范鵬,金倫,羅芳華,陳國華
?
石墨烯納米復(fù)合涂層在纖維織物表面的制備與應(yīng)用進(jìn)展
范鵬1,金倫2,羅芳華1,陳國華1
(1.華僑大學(xué) 材料科學(xué)與工程學(xué)院,福建 廈門 361021;2.福建華峰新材料有限公司 福建省運(yùn)動(dòng)鞋面料重點(diǎn)實(shí)驗(yàn)室,福建 莆田 351144)
石墨烯因其導(dǎo)電性能優(yōu)異、比表面積大、楊氏模量高等獨(dú)特性能受到科研人員的廣泛關(guān)注,將石墨烯應(yīng)用于纖維表面改性以賦予纖維織物導(dǎo)電、紫外線防護(hù)、電磁屏蔽等性能,是目前的主要研法目標(biāo)。以石墨烯基復(fù)合涂層纖維織物制得的材料在醫(yī)療器械,電子器件,傳感器領(lǐng)域都呈現(xiàn)巨大的應(yīng)用前景。從機(jī)理、制備方法、性能與應(yīng)用等三個(gè)方面介紹了石墨烯基納米復(fù)合涂層,并闡述了石墨烯基納米復(fù)合涂層的作用機(jī)理。歸納了石墨烯納米復(fù)合涂層纖維與織物的制備方法,其中,浸漬法具有操作簡便、污染小、耗能小、重復(fù)性好等優(yōu)勢,且通過殼聚糖、牛血清蛋白、聚氨酯等方法改性纖維織物表面,能增強(qiáng)石墨烯涂層與基底牢固性,提高石墨烯基納米復(fù)合涂層的綜合性能??偨Y(jié)了石墨烯基納米復(fù)合涂層纖維與織物在電磁屏蔽材料、疏水材料、柔性電極、超級電容、傳感器等方面的應(yīng)用研究現(xiàn)狀,并對其發(fā)展進(jìn)行了展望。
石墨烯;涂層;纖維;柔性電極;導(dǎo)電織物;傳感器
2004年,Geim和Novoselov[1]首次報(bào)道了通過微機(jī)械剝離法獲得單層石墨烯,揭示了石墨烯的特殊物理性質(zhì),并獲得2010年的諾貝爾物理學(xué)獎(jiǎng)。這一研究成果引起世界各地科學(xué)家和研究學(xué)者的廣泛關(guān)注。針對石墨烯在各個(gè)領(lǐng)域的研究正如火如荼地開展。目前,將石墨烯運(yùn)用于紡織領(lǐng)域并賦予其纖維導(dǎo)電性[2]、電磁屏蔽[3]、疏水性[4]、阻燃[5]等特殊性能已成為新的熱點(diǎn),具有廣闊的發(fā)展前景。本文對石墨烯納米復(fù)合涂層纖維的作用機(jī)理、制備方法、性能和應(yīng)用進(jìn)行綜述,為制備多功能復(fù)合石墨烯基納米復(fù)合涂層織物提供一定的借鑒。
碳原子擁有多樣的雜化狀態(tài)(sp2、sp3),不同的雜化狀態(tài)賦予碳不同的形態(tài),石墨烯是一種由單層或少層的碳原子緊密堆積排列,具有二維蜂窩狀結(jié)構(gòu)的新材料,原子間以共價(jià)鍵形式進(jìn)行連接。通過sp2-sp2雜化形式構(gòu)成穩(wěn)定的六邊形平面結(jié)構(gòu),碳原子上的p軌道通過肩并肩的形式構(gòu)成離域大π鍵,使石墨烯在室溫下有很高的電子流動(dòng)性(2.5×105cm2·V?1·s?1)。石墨烯還具有高導(dǎo)熱性(3000 W·m?1·K?1)、高強(qiáng)度(130 GPa)、高拉伸模量(1 TPa)、極大比表面積(2630 cm2/g)[6]等優(yōu)異性能。利用石墨烯作為纖維涂層,可使纖維的導(dǎo)電性具有很大的提升空間,還可以通過修飾等手段實(shí)現(xiàn)纖維的多功能化。
一般,石墨烯片層表面無活性官能團(tuán),其分散液易團(tuán)聚、沉降[7],結(jié)構(gòu)規(guī)整的石墨烯化學(xué)活性低,與纖維基體相容性差、作用力小,簡單涂附在纖維表面會(huì)出現(xiàn)涂附不均勻、易脫落等問題。將石墨氧化為氧化石墨烯(GO)制備成溶液涂附于纖維上,再還原為石墨烯涂層,可以在很大程度上解決這一問題[8]。
石墨在強(qiáng)酸性環(huán)境下會(huì)氧化,氧化過程中表面引入羧基、羥基等含氧基團(tuán),這些含氧基團(tuán)會(huì)破壞石墨的共軛結(jié)構(gòu),減弱片層間的范德華力,并與水分子形成氫鍵,使氧化石墨烯能夠充分分散于水溶液中[9]。此外,氧化石墨烯表面帶負(fù)電荷,與纖維上帶正電荷的官能團(tuán)相互作用,從而吸附在纖維表面。氧化石墨烯自身共軛結(jié)構(gòu)被破壞,不具有導(dǎo)電性,但還原過程中由于大部分含氧基團(tuán)被去除,共軛結(jié)構(gòu)被修復(fù),因此還原氧化石墨烯(RGO)具有一定的導(dǎo)電性。
