Photopolymerization of ionic liquids in flexible microporous aramids for ion conductive solid polyelectrolytes

Jou nal o Pho ochemis y & Pho obiology, A: Chemis y 422 (2022) 113571 A ailable online 4 Oc obe 2021 1010-6030/© 2021 The Au ho (s). Published by Else ie B.V. This is an open access a icle unde he CC BY license (h p://c ea i ecommons.o g/licenses/by/4.0/). Pho opolyme iza ion o ionic liquids in lexible mic opo ous a amids o ion conduc i e solid polyelec oly es M. T igo L´ opez a , J.A. Regle o Ruiz a , J.L. Pablos b , * , D.E. Ciu duc c , T. Co ales b , * , F.C. Ga cía a , J.M. Ga cía a a Depa amen o de Química, Facul ad de Ciencias, Uni e sidad de Bu gos, Plaza de Misael Ba˜ nuelos s/n, 09001 Bu gos, Spain b G upo de Fo oquímica de Políme os, Ins i u o de Ciencia y Tecnología de Políme os, Consejo Supe io de In es igaciones Cien í icas, ICTP-CSIC, Juan de la Cie a 3, 28006 Mad id, Spain c Elec ochemical P ocesses Uni , IMDEA Ene gy, A . Ram´ on de La Sag a, 3, 28935 M´ os oles, Spain ARTICLE INFO Keywo ds: Mic opo ous a amid Flexible solid elec oly es Pho opolyme izable ionic liquids ABSTRACT This wo k p esen s he p epa a ion o no el solid polyme elec oly es based on lexible mic opo ous a amids illed wi h pho opolyme ized ionic liquids and li hium sal . The ma e ials combined a high ionic conduc i i y wi h he mechanical and he mal cha ac e is ics o he a amids, including also good lexibili y and handleabili y. Fi s , a simple cas ing p ocess was ollowed o ob ain mic opo ous a amids wi h an in e connec ed channel mo phology. In a second s ep, his channel s uc u e was illed wi h a solu ion o non-comme cial pho o- polyme izable ionic liquid, comme cial ionic liquids and he li hium sal , ollowed by UV i adia ion o ob ain he conduc ing a amids. Ionic conduc i i y o he ma e ials was s udied a 25 ◦C, and also in he empe a u e ange be ween −50 o 90 ◦C, oge he wi h SEM analyses o he illed po ous s uc u e and he mal p ope ies, o ully cha ac e ize he pho opolyme iza ion p ocess o he ionic liquids inside he po ous s uc u e. The ma e ials showed high ionic conduc i i y alues oge he wi h excellen he mal and mechanical p ope ies, indica ing hei iabili y as lexible and he mally s able solid elec oly es. 1. In oduc ion Solid-s a e polyme elec oly es o applica ion in li hium ba e ies has become one o he mos impo an esea ch opics in he las decade, which is d i en by he need o enhance hei sa e y oge he wi h he de elopmen o lexible elec oly es wi h good elec ochemical s abili y and high conduc i i y alues [1,2]. Mainly, he ab ica ion o solid gel polyme elec oly es uses polye hylene oxide (PEO) o dissol e li hium sal s [3], and ollowing his esea ch line, di e en app oaches ha e been ca ied ou o imp o e he abili y o anspo li hium ions, such as he addi ion o ce amic ille s [4] o ca bon nano ubes [5]. One o he mos p omising esea ches o imp o e he pe o mance o li hium me al polyme ba e ies is he addi ion o ionic liquids (ILs) [6,7]. In his sense, ILs can be employed as plas icize s, lowe ing he glass ansi ion em- pe a u e o PEO imp o ing he ionic mobili y and, he e o e, hei ionic conduc i i y [8]. Fo his eason, e na y sys ems (polyme -li hium sal -IL) ha e been in es iga ed, (in which PEO ac s as hos polyme ), in e ms o he di e en in e ac ion mechanisms be ween all he componen s [9,10]. Among all he ILs in es iga ed, imidazolium-based ILs p esen good miscibili y wi h PEO, and ionic conduc i i y can be con olled wi h he quan i y o IL [11]. Howe e , he e is a majo disad an age in he use o PEO, conce ning i s insu icien ionic conduc i i y de i ed om he c ys allini y o he e hylene oxide sequences, which can es ain he ionic ansi ion due o he s i s uc u e, especially a low empe a u e [12]. Then, di e en al e na i es a e cu en ly being explo ed, employing o he amo phous polyme s such as poly(me hyl me hac y- la e) o poly(me hyl ac yla e) [13]. Cu en ly, he main esea ch line o ob ain highly e icien li hium ba e ies is ocused in he design o solid elec oly es wi h elec o- chemical cha ac e is ics compa able o hose o liquid ones, he so called solid-gel elec oly es. These ma e ials mus combine high ionic di u- si i y (and hence high ionic conduc i i y) and dimensional s abili y. In his ield, one o he bes candida es a e polyme ionic liquids (PILs), in which ILs a e chemically linked h ough di e en polyme iza ion mechanisms [14]. Al hough di e en ILs ha e been employed o enhance ionic conduc i i y [7], imidazolium-based ILs ha e eme ged as he ideal candida es o ob ain highly e icien ion gel elec oly es * Co esponding au ho s. E-mail add esses: [email p o ec ed] (J.L. Pablos), [email p o ec ed] (T. Co ales). Con en s lis s a ailable a ScienceDi ec Jou nal o Pho ochemis y & Pho obiology, A: Chemis y jou nal homepage: www.else ie .com/loca e/jpho ochem h ps://doi.o g/10.1016/j.jpho ochem.2021.113571 Recei ed 26 May 2021; Recei ed in e ised o m 22 Sep embe 2021; Accep ed 25 Sep embe 2021 Jou nal o Pho ochemis y & Pho obiology, A: Chemis y 422 (2022) 113571 2 [15,16], ela ed o hei high he mal s abili y which is pa ly assigned o he a oma ic na u e o he ing as well as in e molecula hyd ogen- bonding [17]. Mo eo e , imidazolium-based ionic liquids show high ionic conduc i i ies eaching alues o 10 −2 S/cm in addi ion o a su - icien ly high alue o elec ochemical window o hese compounds o abou 4 V [18], ha allows o a b oad applica ion ange o solid polyme elec oly es de ice ab ica ion [19]. The li e a u e ega ding PILs is ex ensi e [20]. Fo example, Washi o e al. [21] employed imidaziolium-based ionic liquids polyme s wi h di e en hyd oca bon chain leng hs, and Ahia a e al. [22] used PEO copolyme s o p epa e lexible polyme ilms o be used as solid elec- oly es, bu he ob ained ma e ials p esen ed a low glass ansi ion empe a u e, hus limi ing d as ically hei applicabili