作者：Jian Lu, Yu Zhang, Jing Li, Meifang Fu, Guoxiang Zou*, Shinji Ando, and Yongbing Zhuang*
關(guān)鍵字：polyimides, heat-insulating polymers, low-k dielectric materials
論文來源：期刊
具體來源：Macromolecules, https://doi.org/10.1021/acs.macromol.2c02148
發(fā)表時間：2023年
隨著5G時代的到來，電子產(chǎn)品向高頻高速數(shù)字信號傳輸方向發(fā)展，集成電路的小型化和集成化使得芯片尺寸越來越小。隨著芯片內(nèi)部組件間的距離逐漸縮小，信號傳輸?shù)难舆t使得芯片的性能大大降低。作為集成電路主要的絕緣材料，常規(guī)PI薄膜的介電常數(shù)在3.0~3.5范圍內(nèi)，愈來愈無法滿足高頻率集成電路的性能要求。
高溫隔熱材料（薄膜或泡沫）在航空航天、建筑、阻燃和防火領(lǐng)域具有廣泛的應用，例如用于儲存和長途運輸氫氣或稀有氣體的隔熱薄膜和泡沫，其市場規(guī)模正在不斷擴大。高性能隔熱材料應具有良好的機械強度、低導熱性、低密度和優(yōu)異的耐高溫和低溫性。例如，消防設備要求重量輕、隔熱性好，從而減輕消防設備的重量，這將提高消防設備的性能和消防操作的成功率。PI基的隔熱材料因其輕質(zhì)、良好的機械和耐熱性能等優(yōu)點而備受關(guān)注。然而，傳統(tǒng)的PI膜的面外導熱系數(shù)為0.1-0.5 W/（mK），隔熱和保溫性能有待提高。
朝格爾堿基（Tro?ger’s base (TB)）是剛性的v形橋聯(lián)雙環(huán)連接基團，研究人員將其引入到聚酰亞胺（PI）主鏈中，制備了基于TB的聚酰亞胺（PI-TB-B和PI-TB-P)，調(diào)查了PI的結(jié)構(gòu)和性能（包括折射率、面內(nèi)/外雙折射、透明性、導熱系數(shù)和介電性能等，構(gòu)建了PI的分子結(jié)構(gòu)與導熱系數(shù)和介電性質(zhì)（低頻率（1 kHz~1MHz）和高頻（10 GHz）條件）等物理性質(zhì)之間的相關(guān)性。TB基PI膜在10GHz下表現(xiàn)出低介電常數(shù)（Dk＝2.25-2.80）。特別地，PI-TB-N在10GHz下顯示出超低的Dk＝2.25，這低于商業(yè)化Kapton（PMDA-ODA，Dk＞3.5）、6FDA基（Dk＝2.37-2.95）、BPADA基（Dk=2.83-3.18）、酯基（Dk=2.44-3.26）PI和其他低介電聚合物，包括聚醚（PES，Dk≈2.4），聚（亞苯基醚）（PPEs，Dk＝2.4-2.6）和苯并環(huán)丁烯（BCB）基聚合物（Dk＝2.6-2.8）等。
另外，這些PI也表現(xiàn)優(yōu)異的隔熱性，與商業(yè)聚酰亞胺膜 Kapton（0.240 W/mK）相比，它們具有超低的導熱系數(shù)（λ＝0.035-0.145 W/m K）。所有TB基PI膜的λ值均低于0.145W/（mK），遠低于商業(yè)Kapton（PMDA-ODA，λ=0.16-0.25W/（mK）（文獻）和λ=0.240W/（mK）（本研究））以及其他報道的PI膜（λ=0.15-0.26W/（mK）的導熱系數(shù)。值得一提的是，其中，PI-TB-P顯示出超低的λ值（0.035W/（mK）），僅為商業(yè)膜 Kapton的1/8，這是迄今為止報道的所有PI薄膜中最低的λ值，表明TB基的PI膜作為隔熱材料的潛在應用前景。
研究還結(jié)合PI分子結(jié)構(gòu)參數(shù)的計算，系統(tǒng)考察了將TB結(jié)構(gòu)引入PI主鏈對聚集態(tài)結(jié)構(gòu)和物理性質(zhì)的影響。這項工作為隔熱和低介電PI材料的分子結(jié)構(gòu)設計提供了新的思路。
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隨著5G時代的到來，電子產(chǎn)品向高頻高速數(shù)字信號傳輸方向發(fā)展，集成電路的小型化和集成化使得芯片尺寸越來越小。隨著芯片內(nèi)部組件間的距離逐漸縮小，信號傳輸?shù)难舆t使得芯片的性能大大降低。作為集成電路主要的絕緣材料，常規(guī)PI薄膜的介電常數(shù)在3.0~3.5范圍內(nèi)，愈來愈無法滿足高頻率集成電路的性能要求。
高溫隔熱材料（薄膜或泡沫）在航空航天、建筑、阻燃和防火領(lǐng)域具有廣泛的應用，例如用于儲存和長途運輸氫氣或稀有氣體的隔熱薄膜和泡沫，其市場規(guī)模正在不斷擴大。高性能隔熱材料應具有良好的機械強度、低導熱性、低密度和優(yōu)異的耐高溫和低溫性。例如，消防設備要求重量輕、隔熱性好，從而減輕消防設備的重量，這將提高消防設備的性能和消防操作的成功率。PI基的隔熱材料因其輕質(zhì)、良好的機械和耐熱性能等優(yōu)點而備受關(guān)注。然而，傳統(tǒng)的PI膜的面外導熱系數(shù)為0.1-0.5 W/（mK），隔熱和保溫性能有待提高。
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隨著5G時代的到來，電子產(chǎn)品向高頻高速數(shù)字信號傳輸方向發(fā)展，集成電路的小型化和集成化使得芯片尺寸越來越小。隨著芯片內(nèi)部組件間的距離逐漸縮小，信號傳輸?shù)难舆t使得芯片的性能大大降低。作為集成電路主要的絕緣材料，常規(guī)PI薄膜的介電常數(shù)在3.0~3.5范圍內(nèi)，愈來愈無法滿足高頻率集成電路的性能要求。
