Preparation and properties of novel binary and ternary highly amorphous poly(vinyl alcohol)-based composites with hybrid nanofillers

1 Vol.:(0123456789) Scien i ic Repo s | (2023) 13:19126 | h ps://doi.o g/10.1038/s41598-023-46083-2 www.na u e.com/scien i ic epo s P epa a ion and p ope ies o no el bina y and e na y highly amo phous poly( inyl alcohol)‑based composi es wi h hyb id nano ille s Anas asiia S epu a 1*, Ma ej Mičušik 1, Fede ico Oli ie i 2, Genna o Gen ile 2, Ma ino La o gna 2,3, Mau izio A ella 2, Edi a Ma yso á 4, Ja mila Vilčáko á 5 & Má ia Omas o á 1* Sma p o ec i e coa ings and de ices a e cu en ly o g ea in e es . In pa icula , hey can abso b o e lec ha m ul wa es o elec omagne ic in e e ence (EMI). In his wo k, no el bina y and e na y composi es wi h highly amo phous poly( inyl alcohol) (HAVOH) as a ma ix and single‑walled ca bon nano ubes (SWCNTs) and MXenes as nano ille s we e p epa ed. HAVOH is a ecen ly pa en ed kind o poly( inyl alcohol) (PVOH) ha was modi ied wi h diol monome s. MXenes a e a new ype o ino ganic wo‑dimensional (2D) nanopa icle consis ing o ca bides, ni ides and ca boni ides. Th ee se ies o composi es, HAVOH/SWCNTs, HAVOH/MXenes and HAVOH/SWCNTs/MXenes, we e p epa ed using he sol en cas ing me hod. Samples we e es ed wi h a ious me hods o s udy hei s uc u e, elec ical p ope ies, he mal beha io and EMI‑shielding p ope ies. HAVOH/3.0 w .% SWCNTs/3.0 w .% MXene specimens e ealed a shielding e ec i eness o 55 dB, which is 122 imes be e han ha o he nea ma ix. These esul s a e p omising o he ab ica ion o ilms wi h p o ec i e e ec s agains EMI. Demand o inno a i e polyme ic composi es is con inually g owing. The p epa a ion o his class o ma e i- als, especially low-cos and high-pe o mance polyme ic composi es, is s ill a challenge o esea che s. An impo an ac o is also he selec ion o he polyme ic ma ix. Mos polyme s equi e he u iliza ion o some o ganic sol en s o hei dissolu ion, and la ge-scale p oduc ion is o en no en i onmen ally accep able. Thus, polyme ic composi es p epa ed wi h sol en cas ing using wa e -soluble ma e ials ha e be e oppo uni ies o applica ion. The e a e ew wa e -soluble polyme s p oduced on a la ge scale. Among hem, one o he mos ele an is poly( inyl alcohol) (PVOH). Among di e en PVOH ypes, ecen ly, a modi ied PVOH con aining diol monome s named highly amo phous poly( inyl alcohol) (HAVOH), adema k G-Polyme , was p oduced1. The main ad an ages o HAVOH o e ypical PVOH a e i s semic ys alline na u e, excellen wa e solubili y, good mel p ocessing by ex usion and low oxygen pe meabili y bu poo wa e ba ie esis ance, which makes i ha d o use in ood packaging, equi ing he u iliza ion o addi i es as well as c osslinke s2–4. On he o he hand, HAVOH can be used o polyme ic nanocomposi e p epa a ion. As shown by Dona o e al.3, HAVOH ep e- sen s an e ec i e ma ix o he ealiza ion o mul i unc ional nanocomposi es wi h good elec ical, mechanical and he mal p ope ies. Besides ha , HAVOH was applied as a ma ix o he p epa a ion o composi es wi h di e en ille s, such as mul iwalled ca bon nano ubes (MWCNTs)5, g aphi e6, g aphene oxide7, clay2, silica3, cellulose8, and single-walled ca bon nano ubes (SWCNTs)9,10. In some cases, i is di icul o ind a sol