y. Appe ecchi e al., epo ed he elec ochemical p ope ies o e na y polyme elec- oly es o li hium ba e ies based on a no el poly(dia- llyldime hylammonium) bis( i luo ome hanesul onyl)imide, inco po a ing py olidinium-based polyme ic ionic liquids [23]. Also, ou g oup has de eloped ion gel elec oly es using pho opolyme izable ILs, such as 1-(2-me hac yloyloxy)e hyl-3-bu ylimidazolium bis( i luo ome hane sul onyl) imide (IMMA), and a mix u e o 1-e hyl-3-me hylimidazolium bis( luo osul onyl)imide (EMIFSI) o 1-bu yl-1-me hylpy olidinium bis ( luo osul onyl)imide (BMPFSI) and bis( i luo ome hane)sul onimide li hium sal (LiTFSI), p esen ing high ionic conduc i i y a RT (≈10 -2 S/ cm) and good he mal s abili y up o 200 ◦C [24]. Bea ing all hese ideas in mind, i is clea ha he e is a need o ob ain new ma e ials o be used as solid-gel elec oly es, combining di e en cha ac e is ics, such as high he mal esis ance, high ionic conduc i i y in a wide ange o empe a u es, lexibili y and mechanical s abili y. In pa allel, ou g oup has de eloped an easy me hod o ob ain mic opo ous a amids, based in he use o ILs o gene a e con olled po osi y. These ma e ials p esen excep ional mechanical and he mal s abili y (up o 350 ◦C), combined wi h low densi y (a ound 0.2 g/cm 3 , a educ ion o 6 imes espec o dense a amid) and excellen lexibili y and handleabili y [25]. These ma e ials can be employed as a polyme ic sca old in which polyme izable ionic liquids and li hium sal s can be in oduced, aking ad an age o he su ace po osi y o he a amids. In a second phase, polyme iza ion can ake place inside he po ous s uc u e, ob aining a solid gel elec oly e wi h high ionic conduc i i y and excellen mechanical and he mal p ope ies. The li e a u e al eady shows se e al wo ks in which po ous polyme s a e employed as solid gel elec oly es in li hium ion ba e ies [26], mainly based in po ous poly ( inylidene luo ide) (PVDF) [27,28], li hium poly[4-s y enesul onyl (phenylsul onyl)imide] [29] o poly(diallyldime hylammonium) bis ( i luo ome hanesul onyl)imide [30]. Howe e , he basis o ou app oach is comple ely di e en , mic opo ous a amids a e employed as solid polyme ic suppo s in which he pho opolyme iza ion o he IL is ca ied ou inside he po ous s uc u e p e iously p epa ed. In his way, ion conduc i i y is also enhanced h ough physical me hods, due o he speci ic po ous mo phology, in which hei in e connec ed mic o- channels would allow g ea ion mobili y be ween he elec odes. Then, he main objec i e o his wo k is o de elop new solid-gel polyme ic ma e ials based on pho opolyme isa ion o ILs inside mic o- po ous a amids, ha ing op imum p ope ies o be used as highly ionic conduc i e solid elec oly e. In ou app oach, he po ous a amid ac s as a polyme ic suppo and he ionic conduc i i y is ela ed exclusi ely o he sys em li hium sal s/ILs, which is in oduced illing he in e - connec ed po ous s uc u e o he a amid, and pho opolyme ized a - e wa ds. This new ma e ial combines he excellen he mal and mechanical s abili y, good handleabili y and lexibili y o he a amids, oge he wi h he excellen ionic conduc i i y p o ided by he ionic liquid, opening an in e es ing esea ch ield in which hese ma e ials could be used as solid polyme ic elec oly es in Li-ion ba e ies. 2. Expe imen al 2.1. Ma e ials All ma e ials, eac an s and sol en s we e used as ecei ed. Com- me cial poly(m-phenylene isoph halamide) (MPIA), a amid ibe Twa on® (nonwo en egula s aple ibe o a e age leng h 6.4 mm, 4.94 cN/d ex, ρ ≈1.38 g/cm 3 and T m >400 ◦C), was used. Two di e en ionic liquids we e employed: 1-e hyl-3-me hylimidazolium b omide (IL) (≥97 %), pu chased om Sigma-Ald ich, and 1-e hyl-3-me hylimidazo- lium bis( i luo ome hane)sul onamide (EMIM TFSI, 99.5 %) pu chased om Sol ionic. E hyleneglycol dime hac yla e (EGDM, 98 %), c oss- linke bis( i luo ome hane) sul onamide li hium sal (LiTFSI, 99.95 %), and I gacu e 659 (pho oin ia o , 98 %) we e pu chased om Sigma- Ald ich. 2-b omoe hanol (95 %), ie hylamine (>99 %), me hac yloyl chlo- ide (97 %), 1-bu ylimidazole (98 %), N,N-dime hylace amide (DMAc, >99 %) and dichlo ome hane (DCM, 99.99 %) we e employed, all o hem pu chased om Sigma-Ald ich. Hyd oquinone (99.5 %) was pu - chased om Pan eac, and inally milliQ wa e and hexane (99.8 %), pu chased om Scha lau, we e used. 2.2. Cha ac e iza ion and p ocedu es SEM mic og aphs we e aken using a Scanning Elec onic Mic o- scope JEOL JSM-6460LV. A amid ilms we e ozen in liquid ni ogen, ac u ed and gold coa ed in acuum o assu e he elec ical conduc- i i y o he ma e ials. Fo illed ma e ials, SEM pic u es we e aken wi hou gold coa ing. I has been obse ed, ha he condi ions o high acuum o SEM analysis p ocedu e did no a ec o he liquid o poly- me ized phase o a amid discs. Po ous s uc u e was cha ac e ized by de e mining he a e age bubble adius R and a e age cell densi y om SEM images was measu ed using ImageJ® so wa e and consis ed o coun ing he numbe o bubbles in each image n i and i s adius R i [31]. The a e age adius was calcula ed using Eq. (1), whe e N ep esen s he bubble coun . R=∑N i=1niRi ∑N i=1ni (1) Th ee di e en SEM images we e analyzed om each ma e ial, and he da a was a e aged. The es ima ion o he cell densi y N c was calcula ed using he Kuma ’s app oxima ion, as shown in Eq. (2), whe e n is he numbe o cells in he image and A is he a ea o he image. The desc ip ion o he calcula ion me hod can be ound in ou p e ious wo k [32] Nc=(n A)3/2(2) Densi y was de e mined om he dimensions and weigh o he samples, de e mining he hickness by di ec ly using a digi al mic ome e . The he mog a ime ic analysis da a we e eco ded on a TA Ins u- men Q50 TGA analyze . TGA es s we e pe o med unde O 2 (syn he ic ai ) a mosphe e using he nex p ocedu e: i s , samples we e hea ed om RT o 100 ◦C a 10 ◦C/min, and hen kep du ing 10 min o elim- ina e