不同還原方法對制備石墨烯基復(fù)合涂層纖維的導(dǎo)電性有一定的影響。還原方法主要分為兩大類—化學(xué)還原和物理還原?;瘜W(xué)還原法所用的還原劑主要有抗壞血酸[10-11]、肼[12-13]、連二亞硫酸鈉[14-15]、氫碘酸[16]、檸檬酸鹽[17]、氫氧化銨[18]、硫酸亞鐵[19]、氯化亞錫[20]等。物理還原法有熱還原[21-22]、電化學(xué)還 原[23-24]、紫外線還原[25]、微波還原[26]等。物理還原最大的優(yōu)點(diǎn)是還原時(shí)不需要接觸樣品,不引入新的化學(xué)物質(zhì),保證了產(chǎn)物的純凈性。但在還原過程中,需要注意纖維的狀態(tài),防止損壞樣品。而在熱還原法中,通常必須在惰性氣體中進(jìn)行反應(yīng)[21],電化學(xué)還原需將物品放進(jìn)可導(dǎo)電的基底中進(jìn)行還原[23]。
制備石墨烯基復(fù)合纖維主要方法有浸漬法,即將纖維浸入氧化石墨烯(或石墨烯)溶液,一段時(shí)間后取出干燥,再還原得到石墨烯基復(fù)合涂層纖維。也可將涂層纖維制成織物,賦予織物電磁屏蔽、紫外線屏蔽等特殊功能。這種方法比起氣相沉積(CVD法)[27]、電化學(xué)沉積[27]、真空過濾[29]、電泳[30]等方法,有著操作簡便、污染少、耗能小等優(yōu)勢。通常氧化石墨烯或石墨烯能夠很好地包覆纖維。如圖1所示,這是一個(gè)典型的氧化石墨烯包覆纖維的過程。氧化石墨烯在靜電作用下聚集到纖維表面,一層一層緊密包覆纖維,最后進(jìn)行還原,還原前呈褐色,還原后呈深黑色。
浸漬法對基體材料的選擇也有一定的要求:用羊毛等纖維進(jìn)行涂附,纖維本身具有大量的活性基團(tuán),與氧化石墨烯結(jié)合能力強(qiáng);用芳綸等纖維進(jìn)行涂附,纖維表面則呈現(xiàn)較大的惰性,反應(yīng)活性低,需要對纖維進(jìn)行改性處理,改善纖維與氧化石墨烯的界面結(jié)合狀況。下面是一些常見的纖維改性處理方法。
殼聚糖是甲殼素脫N-乙?;漠a(chǎn)物,含有大量氨基與羥基。一方面,氨基、羥基與氧化石墨烯中含氧基團(tuán)形成氫鍵,增強(qiáng)結(jié)合能力;另一方面,殼聚糖中的氨基使其表面帶正電荷,與氧化石墨烯產(chǎn)生靜電作用,提高涂附牢固度。
Pan等人[32]利用殼聚糖作為粘附劑和分散劑,通過LBL組裝法(層層自組裝法),使其沉積在棉織物上,得到了一種新的防火材料,在垂直火焰測試中呈現(xiàn)出自熄滅的性質(zhì)。Tian等人[33]利用石墨烯/3.4-聚乙烯二氧噻吩(PEDOT)/聚苯乙烯磺酸鈉(PSS)/甲殼素(CS)制備高導(dǎo)電、抗紫外線多功能織物。如圖2所示,在帶正電的棉織物上沉積帶負(fù)電的聚苯乙烯磺酸/石墨烯(PG),干燥后沉積帶正電的殼聚糖(CS),重復(fù)以上操作,獲得了導(dǎo)電性高效和強(qiáng)防護(hù)紫外線的多功能棉織物,數(shù)十次水洗后仍能保持這些性能。該課題組[34]還報(bào)道了通過殼聚糖和聚苯胺制備多功能聚酯纖維,不僅具有高效的導(dǎo)電性,還具有極好的防水性,同時(shí)在紫外光下也表現(xiàn)出了光催化特性。
圖1 氧化石墨烯涂附纖維織物機(jī)理及實(shí)物圖[31]
圖2 棉織物表面沉積PG/CS涂層[33]
通過殼聚糖/石墨烯制備的涂層纖維與石墨烯結(jié)合牢固,導(dǎo)電性高,但殼聚糖只溶于某些稀酸和特定溶劑中,這一缺點(diǎn)限制了殼聚糖的使用。對殼聚糖進(jìn)行化學(xué)修飾可以改善這一問題,殼聚糖獲取成本低、來源廣泛,因此殼聚糖在石墨烯基復(fù)合涂層纖維領(lǐng)域具有廣闊的應(yīng)用前景。
牛血清蛋白(BSA)是一種兩性蛋白,其等電點(diǎn)為4.9。pH小于4.9時(shí),牛血清蛋白表面帶正電荷;pH大于4.9時(shí),牛血清蛋白表面帶負(fù)電荷。當(dāng)pH小于4.9時(shí),纖維表面附著帶正電荷的牛血清蛋白,與帶負(fù)電荷的氧化石墨烯在靜電作用下實(shí)現(xiàn)氧化石墨烯/牛血清蛋白復(fù)合涂層的自組裝。同時(shí)牛血清蛋白具有一定的黏性,能夠增強(qiáng)與氧化石墨烯的結(jié)合能力。牛血清蛋白是目前使用最多的方法之一。Yun 等[16]利用牛血清蛋白制備了石墨烯/牛血清蛋白涂層纖維,如圖3所示。纖維浸入牛血清蛋白溶液后烘干,再浸入氧化石墨烯溶液,通過靜電作用將氧化石墨烯吸附在纖維上,最后用碘化氫還原,制得電導(dǎo)率為1040 S/m的高導(dǎo)電性纖維。Wang等[35]將纖維浸入牛血清蛋白烘干后,涂附上銀和氧化石墨烯,用微波和檸檬酸還原2 h,獲得了1.6 Ω的導(dǎo)電纖維,并具有54.4 dB的電磁屏蔽功能。
牛血清蛋白性能穩(wěn)定,結(jié)合能力強(qiáng),不易脫落,但較高的成本限制了牛血清蛋白纖維在石墨烯基復(fù)合纖維中的應(yīng)用,難以工業(yè)化。