en ha is sui able o bo h HAVOH dissolu ion and ille dispe sion, and speci ic me hods a e equi ed o p ocess he nanocomposi e o mula ion. San illo e al.5, who used MWCNTs as ille s, p e iously dispe sed nano ubes in OPEN 1Polyme Ins i u e o Slo ak Academy o Sciences, Dúb a ská ces a 9, 845 41 B a isla a, Slo akia. 2Ins i u e o Polyme s Composi es and Bioma e ials, Na ional Resea ch Council o I aly, Via Campi Fleg ei 34, 80078 Pozzuoli (Naples), I aly. 3Ins i u e o Polyme s Composi es and Bioma e ials, Na ional Resea ch Council o I aly, Piazzale En ico Fe mi 1, 80055 Po ici (Naples), I aly. 4SYNPO akcio á společnos , S. K. Neumanna 1316, 532 07 Pa dubice V, Czech Republic. 5Facul y o Technology, Tomas Ba a Uni e si y in Zlín, Va ečko a 5669, 760 01 Zlín, Czech Republic. *email: [email p o ec ed]; [email p o ec ed] 2 Vol:.(1234567890) Scien i ic Repo s | (2023) 13:19126 | h ps://doi.o g/10.1038/s41598-023-46083-2 www.na u e.com/scien i ic epo s/ THF ( e ahyd o u an) wi h he addi ion o an ionic liquid, enabling hem o in e ac wi h he selec ed ille . When HAVOH was added, a s able dispe sion o polyme coa ed wi h ille was o med, as HAVOH was no soluble in he a o emen ioned sol en , bu i o med hyd ogen bonds wi h he applied ionic liquid (BenzImCl— 1-Benzyl-3-me hyl-imidazolium chlo ide). The p epa ed samples showed good elec ical conduc i i y, 0.79S/ cm and we e p ocessed by 3D p in ing, ob aining e ec i e EMI-shielding sys ems. In he las decade ising numbe o di e en kinds o de ices, expanding o a eas ( e i o ies) o co e wi h wi eless local a ea ne wo ks and ada s, signi ican ly inc eased he le el o so-called "elec ic ield pollu ion". I c ea es elec omagne ic adia ion due o adio wa es and mic owa e adia ion, which is emi ed by all elec onic de ices, pa icula ly hose ha ope a e in he adio wa e and mic owa e ange o equencies (e.g., cell phones). Consequen ly, such phenomenon causes elec osmog. O g ea conce n is ha he adia ion in e e es wi h elec- onics, due o he in e ac ion o he elec ons in he me al conduc o s wi h he elec ic ield in he adia ion11. Hence, i causes mal unc ions o a o emen ioned de ices and i can also cause human heal h p oblems. The e o e, cu en ly esea che s a e highly engaged in c ea ing a new class o ma e ials called elec omagne ic in e e - ence (EMI) shielding ma e ials12. Fo good shielding e ec i eness (SE) ma e ials ha e o possess high elec ical conduc i i y (EC). Pu e me als such as coppe , aluminum, s ainless s eel ha e an ou s anding conduc i i y, hus p ominen SE. Howe e , hey a e expensi e, wi h low lexibili y, high densi y, and end o easily co ode. Recen ly, nanopa icles become o g ea in e es in he iew o applica ion in EMI-shielding a ea. This is due o highe aspec a io, highe in e acial eac i i y, and unique chemical and physical p ope ies due o nanoscale sizes. Among o he s, 2D MXenes a e ecen ly disco e ed e y p omising amily o ino ganic nanopa icles. MXenes we e i s ob ained and desc ibed in 2011 a D exel Uni e si y, USA13,14. The i s a icle de o ed o MXene dis- co e y epo ed he p epa a ion o Ti3C2Tx om he Ti3AlC2 MAX phase p ecu so 13. MXenes consis o qui e hin (only a ew a oms) laye s o ansi ional me al ca bides, ni ides, and/o ca boni ides. The gene al o mula o