he mois u e con en . Then, samples we e hea ed up o 800 ◦C a 10 ◦C/min. Di e en ial Scanning Calo ime y (DSC) es s we e pe o med in a DSC Q200 TA Ins umen s o e alua e he he mal ansi ions o he ma e ials. Fi s , a e 5 min o s abiliza ion a 30 ◦C, samples we e hea ed o 250 ◦C a 15 ◦C/min. Then, he samples we e s abilized o 5 min a 250 ◦C and cooled down o −80 ◦C o e ase he he mal his o y. Then, a second hea ing amp up o 250 ◦C was ca ied ou a 15 ◦C/min. Finally, samples we e cooled down o RT a 15 ◦C/min. All es s we e pe o med unde N 2 a mosphe e ( low a e 50 ml/min), wi h a mass M. T igo L´ opez e al. Jou nal o Pho ochemis y & Pho obiology, A: Chemis y 422 (2022) 113571 3 sample o app oxima ely 15 mg. Ionic conduc i i y o he memb anes was de e mined a RT and also in a empe a u e ange om −50 ◦C o 90 ◦C. The ionic conduc i i y beha io o he elec oly es was de e mined in a NOVOCONTROL GmbH Concep 40 b oadband dielec ic spec ome e in he equency ange be ween 1 and 10 7 Hz. Disk ilms o dimensions o 16 mm diame e and a ound 200 μ m hickness we e inse ed be ween wo gold-pla ed la elec odes, he samples we e cooled down o −50 ◦C. Then, a equency sweep was ca ied ou e e y 10 ◦C hea ing up o 90 ◦C. The pho opolyme iza ion eac ions we e ca ied ou in a Biolink™ BLX-365 ype Bio-link appa a us (Vilbe Lou ma ™) by i adia ion wi h UV ligh (365 nm) o 55 min. 2.3. Film p epa a ion Fi s ly, he syn hesis o he ionic liquid used in he pho o- polyme izable o mula ion is desc ibed [15,23], (sec ion 2.3.1). Sec- ondly, he ab ica ion o he mic opo ous a amids is de ailed (sec ion 2.3.2). To conclude, he illing and pho opolyme iza ion p ocess o he o mula ion inside he po ous s uc u e o he a amids is desc ibed (sec ion 2.3.3). 2.3.1. Syn hesis o he monome 1-(2-me hac yloyloxy)e hyl-3- bu ylimidazolium bis( i luo ome hane sul onyl)imide (ILQ) 1-(2-me hac yloyloxy)e hyl-3-bu ylimidazolium bis( i luo o- me hane sul onyl)imide monome was employed as he imidazolium- based polyme izable ionic liquid. We will deno e his monome as (ILQ), o clea ly di e en ia e i om he ionic liquid (1-e hyl-3-me h- ylimidazolium b omide, named as IL) employed o ob ain he po ous s uc u e in he a amids. The syn hesis p ocess was ca ied ou in h ee s eps. Fi s , he monome 2-b omoe hyl me hac yla e (L 1 ) was syn he- ized. Secondly, he monome 1-(2-me hac yloyloxy)e hyl-3-bu ylimi- dazolium b omide (L 2 ) was ob ained o inally p epa e in he las s ep he 1-(2-me hac yloyloxy)e hyl-3-bu ylimidazolium bis( i luo o- me hane sul onyl)imide (ILQ). The syn hesis p ocedu e and cha ac e - iza ion esul s o each eac ion p oduc can be ound in de ail in one o ou p e ious wo ks [15]. 2.3.2. P epa a ion o mic opo ous a amid ilms The p epa a ion o mic opo ous a amid ilms i s ly in ol es ob aining dense a amid ilms (pu e a amid ilms illed wi h IL). A amid ibe s we e dissol ed in ho DMAc (60 ◦C), con aining 2 % w . o LiCl espec o he olume o DMAc o imp o e he solubili y o a amid ibe in DMAc. To ob ain he mic opo ous s uc u e, 1-e hyl-3-me hylimida- zolium b omide (IL) was added o he solu ion in a p opo ion o 10/ 90 w (MPIA:LI) and s i ed o 3 h. Then, he solu ion was pou ed in o a glass pla e o 20 ×20 cm and placed inside an o en a 85 ◦C du ing a leas 24 h, un il he comple e e apo a ion o he sol en . Dense ilms we e e med as 10ARA/90IL. Mic opo ous a amid ilms we e ab ica ed by simply washing dense ilms in dis illed wa e a 80 ◦C o 4 h eplacing he dis illed wa e h ee imes o emo e he IL and a he same ime, he possible aces o emaining sol en . Po ous ilms a e IL emo al we e deno ed as (10ARA/90IL)-R. I is impo an o ema k ha he p opo ion o he IL was 10/90 w (MPIA:LI) o assu e he p esence o an in e connec ed mic o-channel po ous s uc u e a e IL emo al. Lowe p opo ions o IL we e al eady es ed in a p e ious wo k, leading o closed-cell po osi y ha could limi he e iciency o he illing p ocess [25]. Using his me hodology, po ous ma e ials o a ound 100 cm 2 we e ob ained. A leas 5 discs o 16 mm diame e we e punched om he po ous ilm-shaped ma e ial o p oceed a e wa ds o he illing and polyme i- za ion o he o mula ion including ILQ inside he po ous s uc u e. Fig. S1 shows a pho og aph o a amid discs (pu e a amid ilms wi hou IL, dense a amid ilm illed wi h IL and po ous a amid ilm a e IL emo al). I is obse ed ha discs a e IL emo al p esen a high deg ee o opaci y (Fig. S1c) e idencing he gene a ion o a po ous s uc u e in which ligh is di ac ed and educing d as ically he anspa ency obse ed in pu e and dense a amids (Fig. S1a and b). Thicknesses o he discs we e a ound 200 μ m. A e age densi y alues we e calcula ed om he indi idual mea- su emen o a leas h ee discs o each ilm (pu e, dense and po ous). Al hough many di e en wo ks p esen he cha ac e iza ion o imidazolium-based ionic liquids [33], he li e a u e does no indica e he densi y o his speci ic IL. Howe e , we can es ima e he densi y o he IL using he mix u e’s law o wo-phase ma e ials, ob aining a densi y alue o he IL a ound 1.19 g/cm 3 , lying in he ange o ypical densi y alue epo ed o simila imidazolium-based ILs [34]. Densi y o po ous a amids was dec eased o 0.17 ±0.04 g/cm 3 , hus a educ ion by a ac o o app oxima ely 8 espec o pu e MPIA. 2.3.3. Pho opolyme iza ion p ocess Table 1 shows he composi ion o he solu ion employed, in which ILQ co esponds o he syn hesized polyme izable ILs, EMIM TFSI he comme cial IL, LiTFSI he li hium sal and EGDM was included as c osslinke . All he compounds lis ed in Table 1 we e ans e ed o a glass ial, degassed by ni ogen bubbling and sonica ed o 10 min. Then, 1 ml o he solu ion was injec ed in a ci cula PTFE mold, and a po ous a amid disc o 12 mm diame e was imme sed in o he p epa ed solu ion and main ained in da k and unde an oxygen- ee a mosphe e o 72 h o acili a e a homogenous illing along he disc. A e ha , he illed a amid was aken ou o he