本文選題：相變 + 介電異樣　； 參考：《東南大學(xué)》2017年碩士論文

【摘要】：相變材料特別是鐵電材料是一類應(yīng)用前景廣闊的功能材料,其在信息存儲、通訊、紅外探測以及壓電傳感等方面的重要應(yīng)用而受到了人們的廣泛關(guān)注。晶體的相變過程常常伴隨著結(jié)構(gòu)和對稱性的改變,同時在相變點附近,會出現(xiàn)明顯的介電性、熱力學(xué)性質(zhì)等相關(guān)物理性質(zhì)的異常變化。特別是有機-無機雜化材料,它因為同時擁有有機化合物和無機化合物的優(yōu)點,具備結(jié)構(gòu)可控性且性能穩(wěn)定,在實際的應(yīng)用中表現(xiàn)出非常良好的性質(zhì),是目前相變材料領(lǐng)域的研究熱點之一。為了尋找新的相變材料,我們設(shè)計并合成了基于三甲基膦衍生物和螺環(huán)胺的多種新型有機-無機雜化物,并通過晶體結(jié)構(gòu)分析、介電測量和差示掃描量熱分析(DSC)方面研究了其發(fā)生相變的可能性。本文以三甲基膦和三乙基膦衍生物為配體合成了6種化合物:[(CH3)3PCH2CH2P(CH3)3][ZnBr4](1)、[(CH3)3PCH2CH2P(CH3)3][MnN3C3S3OH]·2H20(2)、[(CH2CH3)3PCH2CH2P(CH2CH3)3][CuBr4](3)、[(CH2CH3)3PCH2CH2P-(CH2CH3)3]2[Cd3C8N12Br6](4)、[(CH3)3P(CH2)4P(CH3)3][CdBr4](5)、[(CH3)3P-(CH2)4P(CH3)3][Cd(SCN)3]2(6);以含胺陽離子的三甲基膦衍生物及冠醚為配體合成了4種化合物:[(CH3)3PCH2CH2CH2NH3][PbBr4](7)、[(CH3)3PCH2CH2CH2-NH3][CdI4](8)、[C12H2406][(CH3)3PCH2CH2CH2NH3][CdBr4](9)、[C12H2406][(CH3)3PCH2CH2CH2NH3][ZnBr4](10);以吡咯烷的衍生物為配體合成2種化合物:[(CH2)4N(CH2)4]2[ZnBr4](11)、[(CH2)4N(CH2)4]2[CdBr4](12)。同時分別對這12種物質(zhì)的紅外、粉末衍射、晶體結(jié)構(gòu)及介電性質(zhì)進行了表征和分析。實驗結(jié)果表明:化合物2,3,10在低溫區(qū)出現(xiàn)了階梯狀的介電異樣,又通過DSC測試觀察到相變點附近有明顯的放熱峰和吸熱峰的出現(xiàn),進一步證實了這三種化合物在低溫相發(fā)生了可逆的結(jié)構(gòu)相變�；衔�6,11,12在高溫區(qū)出現(xiàn)了平臺狀的介電異樣,同樣通過DSC分析證實了可逆相變的發(fā)生,接著對化合物6和12的高溫結(jié)構(gòu)的分析可知,化合物6發(fā)生結(jié)構(gòu)相變是由于有機膦鹽的陽離子在高溫時的完全無序以及陰離子一維鏈[Cd(SCN)3-]n的變形運動造成的,而化合物12是因為具有柔性結(jié)構(gòu)的螺環(huán)銨陽離子構(gòu)象的變化以及陰離子的再定位引起的。其余的化合物在降溫和升溫的過程中沒有出現(xiàn)可逆的介電異樣峰,初步判定可能沒有發(fā)生結(jié)構(gòu)相變。
[Abstract]:Phase change materials, especially ferroelectric materials, are a kind of functional materials with broad application prospects. Their important applications in information storage, communication, infrared detection and piezoelectric sensing have attracted extensive attention. The phase transition process of crystals is often accompanied by changes in structure and symmetry. At the same time, there will be obvious abnormal changes in physical properties such as dielectric properties, thermodynamic properties and other related physical properties near the phase transition point. In particular, organic-inorganic hybrid materials, because of the advantages of both organic and inorganic compounds, have structural controllability and stable performance, and have shown very good properties in practical applications. It is one of the research hotspots in the field of phase change materials. In order to find new phase change materials, we have designed and synthesized several novel organic-inorganic hybrids based on trimethyl phosphine derivatives and spirocyclic amines, and analyzed their crystal structure. The possibility of phase transition was studied in dielectric measurement and differential scanning calorimetry (DSC). 鏈枃浠ヤ笁鐢插熀鑶﹀拰涓変箼鍩鴻啨琛嶇敓鐗╀負閰嶄綋鍚堟垚浜，

本文編號：2028276