MXenes is Mn+1XnTx, whe e M is an ea ly ansi ional me al (Sc, Y, Ti, Z , H , V, Nb, Ta, C , Mo, o W), X is ca bon and/o ni ogen, and n = 1–3. T ep esen s he su ace e mina ion g oups ha a e mos ly = O, -F, -OH, and x in Tx ep esen s he numbe o su ace unc ionali ies. MXenes ha e an imp essi e lis o p ope ies, such as a high Young’s modulus15, good he mal and elec ical conduc i i ies16,17, adjus able band gap18, UV-ligh abso bance19, good EMI-shielding p ope ies20, and la ge ene gy capaci ance21. Due o possessing a a ie y o p ope ies, MXenes a e p omising candida es o nume ous applica ions, and among o he s, hese nanopa icles could be used as ille s in polyme ic nanocomposi es22. Cu en ly, mo e han 40 di e en MXenes ha e been p epa ed and desc ibed, and o e 100 s able compounds ha e been heo e ically p edic ed23,24. MXenes possess ew p ope ies, which a e a o able o hei applica ion as EMI-shielding ba ie s. Fi s o all, hei laye ed s uc u e, as due o his, inciden wa es when en e ing he s uc u e "in e ac wi h he high elec on densi y o MXene, leading o an ohmic loss o EM wa es"25, and la e hey a e changed in o mul iple in insically e lec ed (abso bed) wa es, hus signi ican ly dec easing he numbe o ansmi ed wa es. Secondly, MXenes high EC also plays an impo an ole. I is ad an ageous in his applica ion ield as his means high numbe o ee elec ons and high-densi y elec onic cloud. The p esence o ee elec ons p o ides e lec ion o he inci- den elec omagne ic wa es. Addi ional p ope ies, which make MXenes p omising EMI-shielding ma e ial, a e la ge speci ic su ace a ea, which can be adjus ed h ough syn hesis condi ions, lowe densi y, compa ing o hea y me als, ul alow hickness. Ti3C2Tx MXene was i s in es iga ed o i s abso p ion pe o mance in 2016, compa ing i o ha o he co esponding MAX phase (Ti3AlC2). The esul s showed ha when a ma e ial hick- ness o 1.4mm was used a a illing a io o 50 w .%, he ex eme e lec ion loss o Ti3C2Tx was −17dB, which was much lowe han ha o he MAX phase26. The EMI shielding pa ame e s o MXenes can be enhanced when combined wi h polyme s, a ious ypes o ibe s, ca bon de i a i es, me als, me al–o ganic amewo ks and o he ma e ials, as desc ibed in published pape s27–29. In he wo k o Shazad e al.30 MXenes we e i s ly s udied in a composi e o hei EMI SE (shielding e ec i eness) p ope ies. They p epa ed Ti3C2Tx—sodium algina e samples and ecei ed 57dB o SE. Ano he excellen esul was ob ained by Liu e al.31, who ab ica ed lexible, hyd ophobic MXene oams, which e ealed ou s anding 70dB o EMI-shielding pe o mance. E en be e alues we e achie ed by Nguyen e al.32. In his wo k au ho s p epa ed hyb id composi es wi h in oduc- ing bo h MXenes nanopa icles and g aphene oam (GF) in o PDMS (poly(dime hylsiloxane)) polyme ma ix. The highes a e age EMI SE was achie ed wi h Fe3O4@Ti3C2Tx/GF/PDMS sample eaching 80dB in X-band, 77dB in Ka-band, 83.6dB a 8.7GHz and 78.9dB a 39.6GHz. This specimen con aining 11.5% o Fe3O4@ Ti3C2Tx wi h hickness 1mm showed also supe b 630 S/cm o conduc i i y. Sligh ly lowe esul s we e ob ained in he wo k o Song e al.33. He e we e p epa ed also hyb id composi e, howe e ins ead o g aphene was used honeycomb s uc u al educed g aphene oxide ( GH) and as a ma ix was used epoxy esin. Addi ion o only 1.2 w .