solu ion and hen d ained o emo e he esidual solu ion, and pho opolyme ized unde ni ogen a mosphe e, by i adia ion wi h UV ligh (365 nm) a RT o 55 min. Finally, he ma e ials we e d ied in acuum a 50 ◦C o 3 days o ob ain he lexible solid elec oly e. These discs we e named as ARA IMID . In a simila way, wo supplemen a y ma e ials we e p epa ed, one o hem polyme ized only wi h he mix u e o polyme izable ionic liquid, c osslinke and pho oini ia o , wi hou using EMIM TFSI and LiTFSI (named as ARA ILQ-pol ) and a second one, only illed (no polyme ized) exclusi ely wi h he ionic liquid ILQ (named as ARA ILQ- il ). I has o be poin ed ou ha in he condi ions used in his wo k, and du ing he ime scale o analysis, i was no obse ed any isible e idence o leaking o he po ous a amid memb anes swollen wi h ionic liquid o pho ocu able composi ion. The compa a i e beha io o bo h ma e ials will be analyzed o cha ac e ize he polyme iza ion o he ionic liquid inside he po ous s uc u e. Densi y o he ma e ials ob ained was 1.16 g/cm 3 o ARA ILQ- il samples, 1.42 g/cm 3 o ARA ILQ-pol samples and 1.35 g/cm 3 in he case o ARA IMID samples. Compa ing hese alues wi h he densi y o he ini ial po ous ma e ial ( ρ ≈0.17 g/cm 3 ), i is con i med ha , in all he cases, he solu ion has e ec i ely pene a ed inside he po ous channel s uc u e. The ilms p epa ed, hei composi ion and nomen- cla u e a e summa ized in Table 2. 3. Resul s and discussion The esul s sec ion is di ided in ou subsec ions. In sec ion 3.1., he mic opo ous s uc u e o a amids a e he IL emo al is analyzed h ough SEM images and he mo phological pa ame e s a e de e mined. The illing and pho opolyme iza ion p ocess o he ionic liquid ILQ Table 1 Composi ion o he pho opolyme izable o mula- ion used in he po ous a amid swelling p ocess. Ma e ial % w . ILQ 24.54 EMIM TFSI 55.26 LiTFSI 20.20 EGDM* 1.00 Pho oini ia o * 1.50 * EGDM da a is gi en in % mol wi h espec o % mol o comonome s and pho oini ia o da a is gi en in % w . wi h espec o o al weigh . M. T igo L´ opez e al. Jou nal o Pho ochemis y & Pho obiology, A: Chemis y 422 (2022) 113571 4 inside he po ous s uc u e is desc ibed in sec ion 3.2., paying a en ion o he TGA, SEM and weigh de e mina ion esul s o ARA ILQ-pol and ARA ILQ- il , o cha ac e ize he polyme iza ion p ocess. Finally, in sec ion 3.3 he ionic conduc i i y alues o he ma e ials a e p esen ed. 3.1. Po ous s uc u e A homogeneous mic opo ous s uc u e was obse ed in he a amid discs a e he IL emo al. SEM obse a ions we e aken in he c oss sec ion and also in he su ace o he ma e ials, Fig. 1. C oss sec ion SEM images o 10ARA/90IL-R discs show a homoge- neous open-cell mic opo ous s uc u e wi h an a e age po e diame e R a ound 700 nm and cell sizes o 1.5∙10 13 cells/cm 3 , Fig. 1a and b. Howe e , we mus ema k ha he de e mina ion o he mo phological pa ame e s can be di icul in open-cell s uc u es o in hese mo phol- ogies based on open in e connec ed mic o channels. Fig. 1c and d p esen he SEM images o he su ace o he po ous a amids. In his case, a egula dis ibu ion o closed po es be ween 1 and 2 μ m o diame e is obse ed. I is impo an o ema k ha his su ace po osi y has been also obse ed in simila po ous ma e ials ob- ained using ILs, such as PMMA [35]. This po osi y e y likely p omo es he illing o he ma e ials wi h he ionic liquid solu ion. 3.2. S udy o pho opolyme iza ion p ocess Radical pho opolyme izable o mula ion including he ionic liquids was unde aken by i adia ing he ma e ial embedded in he solu ion wi h UV ligh (365 nm) a RT. Polyme iza ion ime was ixed o 55 min [15,23]. This polyme iza ion ime assu ed ha UV ligh pene a ed in- side he whole hickness o he ilm (≈200 μ m), and also gua an eed ha he opaci y o he ma e ials due o he po osi y did no a ec o he polyme iza ion e iciency. The cha ac e iza ion o he illed and polyme ized a amids was ca ied ou h ough di e en echniques. Fi s , he mal s abili y o he a amids was analyzed by s anda d TGA measu emen s, in o de o e alua e he di e en he mal beha io o illed and polyme ized discs. TGA cu es o all he ma e ials p epa ed a e p esen ed in Fig. S2. The analysis o he onse deg ada ion empe a u es, Table 3, shows ha he emo al o IL is e idenced, by compa ing he onse empe a u es o 10ARA/90IL and 10ARA/90IL-R (279 and 452 ◦C, espec i ely). Also, i can be obse ed an app eciable di e ence in he onse alues om ARA ILQ- il (348 ◦C) and ARA ILQ-pol (376 ◦C). This could indica e also he o ma ion o a c osslinked s uc u e in he ARA ILQ-pol de i ed o he polyme iza ion p ocess o he ILQ. I is also no iced ha in e ms o he mal deg ada ion, ARA IMID and ARA ILQ-pol show he same beha io Table 2 Composi ion and nomencla u e o he ilms. Film Composi ion Cha ac e is ics MPIA IL ILQ EMIM TFSI LiTFSI EGDM Pho oi 10ARA/90IL ✓ ✓ – – – – – Dense (A amid +IL) (10ARA/90IL-R ✓ – – – – – – Po ous (A e IL emo al) ARA IMID ✓ – ✓ ✓ ✓ ✓ ✓ Filled wi h o mula ion (Table 1) and polyme ized ARA ILQ- il ✓ – ✓ – – – – Filled wi h ILQ and non-polyme ized ARA ILQ-pol ✓ – ✓ – – ✓ ✓ Filled wi h ILQ and polyme ized Fig. 1. SEM images o he 10ARA/90IL-R discs: a) and b) c oss sec ion; c) and d) su ace. M. T igo L´ opez e al. Jou nal o Pho ochemis y & Pho obiology, A: Chemis y 422 (2022) 113571 5 (onse empe a u es a e 381 and 376 ◦C, espec i ely) as consequence o he polyme iza ion o ILQ, since all he imidazolium ILs con aining [TFSI] anion a e he mos s able ILs [36]. Also, he in luence o he anion in he imidazolium ing o he ionic liquid is e idenced compa ing he onse empe a u es o 10ARA/90IL (279 ◦C) which con ains 1-e hyl-3- me hylimidazolium b omide, and ARA ILQ- il (348 ◦C), con aining 1-(2- me hac yloyloxy)e hyl-3-bu ylimidazolium bis( i luo ome hane sul o- nyl)imide. In ARA IMID , ARA ILQ- il and ARA ILQ-pol ma e ials, he p esence o he ILQ is de ec ed, and onse empe a u e alues a e in he same ange (be