聚吡咯是一種雜環(huán)共軛型導(dǎo)電高分子,吡咯和石墨烯借助表面活性劑,分散后聚合,可以得到穩(wěn)定的導(dǎo)電聚合物。如圖4所示,Xu等[21]將棉織物浸入氧化石墨烯后熱還原,并加入吡咯(Py)聚合,獲得聚吡咯/還原氧化石墨烯(PPy/RGO)復(fù)合織物,其導(dǎo)電性為1.2 S/cm,并在熱還原過程中,氧化石墨烯與吡咯進(jìn)行原位聚合被還原。A. Berendjchi等[22]利用吡咯原位聚合對纖維進(jìn)行改性,在聚酯纖維表面涂附氧化石墨,制得5 Ω/sq的聚吡咯/石墨烯織物。
圖3 氧化石墨烯/牛血清蛋白沉積并還原于纖維表面示意圖[16]
圖4 還原氧化石墨烯/聚吡咯織物制備示意圖和實(shí)物圖[21]
將聚吡咯運(yùn)用于石墨烯基納米復(fù)合纖維有利于導(dǎo)電性能的提升,但該方法較為繁瑣,且吡咯不易保存,具有一定的毒性,后續(xù)的實(shí)際應(yīng)用易受到影響。
聚氨酯主鏈中含有氨基甲酸酯基的聚合物,其氨基與氧化石墨烯中含氧基團(tuán)容易形成氫鍵。聚氨酯作為分散劑[36],使石墨烯在溶液中穩(wěn)定分散,也作為粘結(jié)劑,增強(qiáng)石墨烯和纖維的結(jié)合力。
Kim等[37]設(shè)計(jì)了基于石墨烯/水性聚氨酯的導(dǎo)電織物,該課題組通過刀涂法將石墨烯/水性聚氨酯涂附在織物上,并在160 ℃下進(jìn)行退火處理,獲得了6.83 kΩ/sq的導(dǎo)電織物,其力學(xué)性能、抗拉強(qiáng)度都得到了提升。Hao[38]以水溶性聚氨酯(WPU)、石墨烯、復(fù)合油墨為原料,經(jīng)噴涂制備出一種具有夾層結(jié)構(gòu)的耐磨復(fù)合柔性織物。該織物具有良好的電熱性能,在10 V電壓下,30 s內(nèi)就達(dá)到75.4 ℃的溫度;此外,還具有優(yōu)異的耐磨性能,經(jīng)過2500個(gè)循環(huán)的耐磨性試驗(yàn),電導(dǎo)率僅降低了21.1%,遠(yuǎn)低于無夾層結(jié)構(gòu)的織物的87%。Liu[39]提出一種簡單的一步染色法,如圖5,以聚氨酯(PU)為粘結(jié)層,將石墨烯吸附并固定在聚酯織物表面,制備了一種結(jié)構(gòu)穩(wěn)定的導(dǎo)電織物,其方阻約2.0×10?5S/sq。
圖5 還原氧化石墨烯/聚氨酯涂層織物示意圖[39]
聚氨酯成本較低,來源廣泛,但聚氨酯不耐強(qiáng)極性溶劑和強(qiáng)酸堿介質(zhì),存在易發(fā)生降解溶脹等問題。
利用等離子體處理改性纖維:通過外加電流形成部分或全部電離的氣體,去除纖維表面的有機(jī)物污染(如油脂),并且對纖維進(jìn)行粗化與交聯(lián),增強(qiáng)結(jié)合力。
Molina等人[39]運(yùn)用等離子體處理聚酯(PET)纖維,使纖維表面帶上負(fù)電荷,增強(qiáng)與牛血清蛋白的結(jié)合能力。此外,等離子體處理過后,其表面粗糙度增加,更利于牛血清蛋白的吸附,通過連二亞硫酸鈉進(jìn)行還原,最后獲得9 Ω的高效導(dǎo)電纖維。Rani[12]使用等離子體對聚酯纖維進(jìn)行改性,分別設(shè)計(jì)了5、10、20、60 min的等離子體處理時(shí)間,并測定了它們的比表面積,得出經(jīng)10 min處理的纖維比表面積最大。通過牛血清蛋白和氧化石墨烯處理,利用肼蒸氣還原,得到479 Ω·m的導(dǎo)電纖維,比起不用等離子體處理的導(dǎo)電性提高了31%。
改性纖維的方法多種多樣,增強(qiáng)石墨烯或氧化石墨烯與纖維的結(jié)合能力是獲得合適涂層的關(guān)鍵。這些方法通過范德華力、氫鍵、π─π相互作用等增強(qiáng)石墨烯或氧化石墨烯與纖維的結(jié)合能力。然而,選用不同的方法制備石墨烯基纖維還需考慮成本、工藝、環(huán)保等多方面的影響。
石墨烯導(dǎo)電性優(yōu)越,并具有室溫量子霍爾效應(yīng),與碳纖維、碳納米管等材料相比,石墨烯可以突破碳材料原有的局限,成為一種新型電磁屏蔽材料。因此,石墨烯及其衍生物已被廣泛運(yùn)用于紡織領(lǐng)域,并獲得具有電磁屏蔽效果的多功能石墨烯基復(fù)合纖維織物。