% o GH and 3.3 w .% o MXenes led o ecei ing ~ 390 S/cm o elec ical conduc i i y and 55dB o shielding e ec i eness. In he nex wo k ab ica ed composi es a e close o hose men ioned in his wo k in he iewpoin o polyme ma ix. Jin e al.34 p epa ed lame- e a dan mul ilaye ed ilms wi h MXene ille and PVA (poly( inyl alcohol)). The 27-μm hick PVA/MXene ilm exhibi ed ema kable 716 S/cm o EC and ~ 44dB o EMI SE. Howe e , as much as 19.5 w .% o ille load was used in his specimen. A he same ime, composi e e ealed 23- old enhanced he mal conduc i i y, compa ing o nea PVA, wha is a p omising esul o u he applica ion as ilms o p e en ion o lame p opaga ion. In his wo k, a new ype o HAVOH-based polyme ic nanocomposi e was p epa ed by solu ion cas ing, mixing an aqueous solu ion o HAVOH wi h a ious amoun s o delamina ed 2D MXene in a wa e suspension. Mo eo e , nanocomposi es con aining a 1D ille , SWCNTs, we e p epa ed by he same me hod. The combi- na ion o 1D and 2D ille s is an in e es ing app oach o inno a i e polyme ic composi e c ea ion wi h high applica ion po en ial; he e o e, a hi d se ies o HAVOH composi es was p epa ed con aining a hyb id mix u e o MXenes and SWCNTs. P epa ed nanocomposi es we e cha ac e ized using a mul i echnique app oach. Scan- ning elec on mic oscopy (SEM) and ansmission elec on mic oscopy (TEM) we e used o cha ac e ize he mo phology and s uc u e o he ob ained nanocomposi es, b oadband dielec ic spec oscopy (BDS) was used 3 Vol.:(0123456789) Scien i ic Repo s | (2023) 13:19126 | h ps://doi.o g/10.1038/s41598-023-46083-2 www.na u e.com/scien i ic epo s/ o elec ical conduc i i y measu emen s. The applica ion po en ial was examined by EMI-shielding analysis o ob ain knowledge abou he composi e elec omagne ic beha io . Di e en ial scanning calo ime y (DSC) and he mog a ime ic analysis (TGA) we e pe o med o s udy he he mal decomposi ion beha io . The no el y o his wo k is in he p epa a ion o bina y HAVOH/MXenes and e na y HAVOH/SWCNTs/ MXenes composi es, hei complex s udy, which e ealed ema kable EMI-shielding pe o mance o hyb id composi es, wha is a p omising basis o applica ions in his ield. Me hods Mul ilaye ed, nondelamina ed MXenes Ti3C2Tx we e ecei ed as a wa e -based pas e om D exel Uni e si y (Philadelphia, Pennsyl ania, U.S.A.) wi h a concen a ion o 0.767g o MXenes pe 1g o MXene pas e. Highly amo phous poly( inyl alcohol) (HAVOH) powde (comme cialized unde he ade name G-polyme , g ade OKS-1089, Nippon Gohsei, Japan) was p o ided by Mi subishi Chemicals. Single-walled ca bon nano ubes (SWCNTs) (pu i y 80–93%) we e pu chased om Tuball™ (OCSiAl Eu ope S.a. .l., G and Duchy o Luxembou g). To ob ain a delamina ed single-laye ed MXene solu ion, MXene pas e was mixed wi h LiCl (1g o Ti3C2Tx:1g o LiCl) in 20ml o deionized (DI) wa e . The beake wi h he mix u e was placed in o a wa e ba h and placed on a magne ic s i e . I was le a 35°C and 150 pm o s i ing o e nigh . The nex day, i was cen i uged a 3500 pm un il he supe na an became black. In u he s eps, he cen i uga ion cycle ime was inc eased o 1h. When he supe na an u ned da k g een, i con ained delamina ed single-laye ed MXene shee s, so i was he s a o solu ion collec ion. When he solu ion