ween 350 ◦C and 380 ◦C), co esponding o deg ada ion o he side g oups (such as imidazolium ca ions) o he IL oge he wi h he deg ada ion o he main chain o he a amid ma ix. By DSC analysis, he glass ansi ion o he polyme ized ILQ embedded in he po ous a amid ARA ILQ-pol is de ec ed a ound −20 ◦C. This low glass ansi ion alue o he polyme ized ionic liquid makes possible he ion anspo inside he ma e ial, due o he good mobili y o he polyme chains a RT. In he case o 10ARA/90IL, he mel ing poin o 1-e hyl-3-me hylimidazolium b omide is obse ed a ound 75 ◦C, close o he alue epo ed in he bibliog aphy by F edlake e al. [17] and also o he same o de ha he alue measu ed in ou p e ious wo ks in which po ous a amids we e also ob ained using his speci ic ionic liquid [37]. I is also in e es ing o ema k ha no plas iciza ion e ec o he ionic liquids in he a amid ma ix was obse ed, indica ing ha he ole o he a amid is exclusi ely ac ing as suppo o he mixing o ionic liquids, ob aining a ma e ial in which a amid and ionic liquid phases a e comple ely sepa a ed, wi hou any chemical in e ac ion. On he o he hand, we could no obse e any he mal ansi ion associa ed o he ARA IMID ilm (composed o comme cial ionic liquid EMIM TFSI and li hium sal LiTFSI oge he wi h polyme izable ionic liquid ILQ). Al hough we did expec o obse e a simila ansi ion o he one obse ed in in ARA ILQ-pol ilm, i may be due o he low p opo ion o ILQ employed in he polyme izable solu ion (a ound 24 %, see Table 1), and his ansi ion could no be de ec ed. SEM obse a ions o illed and polyme ized a amids be o e and a e washing wi h DCM we e ca ied ou o isually de ec he p esence o he polyme ized ionic liquid ILQ, and he emo al o he monome wi h DCM. Fo compa ison pu poses, he SEM images o he ini ial po ous a amid 10ARA/90IL-R, a e included. Fig. 2 p esen s he SEM images o he c oss sec ion and su ace o he s a ing po ous a amid (10ARA/90IL)-R), he illed a amid (ARA ILQ- il ) and he polyme ized a amid (ARA ILQ-pol ). Fig. 2a and d show he po ous mo phology o he s a ing po ous a amid, and a e illing wi h he polyme izable ionic liquid ILQ a e he imme sion in he polyme izable solu ion, Fig. 2b and e o he ARA ILQ- il a amid. In he c oss sec ion and su ace image, i is de ec ed ha he illing p ocess is comple ed along he whole po ous mo phology. Howe e , when polyme iza ion occu s, he mo phology obse ed changes d as ically. In he c oss-sec ion image o ARA ILQ-pol , Fig. 2c, he po ous s uc u e disappea s, eme ging a dense su ace in which he polyme ized ILQ is loca ed in sub-mic on egions. This egion, dis ibu ed homogeneously, could co espond o agmen s o a amid co e ed by he polyme ized ILQ. On he con a y, su ace mo phology o he polyme ized a amid, Fig. 2 o he ARA ILQ-pol , does no di e g ea ly om he mo phology obse ed in he illed a amid, Fig. 2e, and a dense su ace mo phology is de ec ed. The di e ence be ween he c oss-sec ion and su ace images in ARA ILQ-pol a amid could be explained as ollows, in he case o su ace obse a ions, he e is a hin laye o IL polyme ized homogeneously, Fig. 2 , bu in he inne po osi y, i could be obse e ha he po es ha e been comple ely illed wi h he IL, Fig. 2c. The e ec o he washing p ocess wi h DCM is p esen ed in he SEM Table 3 The mal p ope ies o a amids in oxidan a mosphe e (syn he ic ai ) (ex apola ed onse empe a u e is de ined as he empe a u e a which he decomposi ion o he ma e ial begins). Film Ex apola ed onse empe a u a (◦C) 10ARA/90IL 279 10ARA/90IL-R 452 ARA IMID 381 ARA ILQ- il 348 ARA ILQ-pol 376 Fig. 2. SEM mic og aphs o he a amids: a) c oss sec ion o 10ARA/90IL-R; b) c oss sec ion o ARA ILQ- il ; c) c oss sec ion o ARA ILQ-pol ; d) su ace o (0ARA/90IL-R; e) su ace o ARA ILQ- il ; and ) Su ace o ARA ILQ-pol. M. T igo L´ opez e al. Jou nal o Pho ochemis y & Pho obiology, A: Chemis y 422 (2022) 113571 6 images in Fig. 3. Fig. 3a p esen s he su ace o he illed a amid ARA ILQ- il a e washing wi h DCM, in which he po osi y su ace is e ealed again due o he emo al o he ILQ monome . On he o he hand, Fig. 3b shows ha washing wi h DCM does no a ec he polyme ized mem- b ane ARA ILQ-pol (no po osi y appea s, and dense su ace is obse ed in he same way ha in he illed a amid, see Fig. 2 ). These esul s would con i m ha pho opolyme iza ion o he ILQ monome akes place in- side he po ous s uc u e o he a amids. Weigh measu emen s we e ca ied ou o analyze wo di e en phenomena. Fi s , he illing abili y o po ous a amids is analyzed, which can be compa ed as an es ima i e p ocess o he swelling pe - cen age in dense a amids. The second phenomenon is in ended o s udy he e iciency o he pho opolyme iza ion o he ILQ inside he po ous s uc u e. This can be e idenced simply by measu ing he weigh a i- a ion o a illed and a polyme ized sample be o e and a e washing wi h DCM. Due o he high solubili y in DCM o he ILQ monome and he insolubili y o he polyme ized ILQ, he polyme iza ion p ocess can be cha ac e ized. Beginning wi h he illing beha io , Table 4 p esen s he weigh a ia ion o a po ous a amid disc (ARA IMID ) be o e and a e he illing p ocess desc ibed in Sec ion 3.2. Da a p esen ed in Table 4 esul s in a illing pe cen age o a ound 465 %. This alue is conside ably highe han illing pe cen ages obse ed in dense a amids, which ha dly exceed alues a ound 10 % in aqueous solu ions [38]. This da a con i ms he posi i e in luence o he su ace po osi y in he illing abili y o a amids, enhancing d as ically he quan i y o pho opolyme izable o mula ion, and o ins ance he con en o ionic-liquids (ILQ and EMIM TFSI) and Li hium sal , which could be embedded in he a amid po ous s uc u e. Secondly, he e iciency o he polyme iza ion p ocess is simply analyzed by measu ing he quan i y o un eac ed ILQ monome ha is elimina ed h ough washing he ma e ial in DCM. Fo his pu pose, masses o ARA ILQ-pol and ARA ILQ- il discs we e measu ed be o e and a e washing wi h DCM. Resul s showed ha mass loss pe cen age in ARA ILQ- il was a ound 77 % in ela ion wi h he o al weigh o ARAILQ- il disc, which co esponds o he ILQ monome , and eco e ing ully he ini ial mass. On he o he hand, mass loss pe cen age in ARA ILQ-pol was p ac- ically negligible (a ound 1.5 %), indica ing he absence o un eac ed monome a e he polyme iza ion p ocess. 