高溫隔熱材料（薄膜或泡沫）在航空航天、建筑、阻燃和防火領(lǐng)域具有廣泛的應用，例如用于儲存和長途運輸氫氣或稀有氣體的隔熱薄膜和泡沫，其市場規(guī)模正在不斷擴大。高性能隔熱材料應具有良好的機械強度、低導熱性、低密度和優(yōu)異的耐高溫和低溫性。例如，消防設備要求重量輕、隔熱性好，從而減輕消防設備的重量，這將提高消防設備的性能和消防操作的成功率。PI基的隔熱材料因其輕質(zhì)、良好的機械和耐熱性能等優(yōu)點而備受關(guān)注。然而，傳統(tǒng)的PI膜的面外導熱系數(shù)為0.1-0.5 W/（mK），隔熱和保溫性能有待提高。
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The correlations between the molecular structures of
four Tro?ger’s base (TB)-based polyimides (PIs) and two non-TB
containing analogues and physical properties including thermal conductivity (λ) and dielectric
properties both at low- and high-frequencies were investigated in detail. The
TB-based PI films exhibited low dielectric constants (Dk=2.25-2.80)
at 10 GHz. They possessed much lower λ values (0.035-0.145 W/mK) compared to the
commercial PI Kapton (0.240 W/mK). The influences of incorporating TB units into chain backbones on
aggregation structures and physical properties of PIs were identified. Incorporating TB units into chain backbones
effectively reduced the degree of chain orientation and increased fractional
free volume, leading to both low Dk and low λ values for the resulting PI films. Also,
introducing TB units enhanced molecular weights, toughness, and
glass-transition temperature (Tg) of the resulting
PIs. Therefore, the TB-based PIs can be promising as heat-insulating and low-k
dielectric materials.
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The correlations between the molecular structures of
four Tro?ger’s base (TB)-based polyimides (PIs) and two non-TB
containing analogues and physical properties including thermal conductivity (λ) and dielectric
properties both at low- and high-frequencies were investigated in detail. The
TB-based PI films exhibited low dielectric constants (Dk=2.25-2.80)
at 10 GHz. They possessed much lower λ values (0.035-0.145 W/mK) compared to the
commercial PI Kapton (0.240 W/mK). The influences of incorporating TB units into chain backbones on
aggregation structures and physical properties of PIs were identified. Incorporating TB units into chain backbones
effectively reduced the degree of chain orientation and increased fractional
free volume, leading to both low Dk and low λ values for the resulting PI films. Also,
introducing TB units enhanced molecular weights, toughness, and
glass-transition temperature (Tg) of the resulting
PIs. Therefore, the TB-based PIs can be promising as heat-insulating and low-k
dielectric materials.