s a ed o appea ligh -g een o anspa en , cen i uga ion was s opped. To ob ain he concen a ion o he p epa ed solu ion, using 20mL o he solu ion and Celga d®3501 memb ane, his po ion o he solu ion was il e ed wi h acuum-assis ed il a ion (VAF), ob aining almos d ied MXene powde as a ilm (Fig.1). To emo e esidual wa e , he memb ane wi h MXene ilm was pu in o a acuum o en o d ying a 45°C un il he nex day. As a nex s ep, he concen a ion o MXenes in he p epa ed single-laye solu ion was calcula ed. Concen a ions we e usually in he ange o 0.1–0.5mg/ml; he e o e, he econcen a ion p ocess wi h a o a y acuum e apo a o was pe o med o inc ease he concen a ion. All composi es we e p epa ed wi h sol en cas ing using wa e as a sol en . Table1 summa izes he p esen ed composi ions and sho names o he ab ica ed HAVOH-based polyme ic nanocomposi es, and Fig.2 schema i- cally shows he p epa a ion p ocesses. To p epa e HAVOH/SWCNTs composi e samples i s , HAVOH powde was added o deionized (DI) wa e . Solu ions con aining 3.0 w .% o polyme we e p epa ed using a magne ic s i e o 30min a 50°C, hen he Figu e1. F ee-s anding ilm o MXenes p epa ed by VAF on a Celga d memb ane (Ø = 4cm, h = 18μm). Table 1. Composi ion o HAVOH-based specimens. HAVOH (H), w .% SWCNTs, w .% MXenes (MX), w .% Sho name 100 – – H 99.0 1.0 – H/1 SWCNTs 97.0 3.0 – H/3 SWCNTs 98.6 – 1.0 H/1 MX 97.0 – 3.0 H/3 MX 96.0 3.0 1.0 H/3 SWCNTs/1 MX 95.0 3.0 2.0 H/3 SWCNTs/2 MX 94.0 3.0 3.0 H/3 SWCNTs/3 MX 4 Vol:.(1234567890) Scien i ic Repo s | (2023) 13:19126 | h ps://doi.o g/10.1038/s41598-023-46083-2 www.na u e.com/scien i ic epo s/ empe a u e was inc eased o 90°C and le o u he s i ing o 30min. Depending on he concen a ion o he ille in he sample, a calcula ed amoun o SWCNTs was added o DI wa e and sonica ed wi h an ul asonic p obe o 1h (100% ampli ude, cycle—1). Then, he mix u e was added o HAVOH and le o mixing unde con inuous s i ing o 30min. In he nex s ep, he HAVOH/SWCNTs mix u e was mixed a 1200 pm o an addi ional 3h using a mechanical s i e . A e wa d, he mix u e was pou ed ou in o a poly e a luo oe hylene (PTFE) Pe i dish and d ied a 60°C unde acuum o o al wa e e apo a ion, which ook 5days. This ilm was cu in o small pieces o u he p ocessing wi h comp ession molding. Fo p epa a ion o HAVOH/MXenes composi e samples he HAVOH dispe sion p epa a ion p ocedu e was he same as desc ibed abo e. Acco ding o he desi ed ille load, a calcula ed amoun o MXene solu ion was added o dissol ed HAVOH and le o mixing o 30min. In he nex s ep, he beake con aining he HAVOH/ MXene mix u e was mechanically s i ed a 1200 pm o 3h. Then, he mix u e was pou ed ou in o a PTFE Pe i dish d ied a 60°C unde acuum o 5days o o al wa e e apo a ion, and he ob ained ilm was cu o comp ession molding. To ob ain HAVOH/SWCNTs/MXenes hyb id composi es, he p epa a ion p ocedu es desc ibed abo e we e combined. Fi s , HAVOH was dissol ed in wa e , and hen SWCNTs and MXene suspensions we e added and mixed on a magne ic s i e . A e wa d, he mix u e was mechanically s i ed a 1200 pm o 3h, pou ed in o PTFE Pe i dishes and p ocessed as desc ibed abo e. Ci cles o 0.3mm hickness and 2.5cm in diame e we e p epa ed by comp ession molding o he p epa ed composi es using a labo a o y hyd aulic p