3.3. Ionic conduc i i y The alues o conduc i i y ( σ ) a 25 ◦C in all he a amids p epa ed a e lis ed in Table 5, and i was de e mined a he alue o equency whe e a maximum in an δ g aph was obse ed. Fig. S3 shows he conduc i i y and an δ a ia ion in he equency ange. The analysis o he esul s can be ca ego ized in h ee g oups, in e ms o hei conduc i i y alues. In he i s g oup, i could be compa ed he s a ing po ous a amid, 10ARA/90IL-R, wi h a p ac ically negligible ionic conduc i i y, oge he wi h he a amid wi h he com- me cial ionic liquid embedded, 10ARA/90IL, wi h a high conduc i i y alue o 1.19 ×10 -3 S/cm, owing o he ionic liquid phase dis ibu ed in he a amid ma ix, which was obse ed h ough RAMAN mapping es s in ou p e ious wo ks [25]. Despi e his good alue, in hese ma e ials he liquid phase could mig a e ou o he memb ane as ime goes by. Also, he o al amoun o comme cial ionic liquid in each memb ane disc is oo high, a ound 225 mg/disc. Secondly, i is he e o e impo an o s and ou he ionic conduc i i y alues o only illed ma e ial (ARA ILQ- il ) along wi h he a amid illed wi h he ionic liquid ILQ and polyme ized (ARA ILQ-pol ). While he ionic conduc i i y o illed memb ane (ARA ILQ- il ) is in he ange o he liquid elec oly es (0.244 ×10 -3 S/cm), in he case o he polyme ized a amid (ARA ILQ-pol ) he alue d ops down o 0.35 ×10 -6 S/cm. This esul would be due o he ac ha in he case o ARA ILQ-pol , he IL is ancho ed o he polyme ma ix and he ionic mobili y would be d as ically hinde ed and as consequence, he ionic conduc i i y dec eases [21] (see Fig. S4a o he ESI). Las ly, i mus be s essed he ionic conduc i i y alue o he po ous a amid con aining he polyme izable solu ion (ionic liquid ILQ and EMIM TFSI, and LiTFSI) and UV i adia ed, ARA IMID . This is an in e - es ing s a egy in he p epa a ion o IL-based elec oly es, in o de o inc ease he solid elec oly e conduc i i y [15]. In his case, he p esence o ILQ is o g ea impo ance, no only because o hei well-known ad an ages as a as secu i y isks, bu also due o he good chemical Fig. 3. SEM mic og aphs o he su ace a amids a e washing wi h DCM. a)ARA ILQ- il ; b)ARA ILQ-pol. Table 4 Filling pe cen age o po ous a amid discs a e he expe imen al p ocedu e desc ibed in Sec ion 3.2. (Discs imme sed in o pho ocu able solu ion and UV i adia ed a 365 nm). Ini ial mass (mg) Final mass (mg) ILQ (mg) EMIM TFSI (mg) LiTFSI (mg) Filling (%) 20 113 23 51 19 465 Table 5 Conduc i i y alues ob ained in a amids a 25 ◦C. Film σ (S/cm) 10ARA/90IL 1.19 ×10 -3 10ARA/90IL-R 7.37 ×10 -8 ARA IMID 1.23 ×10 -3 ARA ILQ- il 0.24 ×10 -3 ARA ILQ-pol 0.35 ×10 -6 M. T igo L´ opez e al. Jou nal o Pho ochemis y & Pho obiology, A: Chemis y 422 (2022) 113571 7 compa ibili y wi h he IL (EMIM TFSI) o ming s able ion-gels wi h high conduc i i y alues [20]. In his ins ance, a ema kable ionic conduc- i i y o up o 1.23 ×10 -3 S/cm a 25 ◦C is ob ained, e y closely o hei analogous a amid wi h ionic liquid (10ARA/90IL). Fu he mo e, his alue is in he ange o he liquid elec oly es, such as he conduc i i y a 25 ◦C o liquids like EMIFSI (15.4 ×10 -3 S/cm) [23], EMIMTFSI used in his wo k (5.3 ×10 -3 S/cm) and o elec oly es based on EMIMTFSI and LiTFSI ( alues a ound 2.6–3.7 10 -3 S/cm depending on he composi ion) [39]. In addi ion o his, he quan i y o comme cial IL in ARA IMID is conside ably lowe (a ound 70 mg). By compa ing he ionic conduc i i y o he s a ing 10ARA/90IL and ARA IMID a amids, he ob ained alues a e simila , e en sligh ly highe in ARA IMID a amid. A his poin , i is impo an o ema k ha he quan i y o liquid IL (1-e hyl-3-me hylimidazolium b omide) in 10ARA/90IL disc is a ound 225 mg (90% o he o al weigh ), whe eas his quan i y in ARA IMID is conside ably lowe , a ound 70 mg (65% o he o al weigh ). Also, i mus poin ed ou ha in in ARA IMID only 51 mg (45% o o al weigh ) co espond o EMIMTFSI which emained as liquid phase in he memb ane, since ILQ is pho opolyme ized. Mo eo e , in he case o 10ARA/90IL, he conduc i i y a 25 ◦C o pu e 1-e hyl-3-me hylimida- zolium b omide is a ound 0.68 ×10 -3 S/cm [40], whe eas in he case o TFSI-based ionic liquids, his alue is highe (be ween 3 and 10 ×10 -3 S/cm) [41]. This indica es ha he p ocess o illing and “in si u” pho- opolyme iza ion h ough he in e connec ed mic ochannel po ous s uc u e can educe d as ically he amoun o comme cial ionic liquid necessa y o ob ain high-conduc i e ma e ials, and o ins ance would con ibu e o de elop sa e sys ems. The mal dependence o he ionic conduc i i y o ARA IMID was also analyzed, indica ing a empe a u e dependence cha ac e is ic o a iscous liquid in which ionic conduc i i y is go e ned by iscosi y (µ) o he sys em in he whole empe a u e ange. Fig. S5 o he ESI shows he e olu ion o he ionic conduc i i y o ARA IMID be ween −50 ◦C and 90 ◦C, whe e he conduc i i y inc eased wi h empe a u e up o alues a ound 10 -2 S/cm. 4. Conclusions This wo k p esen s a no el ou e o ob ain lexible solid-gel polyme elec oly es based on po ous a amids, and by using pho opolyme iza ion o ionic liquids o ill he po ous s uc u e. The memb anes p epa ed combine he excellen he mal and mechanical p ope ies o he a amids wi h high ionic conduc i i y alues o ionic liquids. The de e mina ion o he ionic conduc i i y con i med ha alues lied in he ange o cu en solid-gel polyme ic elec oly es epo ed in he li e a u e. Also, he esul s would indica e ha ion mobili y is no only due o he in insic conduc i i y o he ionic