Kanthasamy等[41]設(shè)計(jì)了MXene薄片-石墨烯-聚偏氟乙烯的復(fù)合涂層纖維,并獲得了3.1 Ω/sq的導(dǎo)電織物,其電磁屏蔽機(jī)理如圖6所示。入射電磁波大部分在MXene層發(fā)生反射,少部分在石墨烯層發(fā)生散射與多次內(nèi)反射,因此該結(jié)構(gòu)具有很好的電磁屏蔽性能。測試發(fā)現(xiàn),在X波段8~12 GHz范圍內(nèi),其電磁屏蔽效果可達(dá)到53.8 dB。Wang等[35]用牛血清蛋白涂附氧化石墨烯,烘干后浸入硝酸銀溶液,用檸檬酸鈉和微波(700 W)還原20 min,獲得了1.6 Ω的導(dǎo)電纖維,電磁屏蔽效果可達(dá)54.4 dB。該課題組Wang[17]在滌綸織物上進(jìn)行聚二烯丙基二甲基氯化銨(PDDA)和銀/還原氧化石墨烯(Ag/RGO)復(fù)合改性,獲得了0.173 Ω/sq的導(dǎo)電織物,在X波段8~ 12 GHz范圍內(nèi)測試,電磁屏蔽效果達(dá)52~57 dB。Tian等[42]將殼聚糖、聚苯乙烯磺酸鈉作為分散劑和粘合劑,將石墨烯涂附到纖維上,獲得石墨烯改性纖維,其電導(dǎo)率為1360 S/m,電磁屏蔽效果可達(dá)到30.04 dB。
圖6 MXene-石墨烯-聚偏氟乙烯復(fù)合涂層纖維的電磁屏蔽示意圖[41]
石墨烯及其衍生物在紫外線屏蔽織物中得到廣泛的運(yùn)用。石墨烯在100~281 nm紫外波段有吸收[43]。對于波長大于281 nm的紫外線,石墨烯同樣可以通過反射起阻抗作用,來屏蔽紫外線。紫外線防護(hù)系數(shù)(UPF)大于50,UVA波段的透過率小于5%,材料具有出色的紫外線阻隔效果。
B. Ouadil[14]利用氧化石墨烯和硝酸銀在聚酯纖維上通過浸漬-干燥法進(jìn)行改性,用連二亞硫酸鈉還原,獲得了0.06 MΩ/cm的導(dǎo)電纖維。該纖維在UVA的波段透過率小于0.8%,與未經(jīng)處理的純棉織物相比,紫外線透過率降低了73%。Pancliyarasan[44]通過水熱法在棉織物表面沉積還原氧化石墨烯,改性后織物的紫外線防護(hù)系數(shù)(UPF)為442.69(洗滌前)和422.32(洗滌后),而裸織物為7.83,說明還原氧化石墨烯織物的抗紫外線性不僅能得到顯著提高,還具有優(yōu)異的耐洗性能。Cai[45]將氧化石墨烯通過浸漬-干燥法涂附于棉織物表面,在氮?dú)獾谋Wo(hù)下進(jìn)行熱還原,獲得了UVA透過率小于2.49的紫外線防護(hù)織物。Hu[46]通過浸漬-烘干法制備了石墨烯/聚氨酯復(fù)合織物,如圖7所示,其紫外線防護(hù)系數(shù)接近500,約為普通棉布的60倍,經(jīng)10個(gè)周期的水洗仍能保持此性能。
圖7 石墨烯/聚氨酯涂層織物的紫外透射光譜和樣品織物的紫外線防護(hù)性能[46]
疏水材料是指材料表面與水的接觸角大于90°。當(dāng)接觸角大于150°,則被稱為超疏水材料,因其具有防水、抗油污等特殊性能受到人們的青睞。結(jié)構(gòu)規(guī)整的石墨烯表現(xiàn)為疏水性。氧化石墨烯表面含有較多的含氧基團(tuán),表現(xiàn)為親水性,其邊緣含氧基團(tuán)更為密集,親水性更為明顯。但還原氧化石墨烯因?yàn)楹豕倌軋F(tuán)被去除,從而表現(xiàn)疏水的性質(zhì)。
Attia等[47]以石墨烯、磷酸銨和N-3-三甲氧基硅基丙基乙二胺為原料,通過工業(yè)粘結(jié)劑,制備了一種新型涂層,并將二氧化鈦納米粒子進(jìn)一步分散在涂層中,不僅提升其力學(xué)性能和抗拉伸強(qiáng)度,還達(dá)到145°的水接觸角,提高了材料的疏水性能。Wu等[48]使用氧化石墨烯對粘膠織物進(jìn)行浸漬-干燥循環(huán)處理,最后用水合肼進(jìn)行還原,經(jīng)過12個(gè)周期處理的粘膠纖維織物的水接觸角為125°,原纖維織物的水接觸角為18°,說明織物的疏水性能得到了提高。A. Berendjchi等[22]利用吡咯原位聚合對纖維進(jìn)行改性,并制得具有高導(dǎo)電性和高疏水性的多功能織物,如圖8所示。獲得的還原氧化石墨烯涂層纖維樣品與水的接觸角為127°,具有優(yōu)異的疏水性。
圖8 還原氧化石墨烯涂層織物上的水滴靜態(tài)接觸角[22]
石墨烯所具有的高導(dǎo)電性和高比表面積等性質(zhì),使得它很適合在織物領(lǐng)域被制作成傳感器。第16屆IEEE傳感器會(huì)議上,Golparvar[49]報(bào)告了一種石墨烯基可穿戴導(dǎo)電織物傳感器,解決了傳統(tǒng)“濕”電極的局限性,并與銀/氯化銀電極比較,記錄的信號與達(dá)到的時(shí)間相關(guān)性高達(dá)87%,這一出色的性能證明了石墨烯紡織品在傳感和可穿戴設(shè)備中的潛力。Jin[50]利用還原氧化石墨烯涂附在尼龍纖維上,并與銀導(dǎo)電線縫合,放入滌綸織物中,創(chuàng)造了一種新的負(fù)溫度系數(shù)(NTC)材料,用于監(jiān)測皮膚的溫度。在一定范圍的彎曲和拉伸程度中,其表現(xiàn)出機(jī)械性和電穩(wěn)定性。He[50]報(bào)道了一種基于石墨烯浸漬和銀磁控濺射的高導(dǎo)電涂層。該課題組通過浸漬法,使用還原氧化石墨烯對棉布進(jìn)行修飾,用磁控濺射系統(tǒng)對其鍍銀薄膜,制作了一種新的應(yīng)變傳感器,該傳感器具有靈敏度高、應(yīng)變范圍大、響應(yīng)快、穩(wěn)定性好等優(yōu)點(diǎn)。它可以實(shí)時(shí)監(jiān)測人類運(yùn)動(dòng),如彎曲和手指旋轉(zhuǎn),具有很好的應(yīng)用潛力。N. Karim[52]利用浸漬-干燥法制備出還原氧化石墨烯/聚苯乙烯磺酸鈉織物,并設(shè)計(jì)成一種可伸縮的傳感器,如圖9所示。在拉伸過程中,電阻相對變化值保持恒定,可用于檢測手腕等關(guān)節(jié)運(yùn)動(dòng)。