ess SRA 100 (Fon ijne, Ne he lands) a 2.4MPa and a 220°C o 10min. X- ay pho oelec on spec oscopy (XPS) signals we e eco ded using a The mo Scien i ic NEXSA G2 Su ace Analysis Sys em (The mo Fishe Scien i ic, UK) equipped wi h a mic o ocused, monoch oma ic Al Kα X- ay sou ce (1486.68eV). An X- ay beam o 400µm size was used. Spec a we e acqui ed in he cons an analyze ene gy mode wi h a pass ene gy o 200eV o he su ey. Na ow egions we e collec ed using a pass ene gy o 50eV. Cha ge compensa ion was achie ed wi h he sys em dual beam lood gun. The mo Scien i ic A an age so wa e, e sion 6.6.0 (The mo Fishe Scien i ic, UK), was used o digi al acquisi ion and da a p ocessing. Spec al calib a ion was de e mined by using he au oma ed calib a ion ou ine and he in e nal Au, Ag and Cu s anda ds supplied wi h he K-Alpha sys em. Su ace composi ions (in a omic %) we e de e mined by conside - ing he in eg a ed peak a eas o he de ec ed a oms and he espec i e sensi i i y ac o s. The mo phology o he in es iga ed samples was obse ed by a JEOL 7600F Scho ky ield emission scanning elec on mic oscope (SEM FES) (Jeol L d., Tokyo, Japan). The nanocomposi es wi h HAVOH as he ma ix we e in es iga ed a an accele a ing ol age o 5kV in high acuum. Be o e SEM analysis, samples we e spu e ed wi h a hin laye o gold by a Balze s SCD 040coa e (Balze s Union Limi ed, Balze s, Liech ens ein). AzTec so wa e (Sp ing ield, NJ, USA) was used o collec igu es. Fo SEM, all samples we e ac u ed in liquid ni ogen, and a e wa d, hese c oss-sec ional a eas we e scanned. B igh - ield ansmission elec on mic oscopy (TEM) analysis was ca ied ou by means o a FEI Tecnai G12 Spi i Twin (LaB6 sou ce) equipped wi h a FEI Eagle 4k CCD came a. The accele a ing ol age was se a 120kV. Be o e analysis, ul a hin sec ions o nanocomposi e samples (nominal hickness 150nm) we e ob ained a oom empe a u e unde d y condi ions by using a Leica UC6 ul amic o ome and deposi ed on 400 mesh coppe g ids. B oadband dielec ic spec oscopy (BDS) measu emen s we e pe o med by a No ocon ol Concep 40 wi h an Alpha dielec ic spec ome e p o ided by No ocon ol Technologies GmbH (Ge many) in he equency Figu e2. Scheme o p epa a ion o h ee se ies o HAVOH polyme ic nanocomposi es. 5 Vol.:(0123456789) Scien i ic Repo s | (2023) 13:19126 | h ps://doi.o g/10.1038/s41598-023-46083-2 www.na u e.com/scien i ic epo s/ ange o 10–1Hz o 106Hz. A BDS 1200 (supplied by No ocon ol Technologies) pa allel-pla e capaci o wi h wo gold-pla ed elec odes was used as a es cell. AC pa ame e s we e measu ed a e acuum deposi ing gold elec odes (20mm in diame e ) on bo h sides o pelle ized samples o ensu e elec ical con ac . F equency scans we e conduc ed o each o he examined specimens. The diame e o he specimens was 40mm. Thickness anges we e be ween 0.2 and 0.5mm depending on he specimen. The sys em is ully au oma ed, and WinDe a so wa e was used o sys em con ol and da a acquisi ion. The EMI shielding e ec i eness o he p epa ed nanocomposi e shee s (leng h × wid h = 2.3 × 1cm, hick- ness—1mm) was s udied wi h a ec o ne wo k analyze (Agilen N5230A) a 8.2–12.4GHz equency ange ( he so-called X-band) using a wa eguide sample holde . The elec omagne ic in e e ence shielding e e s o he a enua ion o he