liquid, bu i is also enhanced by he in e connec ed po osi y o he a amid, hen inc easing easily hei e i- ciency as ion-conduc ing ma e ials, sugges ing a ela ion be ween he po ous s uc u e o he a amid and he ionic conduc i i y o he mem- b ane. In addi ion, compa ed o o he solid-gel polyme elec oly es, ou me hod in ol es lowe quan i ies o IL o ob ain high ionic conduc i i y alues, hen imp o ing he e iciency and sa e y o he polyelec oly es employed in high-pe o mance Li-ion ba e ies. CRediT au ho ship con ibu ion s a emen M. T igo L´ opez: Me hodology, In es iga ion. J.A. Regle o Ruiz: Concep ualiza ion, Supe ision, Visualiza ion, W i ing – e iew & edi ing. J.L. Pablos: Me hodology, In es iga ion, Visualiza ion, W i ing – e iew & edi ing. D.E. Ciu duc: In es iga ion. T. Co ales: Concep- ualiza ion, Supe ision, Visualiza ion, W i ing – e iew & edi ing, Funding acquisi ion. F.C. Ga cía: Concep ualiza ion, Visualiza ion, W i ing – e iew & edi ing, W i ing – e iew & edi ing. J.M. Ga cía: Concep ualiza ion, Supe ision, W i ing – e iew & edi ing, Funding acquisi ion. Decla a ion o Compe ing In e es The au ho s decla e ha hey ha e no known compe ing inancial in e es s o pe sonal ela ionships ha could ha e appea ed o in luence he wo k epo ed in his pape . Acknowledgmen s We g a e ully acknowledge he inancial suppo p o ided by FEDER (Fondo Eu opeo de Desa ollo Regional) and bo h he Spanish Minis e io de Economía, Indus ia y Compe i i idad (MAT2017-84501-R and MAT2017-88923-P), he Conseje ía de Educaci´ on-Jun a de Cas illa y Le´ on (BU306P18) and he Spanish Minis e io de Ciencia e Inno aci´ on (PID2019-108583RJ-I00/AEI/10.13039/501100011033). Appendix A. Supplemen a y da a Supplemen a y da a o his a icle can be ound online a h ps://doi. o g/10.1016/j.jpho ochem.2021.113571. Re e ences [1] I. Osada, H. deV ies, B. Sc osa i, S. Passe ini, Ionic-Liquid-Based Polyme Elec oly es o Ba e y Applica ions, Angew. Chemie - In . Ed. 55 (2) (2016) 500–513, h ps://doi.o g/10.1002/anie.201504971. [2] D. Mece eyes, L. Po ca elli, N. Casado, Inno a i e Polyme s o Nex -Gene a ion Ba e ies, Mac omol. Chem. Phys. 221 (4) (2020) 1900490, h ps://doi.o g/ 10.1002/macp.201900490. [3] N.K. Ka an, D.K. P adhan, R. Thomas, B. Na esan, R.S. Ka iya , Solid polyme elec oly es based on polye hylene oxide and li hium i luo o- me hane sul ona e (PEO–LiCF3SO3): Ionic conduc i i y and dielec ic elaxa ion, 179 (2008) 689–696. doi:10.1016/j.ssi.2008.04.034. [4] B.W. Zewde, S. Admassie, J. Zimme mann, S. Is o , Enhanced Li hium Ba e y wi h Polye hylene Oxide-Based Elec oly e Con aining Silane – Al2O3 Ce amic Fille , 3 (2013) 1–7. doi:10.1002/cssc.201300296. [5] D. Zhou, X. Mei, J. Ouyang, Ionic Conduc i i y Enhancemen o Polye hylene Oxide-LiClO 4 Elec oly e by Adding Func ionalized Mul i-Walled, Ca bon Nano ubes 115 (33) (2011) 16688–16694, h ps://doi.o g/10.1021/jp203224b. [6] H. Yoon, G.H. Lane, Y. Shekibi, P.C. Howle , M. Fo sy h, A.S. Bes , D. R. MacFa lane, Li hium elec ochemis y and cycling beha iou o ionic liquids using cyano based anions, Ene gy En i on. Sci. 6 (2013) 979–986, h ps://doi.o g/ 10.1039/c3ee23753b. [7] S. Menne, J. Pi es, M. Anou i, A. Balducci, P o ic ionic liquids as elec oly es o li hium-ion ba e ies, Elec ochem. Commun. 31 (2013) 39–41, h ps://doi.o g/ 10.1016/j.elecom.2013.02.026. [8] M.J. Pa k, I. Choi, J. Hong, O. Kim, Polyme elec oly es in eg a ed wi h ionic liquids o u u e elec ochemical de ices, J. Appl. Polym. Sci. 129 (5) (2013) 2363–2376, h ps://doi.o g/10.1002/app.39064. [9] A. Vall´ ee, S. Besne , J. P ud’Homme, Compa a i e s udy o poly(e hylene oxide) elec oly es made wi h LiN(CF 3 SO 2 ) 2 , LiCF 3 SO 3 and LiClO 4 : The mal p ope ies and conduc i i y beha iou , Elec ochim. Ac a. 37 (1992) 1579–1583, h ps://doi. o g/10.1016/0013-4686(92)80115-3. [10] A. Tsu umaki, J. Kagimo o, H. Ohno, P ope ies o polyme elec oly es composed o poly(e hylene oxide) and ionic liquids acco ding o ha d and so acids and bases heo y, Polym. Ad . Technol. 22 (2011) 1223–1228, h ps://doi.o g/10.1002/ pa .1931. [11] S.K. Chau asia, R.K. Singh, S. Chand a, Ion-polyme and ion-ion in e ac ion in PEO-based polyme elec oly es ha ing complexing sal LiClO 4 and/o ionic liquid, [BMIM][PF 6 ], J. Raman Spec osc. 42 (12) (2011) 2168–2172, h ps://doi.o g/ 10.1002/j s. 42.1210.1002/j s.2999. [12] Z. Xue, D. He, X. Xie, Poly(e hylene oxide)-based elec oly es o li hium-ion ba e ies, J. Ma e . Chem. A. 3 (38) (2015) 19218–19253, h ps://doi.o g/ 10.1039/C5TA03471J. [13] M.Z. Ku ian, M.F. Aziz, M.F. Shuku , A.S. Rahim, N.E. A i in, N.E.A. Shuhaimi, S. R. Majid, R. Yahya, A.K. A o , PMMA-LiBOB gel elec oly e o applica ion in li hium ion ba e ies, Solid S a e Ionics 208 (2012) 36–42, h ps://doi.o g/ 10.1016/j.ssi.2011.11.032. [14] R.C. Ag awal, G.P. Pandey, Solid polyme elec oly es: Ma e ials designing and all- solid-s a e ba e y applica ions: An o e iew, J. Phys. D. Appl. Phys. 41 (22) (2008) 223001, h ps://doi.o g/10.1088/0022-3727/41/22/223001. [15] J.L. Pablos, N. Ga cía, L. Ga ido, F. Ca alina, T. Co ales, P. Tiemblo, Polyca ionic sca olds o Li-ion anion exchange anspo in ion gel polyelec oly es, J. Ma e . Chem. A. 6 (24) (2018) 11215–11225, h ps://doi.o g/10.1039/C8TA03134G. [16] M. Egashi a, H. Todo, N. Yoshimo o, M. Mo i a, J.-I. Yamaki, Func ionalized imidazolium ionic liquids as elec oly e componen s o li hium ba e ies, J. Powe Sou ces. 174 (2) (2007) 560–564, h ps://doi.o g/10.1016/j. jpowsou .2007.06.123. M. T igo L´ opez e al. Jou nal o Pho ochemis y & Pho obiology, A: Chemis y 422 (2022) 113571 8 [17] C.P. F edlake, J.M. C os hwai e, D.G. He , S.N.V.K. Aki, J.F. B ennecke, The mophysical p ope ies o imidazolium-based ionic liquids, J. Chem. Eng. Da a. 49 (4) (2004) 954–964, h ps://doi.o g/10.1021/je034261a. [18] H.L. Ngo, K. LeComp e, L. Ha gens, A.B. McEwen, The mal p ope ies o imidazolium ionic liquids, The mochim. Ac a. 357–358 (2000) 97–102, h ps:// doi.o g/10.1016/S0040-6031(00)00373-7. [19] M.D. G een, T.E. Long, Designing imidazole-based ionic liquids and ionic liquid monome s o eme ging echnologies, Polym. Re . 