圖9 還原氧化石墨烯涂層織物制備傳感器[52]
隨著可穿戴電子器件的快速發(fā)展,人們對柔性儲(chǔ)能器件的需求也逐步增加。傳統(tǒng)電容器因其剛性外殼和液態(tài)電解質(zhì)的性質(zhì),難以滿足柔性工作環(huán)境下的儲(chǔ)能需求。因此,具有快速充放電倍率、良好柔韌性和長循環(huán)壽命的超級電容器成為最近的研究熱點(diǎn)。石墨烯由于其超高的比表面積、高的導(dǎo)電性、良好的力學(xué)強(qiáng)度,能夠顯著提高電容器的性能,減少其內(nèi)部電阻,提升充放電速率,因此在制備柔性超級電容器方面有巨大的應(yīng)用潛力。
Xu[53]在還原氧化石墨烯/碳納米管的納米復(fù)合膜中加入導(dǎo)電聚合物聚-3,4-乙二氧基噻吩(PEDOT),在柔性無紡布基體上成功制備了一種新型復(fù)合電容。該電容在電流密度0.1 A/g時(shí),比電容高達(dá)164 F/g。此外復(fù)合電容還具有良好的穩(wěn)定性,彎曲1000次后,電容保持率超過93%。Wang[54]在聚酯織物上通過激光涂附氧化石墨烯涂層,利用戊二醛將氧化石墨烯層和聚乙二醇-凝膠電解質(zhì)進(jìn)行交聯(lián),提高其耐洗牢固度和柔韌性。在20 mV/s環(huán)境下,具有756 mμF/cm2的電容;經(jīng)過1000次循環(huán)后,仍能有98.3%電容保持率。Jin[55]采用浸漬-干燥法和電泳沉積法,在滌綸織物上成功構(gòu)建了碳納米管和石墨烯的三維導(dǎo)電網(wǎng)絡(luò),制備了一種可彎曲超級電容,當(dāng)電流密度為1.5 mA/cm2時(shí),復(fù)合電極的最大面積電容為791 mF/cm2,3000次充放電循環(huán)后,復(fù)合電極的電容保持率仍超過76%。在機(jī)械彎曲和拉伸條件下,復(fù)合電極也表現(xiàn)出穩(wěn)定的電化學(xué)性能。Zhu[56]設(shè)計(jì)了一種特殊的結(jié)構(gòu)電極,通過還原氧化石墨烯/MnO2涂層碳纖維,還原氧化石墨烯/MnO2電極在2 mV/s表現(xiàn)出了超高的區(qū)域電容(8132 mF/cm2),在120 mA/cm2環(huán)境下進(jìn)行30 000次充放電循環(huán),電容保持率可達(dá)95%,經(jīng)2000次、4000次和6000次不同方向折疊后,仍能保持90%、85%和77%的電容。LI[57]提出一種基于石墨烯和MnO2沉積無紡布柔性超級電容的方法,如圖10所示。采用毛細(xì)管輔助組裝法和原位化學(xué)生長法在無紡布上沉積石墨烯與MnO2(GMNF),獲得138.8 mF/cm2的石墨烯 MnO2柔性超級電容(GMNF-SC),其具有良好的導(dǎo)電性、柔韌性,在180°彎折下循環(huán)充、放電1000次,電容保持率仍可達(dá)87.6%。目前的研究報(bào)道表明,石墨烯涂層纖維在柔性超級電容器上的應(yīng)用,還有很大的發(fā)展空間。
圖10 石墨烯/二氧化錳涂層織物(GMNF)的制備方法和石墨烯/二氧化錳柔性超級電容(GMNF-SC)的制備示意圖[57]
石墨烯作為一種革命性材料,由于極大的比表面積、高導(dǎo)電性等性能,制得的石墨烯基復(fù)合涂層纖維在電磁屏蔽、紫外線防護(hù)、傳感器、超級電容等諸多領(lǐng)域有很好的應(yīng)用前景。然而,在實(shí)際操作中,仍有著許多的問題有待解決:1)涂附過程中如何使石墨烯穩(wěn)定均勻涂覆問題;2)石墨烯基復(fù)合涂層與基底的牢固結(jié)合問題;3)纖維表面改性方法(如對纖維表面使用牛血清蛋白、等離子體、聚吡咯等方法)的工業(yè)化操作、成本等問題。當(dāng)然,石墨烯改性纖維,除了利用石墨烯本身具有的特性,還可以通過摻雜等手段賦予其更多功能,實(shí)現(xiàn)纖維多功能化,這也是十分重要的研究方向。
[1] NOVSELOV K S. Electric field effect in atomically thin carbon films[J]. Science, 2004, 306(5696): 666-669.