ansmi ing elec omagne ic wa es by he shielding ma e ial. A high alue o elec omagne ic in e e ence (EMI) shielding e ec i eness (SE) means less ene gy ansmi ed h ough he shielding ma e ial. Fo comme cial applica ions, a shielding ma e ial which possesses he (SE) o 20dB can block 99% o he inciden elec omagne ic wa es. The elec omagne ic shielding e ec i eness (SE) can be exp essed as he a ion o ansmi ed powe co esponding o he inciden powe o he EM wa e, as: whe e, PT (ET o HT) and PI (EI o HI) symbolized ansmi ed powe and ini ial powe (elec ic and magne ic ield in ensi y) o EM wa e espec i ely. He e, SER and SEA a e he shielding e ec i eness because o e lec ion and abso p ion, espec i ely. SEM is he shielding e ec i eness due o mul iple e lec ions inside he ma e ial, which can be negligible when SET > 10dB. The o al shielding e iciency (SET) is gi en as Eq.(2): The shielding e ec i eness o he (magne ic/conduc i e) polyme composi e illed e.g. wi h g aphene oxide can be e alua ed on he basis o sca e ing pa ame e s (S11, S12, S21, S22) by ollowing Eqs.(3), (4): A wo-po ne wo k analyse can be u ilized o measu e he sca e ing pa ame e s (S11, S12, S21 and S22), which co ela es wi h e lec ion (R) and ansmission coe icien s (T): The ela ionship be ween e lec ed (R), abso bed (A), and ansmi ed (T) po ions o elec omagne ic wa e in ensi y ollows: Using his equa ion, di ec de e mina ion o R and T om measu ed alues o S11 and S21, espec i ely, enables one o ex ac abso bed pa (A) o elec omagne ic wa e in ensi y11. The mal cha ac e iza ion was pe o med using a di e en ial scanning calo ime e (DSC-Q1000, TA, USA) in a lowing ni ogen a mosphe e wi h a gas low a e o 50mL/min. Samples we e p elimina ily hea ed om 0 o 220°C wi h a hea ing a e o 10°C/min o e ase hei he mal his o y. Then, a e an iso he m a 220°C o 5min, a cooling scan un il 0°C a 10°C/min and a second hea ing scan om 0 o 220°C a a a e o 10°C/min we e pe o med. The mal pa ame e s (glass ansi ion empe a u e Tg, mel ing empe a u e Tm, and mel ing en halpy ΔHm) on he second hea ing scan we e calcula ed. The mog a ime ic analysis (TGA) measu emen s we e ca ied ou on a TGA Q500 he mog a ime ic analyze (TA Ins umen s, USA). Fo he ac ual analysis, a small amoun o sample (on he o de o ens o mg) was p epa ed and ans e ed in o a pla inum pan. Measu emen s we e ca ied ou a a hea ing a e o 10°C/ min om labo a o y empe a u e o 900°C in an ai a mosphe e. Consen o pa icipa e All au ho s con ibu ed o he esea ch p esen ed in he pape and app o ed hei pa icipa ion. Resul s and discussion Highly amo phous poly( inyl alcohol) is a biodeg adable polyme based on poly( inyl alcohol) modi ied wi h diol monome s (Fig.3), which is also wa e soluble. The e a e only a ew wa e -soluble polyme s. This p ope y was a o able o ou wo k on he ab ica ion o HAVOH-based composi es wi h MXenes because MXenes we e ecei ed as a wa e -based pas e, and hei u he p ocessing, e.g., delamina ion, was also pe o med in wa e . In his s udy, we wo ked wi h nonoxidized MXene pas e, which is desc ibed in de ail he e (labelled “MX2” in (1) SE (dB)=SER+SEA+SEM=10log  PT PI =20log  ET EI =20log  HT HI, (2) SET(dB)=SER+SEA. (3) SE R=10log10 1 1−R =10log10 1 1−|S11| 2  (4) SE A=10log10  1−R T =10log10  1−|S11| 2 |S21| 2 . (5) T=|S12|2=|S21|2 (6) R=|S11|2=|S22|2. (7) R2+A2+T2=1 6 Vol:.