49 (4) (2009) 291–314, h ps:// doi.o g/10.1080/15583720903288914. [20] A.S. Shaplo , R. Ma cilla, D. Mece eyes, Recen Ad ances in Inno a i e Polyme Elec oly es based on Poly(ionic liquid)s, Elec ochim. Ac a. 175 (2015) 18–34, h ps://doi.o g/10.1016/j.elec ac a.2015.03.038. [21] S. Washi o, M. Yoshizawa, H. Nakajima, H. Ohno, Highly ion conduc i e lexible ilms composed o ne wo k polyme s based on polyme izable ionic liquids, Polyme (Guild ). 45 (5) (2004) 1577–1582, h ps://doi.o g/10.1016/j. polyme .2004.01.003. [22] Y. Aiha a, M. Kodama, K. Nakaha a, H. Okise, K. Mu a a, Cha ac e is ics o a hin ilm li hium-ion ba e y using plas icized solid polyme elec oly e, J. Powe Sou ces. 65 (1-2) (1997) 143–147, h ps://doi.o g/10.1016/S0378-7753(96) 02605-5. [23] G.B. Appe ecchi, G.-T. Kim, M. Mon anino, M. Ca ewska, R. Ma cilla, D. Mece eyes, I. De Mea za, Te na y polyme elec oly es con aining py olidinium-based polyme ic ionic liquids o li hium ba e ies, J. Powe Sou ces. 195 (11) (2010) 3668–3675, h ps://doi.o g/10.1016/j. jpowsou .2009.11.146. [24] J.L. Pablos, N. Ga cía, L. Ga ido, J. Guzm´ an, F. Ca alina, T. Co ales, P. Tiemblo, Highly e icien mixed Li + anspo in ion gel polyca ionic elec oly es, J. Memb. Sci. 545 (2018) 133–139, h ps://doi.o g/10.1016/j.memsci.2017.08.073. [25] B.S. Pascual, M. T igo-L´ opez, J.A. Regle o Ruiz, J.L. Pablos, J.C. Be olín, C. Rep esa, J.V. Cue as, F.C. Ga cía, J.M. Ga cía, Po ous a oma ic polyamides he easy and g een way, Eu . Polym. J. 116 (2019) 91–98, h ps://doi.o g/10.1016/j. eu polymj.2019.03.058. [26] H. Lin, S. Zhang, J.-K. Sun, M. An onie i, J. Yuan, Poly (ionic liquid)s wi h enginee ed nanopo es o ene gy and en i onmen al applica ions, Polyme (Guild ). 202 (2020) 122640, h ps://doi.o g/10.1016/j.polyme .2020.122640. [27] J. Zhang, B. Sun, X. Huang, S. Chen, G. Wang, Honeycomb-like po ous gel polyme elec oly e memb ane o li hium ion ba e ies wi h enhanced sa e y, Sci. Rep. 4 (2014) 1–7, h ps://doi.o g/10.1038/s ep06007. [28] R. Miao, B. Liu, Z. Zhu, Y. Liu, J. Li, X. Wang, Q. Li, PVDF-HFP-based po ous polyme elec oly e memb anes o li hium-ion ba e ies, J. Powe Sou ces 184 (2) (2008) 420–426, h ps://doi.o g/10.1016/j.jpowsou .2008.03.045. [29] R. Rohan, Y. Sun, W. Cai, K. Pa eek, Y. Zhang, G. Xu, H. Cheng, Func ionalized meso/mac o-po ous single ion polyme ic elec oly e o applica ions in li hium ion ba e ies, J. Ma e . Chem. A. 2 (9) (2014) 2960–2967, h ps://doi.o g/10.1039/ C3TA13765A. [30] D. Zhou, R. Liu, J. Zhang, X. Qi, Y.-B. He, B. Li, Q.-H. Yang, Y.-S. Hu, F. Kang, Nano Ene gy In si u syn hesis o hie a chical poly(ionic liquid)-based solid elec oly es o high-sa e y li hium-ion and sodium-ion ba e ies, Nano Ene gy 33 (2017) 45–54, h ps://doi.o g/10.1016/j.nanoen.2017.01.027. [31] L. Oli ei a-Salmazo, A. Lopez-Gil, F. Sil a-Bellucci, A.E. Job, M.A. Rod iguez- Pe ez, Na u al ubbe oams wi h aniso opic cellula s uc u es: Mechanical p ope ies and modeling, Ind. C ops P od. 80 (2016) 26–35, h ps://doi.o g/ 10.1016/j.indc op.2015.10.050. [32] J.A.R. Ruiz, S. Vallejos, B.S. Pascual, C. Ramos, S. Bel ´ an, F.C. Ga cía, J.M. Ga cía, Mic ocellula polyme ilms based on c oss-linked 1- inyl-2-py olidone and me hyl me hac yla e, J. Supe c i . Fluids. 140 (2018) 270–278, h ps://doi.o g/ 10.1016/j.sup lu.2018.07.011. [33] D. San os, M. San os, E. F anceschi, C. Da i a, A. Ba ison, S. Ma edi, Expe imen al Densi y o Ionic Liquids and The modynamic Modeling wi h G oup Con ibu ion Equa ion o S a e Based on he La ice Fluid Theo y, J. Chem. Eng. Da a. 61 (1) (2016) 348–353, h ps://doi.o g/10.1021/acs.jced.5b00592. [34] R.L. Ga das, M.G. F ei e, P.J. Ca alho, I.M. Ma ucho, I.M.A. Fonseca, A.G. M. Fe ei a, J.A.P. Cou inho, High-p essu e densi ies and de i ed he modynamic p ope ies o imidazolium-based ionic liquids, J. Chem. Eng. Da a. 52 (1) (2007) 80–88, h ps://doi.o g/10.1021/je060247x. [35] M. T igo-L´ opez, S. Vallejos, J.A. Regle o Ruiz, C. Ramos, S. Bel ´ an, F.C. Ga cía, J. M. Ga cía, Fab ica ion o mic opo ous PMMA using ionic liquids: An imp o ed ou e o classical ScCO 2 oaming p ocess, Polyme (Guild ). 183 (2019) 121867, h ps://doi.o g/10.1016/j.polyme .2019.121867. [36] Y. Cao, T. Mu, Comp ehensi e in es iga ion on he he mal s abili y o 66 ionic liquids by he mog a ime ic analysis, Ind. Eng. Chem. Res. 53 (20) (2014) 8651–8664, h ps://doi.o g/10.1021/ie5009597. [37] M. T igo-L´ opez, S. Vallejos, J.A. Regle o Ruiz, A. Ga cía-G´ omez, M. Sea a- Ma ínez, F.C. Ga cía, J.M. Ga cía, High-pe o mance nanopo ous a amid ilms ein o ced wi h unc ionalized ca bon nanocha ges using ionic liquids, Polyme (Guild ). 202 (2020) 122629, h ps://doi.o g/10.1016/j.polyme .2020.122629. [38] J.A. Regle o Ruiz, M. T igo-L´ opez, F.C. Ga cía, J.M. Ga cía, Func ional a oma ic polyamides, Polyme s (Basel) 9 (2017), h ps://doi.o g/10.3390/polym9090414. [39] M. Ke ne , N. Plylahan, J. Schee s, P. Johansson, Ionic liquid based li hium ba e y elec oly es: undamen al bene i s o u ilising bo h TFSI and FSI anions? Phys. Chem.Chem.Phys.,17 (2015) 19569–1958. doi: 10.1039/c5cp01891a. [40] J. Vila, C. F anjo, J.M. Pico, L.M. Va ela, O. Cabeza, Tempe a u e Beha io o he Elec ical Conduc i i y o Emim-Based Ionic Liquids in Liquid and Solid S a es, Po ugaliae, Elec ochimica Ac a 25 (1) (2007) 163–172. [41] Y. Fu, X. Cui, Y. Zhang, T. Feng, J. He, X. Zhang, X. Bai, Q. Cheng, Measu emen and Co ela ion o he Elec ical Conduc i i y o he Ionic Liquid [BMIM][TFSI] in Bina y O ganic Sol en s, J. Chem. Eng. Da a. 63 (5) (2018) 1180–1189, h ps:// doi.o g/10.1021/acs.jced.7b00646. M. T igo L´ opez e al.