified with epoxy were prepared by amino and epoxide self-assembly to obtain semi-strawberry Janus particles. Among them, Si02 microspheres, Fe3O4 and Fe3O4@SiO2 were spherical, and the size of SiO2 microspheres was uniform. The size of SiO2 microspheres increased with the increase of ammonia water content, the morphology of Fe3O4 was regulated by sodium oleate, the particle size of Fe3O4@SiO2 could be regulated by adjusting TEOS. Due to the decrease of Fe3O4 unit mass content and the shielding effect of SiO2 cladding, both Fe3O4@SiO2 and Janus particles have a significant decrease compared with the magnetic saturation intensity of Fe3O4. The formation of Janus particles was confirmed by XPS as self-assembly of amino and epoxy groups. In order to construct a self-driving motor, P (MAA-co-DVB) @ Pt@PNIPAM Janus particles with both catalytic and temperature-sensitive properties were prepared by physical splashing and chemical polymerization. The self-driving motor was constructed by combining Janus particles with H2O2 solution. The moving rate of Janus particles at 25 鈩，

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