[2] KARIMI K, JABARI E, TOYSERKANI E, et al. Highly conductive graphene paper for flexible electronics applications[J]. Journal of materials science materials in electronics, 2018, 29(3): 2537-2549.
[3] JIN L, ZHAO X, XU J, et al. The synergistic effect of a graphene nanoplate/Fe3O4@BaTiO3hybrid and MWCNTs on enhancing broadband electromagnetic interference shi-elding performance[J]. RSC advances, 2018, 8(4): 2065- 2071.
[4] MCCAFFREY DEBRA L, NGUYEN SON C, COX STEPHEN J, et al. Mechanism of ion adsorption to aqueous interfaces: Graphene/water vs. air/water[J]. Proceedings of the national academy of sciences of the united states of America, 2017, 114(51): 13369-13373.
[5] HUANG G, YANG J, GAO J, et al. Thin films of intumescent flame retardant-polyacrylamide and exfoliated graphene oxide fabricated via layer-by-layer assembly for improving flame retardant properties of cotton fabric[J]. Industrial & engineering chemistry research, 2016, 51 (38): 12355-12366.
[6] NOVOSELOV K S, FAL'KO V I, COLOMBO L, et al. A roadmap for graphene[J]. Nature, 2012, 490(7419): 192- 200.
[7] GREEN A A, HERSAM M C. Emerging methods for producing monodisperse graphene dispersions[J]. Journal of physical chemistry letters, 2016, 1(2): 544-549.
[8] JUNGWOO T S, ALEXANDER A G, ALEXANDER L, et al. High-concentration aqueous dispersions of graphene using nonionic, biocompatible block copolymers[J]. Jour-nal of physical chemistry letters, 2016, 2(9): 1004-1008.
[9] GUEX L G, SACCHI B, PEUVOT K F, et al. Experimental review: chemical reduction of graphene oxideto reduced graphene oxide by aqueous chemistry[J]. Nanoscale, 2017, 9(27): 9562-9571.
[10] NEVELEE H, GLASPER M J, LI X, et al. Preparation of fabric strain sensor based on graphene for human motion monitoring[J]. Journal of materials science, 2018, 53(12): 1-8.
[11] PAN N, LIU Y, REN X, et al. Fabrication of cotton fabrics through in-situ reduction of polymeric N-halamine modified graphene oxide with enhanced ultraviolet-blocking, self-cleaning, and highly efficient, and monitorable antibacterial properties[J]. Colloids and surfaces A: Physicochemical and engineering aspects, 2018, 555: 765-771.
[12] RANI K V, SARMA B, SARMA A. Plasma treatment on cotton fabrics to enhance the adhesion of reduced graphene oxide for electro-conductive properties[J]. Diamond and related materials, 2018, 84: 77-85.
[13] ZHAO K, WANG Y, WANG W, et al. Moisture absorption, perspiration and thermal conductive polyester fabric prepared by thiolene click chemistry with reduced graphene oxide finishing agent[J]. Journal of materials science, 2018, 53(20): 14262-14273.
[14] OUADIL B, CHERKAOUI O, SAFI M, et al. Surface modification of knit polyester fabric for mechanical, electrical and UV protection properties by coating with graphene oxide, graphene and graphene/silver nanocomposites[J]. Applied surface science, 2017, 414: 292-302.
[15] KARIM N, AFROJ S, TAN S, et al. Scalable production of graphene-based wearable E-textiles[J]. Acsnano, 2017, 11(12): 12266-12275.
[16] YUN Y J, HONG W G, KIM W J, et al. A novel method for applying reduced graphene oxide directly to electronic textiles from yarns to fabrics[J]. Advanced materials, 2013, 25(40): 5701-5705.
[17] WANG C, GUO R, LAN J, et al. Preparation of multi- functional fabric via silver/reduced graphene oxide coating with poly (diallyldimethylammonium chloride) modification[J]. Journal of materials science materials in electronics, 2018, 29(10): 8010-8019.
[18] YIN F, YANG J, PENG H, et al. Flexible and highly sensitive artificial electronic skin based on graphene/ polyamide interlocking fabric[J]. Journal of materials chemistry C, 2018, 6(25): 6840-6846.
[19] MIRJALILI M. Preparation of electroconductive, magnetic, antibacterial, and ultraviolet-blocking cotton fabric using reduced graphene oxide nanosheets and magnetite nanoparticles[J]. Fibers & polymers, 2016, 17(10): 1579- 1588.
[20] BABAAHMADI V, MONTAZER M, GAO W. Surface modification of PET fabric through in-situ, reduction and cross-linking of graphene oxide: Towards developing durable conductive fabric coatings[J]. Colloids & surfaces a physicochemical & engineering aspects, 2018, 545: 16- 25.
[21] XU J, WANG D, YUAN Y, et al. Polypyrrole/reduced graphene oxide coated fabric electrodes for supercapacitor application[J]. Organic electronics, 2015, 24: 153-159.
[22] BERENDJCHI A, KHAJAVI R, YOUSEFI A, et al. Improved continuity of reduced graphene oxide on polyester fabric by use of polypyrrole to achieve a highly electro- conductive and flexible substrate[J]. Applied surface science, 2016, 363: 264-272.
[23] LIU L, YU Y, YAN C, et al. Wearable energy-dense and power-dense supercapacitor yarns enabled by scalable graphene-metallic textile composite electrodes[J]. Nature communications, 2015, 6: 7260.
[24] PARK Y, PARK M, LEE J. Reduced graphene oxide- based artificial synapse yarns for wearable textile device applications[J]. Advanced functional materials, 2018, 28(42): 1804123.
[25] TANG X, TIAN M, QU L, et al. Functionalization of cotton fabric with graphene oxide nanosheet and polyaniline for conductive and UV blocking properties[J]. Synthetic metals, 2015, 202: 82-88.
[26] JEON H, JEONG J, HONG S B, et al. Facile and fast microwave-assisted fabrication of activated and porous carbon cloth composites with graphene and MnO2, for flexible asymmetric supercapacitors[J]. Electrochimica acta, 2018, 280: 9-16.
[27] SUN H, FU C, GAO Y, et al. Electrical property of macroscopic graphene composite fibers prepared by chemical vapor deposition[J]. Nanotechnology, 2018, 29(30): 305601.
[28] NEVES A I S, RODRIGUES D P, SANCTIS A, et al. Towards conductive textiles: Coating polymeric fibers with graphene[J]. Scientific reports, 2017, 7(1): 4250.
[29] LIANG B, FANG L, HU Y, et al. Fabrication and application of flexible graphene silk composite film electrodes decorated with spiky Pt nanospheres[J]. Nanoscale, 2014, 6(8): 4264-4274.
[30] NEVES A I S, HONG H, CHEN S, et al. Study on the friction reducing effect of graphene coating prepared by electrophoretic deposition[J]. Procedia cirp, 2018, 71: 335-340.
[31] SAMAD Y A, LI Y, ALHASSAN S M, et al. Non- destroyable graphene cladding on a range of textile and other fibers and fiber mats[J]. RSC advances, 2014, 4(33): 16935-16938.
[32] PAN H, WANG W, PAN Y, et al. Formation of self- extinguishing flame retardant bio-based coating on cotton fabrics via layer-by-layer assembly of chitin derivatives[J]. Carbohydrate polymers, 2015, 115: 516-524.
[33] TIAN M, HU X, QU L, et al. Versatile and ductile cotton fabric achieved via layer-by-layer self-assembly by consecutive adsorption of graphene doped PEDOT: PSS and chitosan[J]. Carbon, 2016, 96: 1166-1174.
[34] TANG X, TIAN M, QU L, et al. A facile fabrication of multifunctional knit polyester fabric based on chitosan and polyaniline polymer nanocomposite[J]. Applied surface science, 2014, 317: 505-510.
[35] WANG C, GUO R, LIN S, et al. A highly electro- conductive and flexible fabric functionalized with bovine serum albumin for a wearable electronic device[J]. Journal of materials science materials in electronics, 2018, 29(17): 14927-14934.
[36] MOLINA J. Graphene-based fabrics and their applications: a review[J]. RSC advances, 2016, 6(72): 68261- 68291.
[37] KIM H, LEE S. Characteristics of electrical heating elements coated with graphene nanocomposite on polyester fabric: effect of different graphene contents and annealing temperatures[J]. Fibers & polymers, 2018, 19(5): 965-976.
[38] HAO Y, TIAN M, ZHAO H, et al. High efficiency electrothermal graphene/tourmaline composite fabric joule heater with durable abrasion resistance via a spray coating route[J]. Industrial & engineering chemistry research, 2018, 57(40): 13437-13448.
[39] LIU X, QIN Z, DOU Z, et al. Fabricating conductive poly(ethylene terephthalate) nonwoven fabrics using an aqueous dispersion of reduced graphene oxide as a sheet dyestuff[J]. RSC advances, 2014, 4(25): 23869-23875.
[40] MOLINA J, FERNáNDEZ J, FERNANDES M, et al. Plasma treatment of polyester fabrics to increase the adhesion of reduced graphene oxide[J]. Synthetic metals, 2015, 202(9): 110-122.
[41] RAAGULAN K, BRAVEENTH R, JANG H, et al. Electromagnetic shielding by MXENE-Graphene-PVDF com-posite with hydrophobic, lightweight and flexible graphene coated fabric[J]. Materials, 2018, 11(10): 1803.
[42] TIAN M, DU M, QU L, et al. Electromagnetic interference shielding cotton fabrics with high electrical conductivity and electrical heating behavior via layer-by-layer self-assembly route[J]. RSC advances, 2017, 7(68): 42641- 42652.
[43] QU L, TIAN M, HU X, et al. Functionalization of cotton fabric at low graphene nanoplate content for ultrastrong ultraviolet blocking[J]. Carbon, 2014, 80: 565-574.
[44] PANDIYARASAN V, ARCHANA J, PAVITHRA A, et al. Hydrothermal growth of reduced graphene oxide on cotton fabric for enhanced ultraviolet protection applications[J]. Materials letters, 2017, 188: 123-126.
[45] CAI G, XU Z, YANG M, et al. Functionalization of cotton fabrics through thermal reduction of graphene oxide[J]. Applied surface science, 2017, 393: 441-448.
[46] HU X, TIAN M, QU L, et al. Multifunctional cotton fabrics with graphene/polyurethane coatings with far-infrared emission, electrical conductivity, and ultraviolet-blocking properties[J]. Carbon, 2015, 95: 625-633.
[47] ATTIA N F, MOUSA M. Synthesis of smart coating for furniture textile and their flammability and hydrophobic properties[J]. Progress in organic coatings, 2017, 110: 204-209.
[48] WU W, ZHANG H, MA H, et al. Functional finishing of viscose knitted fabrics via graphene coating[J]. Journal of engineered fibers and fabrics, 2017, 12(3): 1-6.
[49] GOLPARVAR A J, YAPICI M K. Electrooculography by wearable graphene textiles[J]. IEEE sensors journal, 2018, 18(21): 8971-8978.
[50] JIN Y, BOON E P, LE L T, et al. Fabric-infused array of reduced graphene oxide sensors for mapping of skin temperatures[J]. Sensors & actuators A physical, 2018, 280: 92-98.
[51] HE S, XIN B, CHEN Z, et al. Flexible and highly conductive Ag/G-coated cotton fabric based on graphene dipping and silver magnetron sputtering[J]. Cellulose, 2018, 25(1530-1534): 1-11.
[52] KARIM N, AFROJ S, TAN S, et al. Scalable production of graphene-based wearable e-textiles[J]. ACS nano, 2017, 11(12): 12266-12275.
[53] XU L, XU J, YANG Y, et al. A flexible fabric electrode with hierarchical carbon-polymer composite for functional supercapacitors[J]. Journal of materials science materials in electronics, 2018, 29(3): 2322-2330.
[54] WANG G, BABAAHMADI V, HE N, et al. Wearable supercapacitors on polyethylene terephthalate fabrics with good wash fastness and high flexibility[J]. Journal of power sources, 2017, 367: 34-41.
[55] JIN L N, SHAO F, JIN C, et al. High-performance textile supercapacitor electrode materials enhanced with three- dimensional carbon nanotubes/graphene conductive network and in situ polymerized polyaniline[J]. Electrochimica acta, 2017, 249: 387-394.
[56] ZHU J, ZHAO S, WU X, et al. Wrapping RGO/MoO2carbon textile as supercapacitor electrode with enhanced flexibility and areal capacitance[J]. Electrochimica acta, 2018, 282: 784-791.
[57] LI Z, TIAN M, SUN X, et al. Flexible all-solid planar fibrous cellulose nonwoven fabric-based supercapacitor via capillarity-assisted graphene/MnO2assembly[J]. Journal of alloys and compounds, 2019, 782: 986-994.
Preparation and Application of Graphene Nanocomposite Coating on Fabrics
1,2,1,1
(1.School of Materials Science and Engineering, Huaqiao University, Xiamen 361021, China; 2.Fujian Key Laboratory of Sports Shoe Fabrics, Fujian Huafeng New Materials Co., Ltd, Putian 351144, China)
Graphene attracts researchers' attention due to unique properties of excellent electrical conductivity, huge specific surface area, high Young's modulus, etc. The current research aims to apply the Graphene into the surface modification of fibers to realize the electrical conductivity, UV protection, electromagnetic shielding, and etc. of fabrics. Therefore, graphene nanocomposite coated fibers have great application prospects in medical devices, electronic devices and sensor. Graphene nanocomposite coating was introduced from three aspects including mechanism, preparation method and properties and application and the mechanism of graphene nanocomposite coating was described. The preparation methods of graphene nanocomposite coating were summarized, of which the immersion method had advantages of simple operation, low pollution, low energy consumption, and good repeatability. Through methods such as chitosan, bovine serum albumin and polyurethane, the surface of fibers could be modified and the binding force between the graphene nanocomposite coating and the substrate could be enhanced to improve the comprehensive performance of graphene nanocomposite coating. The application and research status of graphene nanocomposite coated fibers and fabrics in electromagnetic shielding materials, hydrophobic materials, flexible electrodes, ultracapacitors, sensors and other fields are summarized, and the development is also prospected.
graphene; coating; fiber; flexible electrode; conductive fabric; sensor
2018-11-27;
2019-02-16
FAN Peng (1995—), Male, Master, Research focus: chemistry and physics of polymers.
陳國華(1964—),男,博士,教授,主要研究方向?yàn)槭┑闹苽浼捌渚酆衔锘鶑?fù)合材料研究。郵箱:hdcgh@foxmail.com
TG174.43
A
1001-3660(2019)06-0056-10
10.16490/j.cnki.issn.1001-3660.2019.06.005
2018-11-27;
2019-02-16
國家自然科學(xué)基金資助項(xiàng)目(51373059);福建省科技計(jì)劃項(xiàng)目(2018H6012,2018H009,2017H2001);福建省運(yùn)動(dòng)鞋面料重點(diǎn)實(shí)驗(yàn)室(福建華峰新材料有限公司)開放基金項(xiàng)目資助
Supported by the National Natural Science Foundation of China (51373059), Fujian Provincial Science and Technology Planning Project (2018H6012, 2018H009, 2017H2001), Funding of Fujian Key Laboratory of Sports Shoe and Fabric Open Fund Project (Fujian Huafeng New Material Co., Ltd.)
范鵬(1995—),男,碩士研究生,主要研究方向?yàn)楦叻肿踊瘜W(xué)與物理。
CHEN Guo-hua (1964—), Male, Ph. D., Professor, Research focus: preparation of graphene and study on polymer matrix composites. E-mail: hdcgh@foxmail.com