(1234567890) Scien i ic Repo s | (2023) 13:19126 | h ps://doi.o g/10.1038/s41598-023-46083-2 www.na u e.com/scien i ic epo s/ Re .35). Delamina ed MXene showed no oxida ion (only 2.9 a .% o Ti4+ signal ca. 458.5eV) and was e y clean wi h a low amoun o sp3 ca bon o 6.1 a .% (Fig.S1, TableS1). Only a small amoun o aluminum emained om he MAX phase in he s uc u e (TableS1). The hyd ophilic cha ac e o his ype o MXene was discussed and p o en in Re .36. Thus, i was no necessa y o ans e hese 2D ille s om wa e o ano he sol en , which could cause addi ional di icul ies, such as lowe yield due o losses du ing he ans e p ocess, agglome a ion and sedimen a ion. As a 1D nano ille , single-walled ca bon nano ubes (SWCNTs) we e used. The main eason is ha SWCNTs ha e highe elec ical conduc i i y han MWCNTs37,38. SWCNTs a e hyd ophobic, which is also e iden om he su ace composi ion de e mined by XPS, whe e app oxima ely 80.9 a .% sp2 ca bon is on he su ace and only app oxima ely 1.7 a .% oxygen p o ides hyd ophilic cha ac e (see Fig.S2 and TableS2). The e o e, i was challenging o p epa e homogeneous composi es. We p epa ed and cha ac e ized bina y and e na y composi es wi h he HAVOH ma ix and 1D SWCNTs and 2D MXenes as ille s (Table1). S udy o he mo phology and in insic s uc u e a e e y impo an cha ac e is ics o u he in e p e a ion o he ma e ial p ope ies. The o ien a ion o he ille s, hei dispe sion, p esence o agglome a es, inco po a ion in o he polyme ma ix, in e ac ion be ween he ma ix and he ille wi h o he ille s o addi ional helping componen s, e.g., copolyme s, su ac an s, compa ibilize s, e c., a ec he p ope ies o he inal ma e ial. Poo dispe sion o ille s, he p esence o agglome a es, and incomple ely e apo a ed sol en esidues can wo sen he elec ical and mechanical p ope ies o polyme ic nanocomposi es. S udy o he mo phology and s uc u e o HAVOH-based composi e samples was pe o med wi h SEM and TEM. In Fig.4, SEM mic og aphs o he pu e HAVOH ma ix (Fig.4a), bina y composi es HAVOH/1.0 w .% MXenes (Fig.4b), HAVOH/3.0 w .% SWCNTs (Fig.4c), and he e na y hyb id HAVOH/3.0 w .% SWCNTs/1.0 w .% MXenes (Fig.4d) a e p esen ed. All composi es e eal a homogeneous mo phology. When 2D MXene nano ille was added o HAVOH, he o ma ion o lamella ille s uc u es pa allel o he sample su ace was obse ed. This can be a ibu ed o he MXene laye ed s uc u e. Fo he bina y HAVOH/3.0 w .% SWCNTs (H/3 SWCNTs) sample (Fig.4c), ins ead o o de ed lamella s uc u es, well dispe sed SWCNTs wi hou la ge agglome a es a e obse ed. As a esul o mixing o 1D and 2D nano ille s, such as o he sample HAVOH/3.0 w .% SWCNTs/1.0w .% MXenes (H/3 SWCNTs/1 MX) (Fig.4d), a combina ion o indi idual s uc u es o bina y composi es wi h u ilized ille s is obse ed. In pa - icula , ei he lamella s uc u es ypical o MXenes o well-dispe sed SWCNTs ha a e able o connec MXene lamellae a e obse ed. Thus, imp o ing he elec ical conduc i i y o he samples by he c ea ion o con inuous conduc i e pa hways is p esen . Fu he insigh s in o he dispe sion and o ien a ion o he ille wi hin he HAVOH ma ix we e p o ided wi h TEM analysis. TEM mic og aphs o he bina y and e na y composi es a e shown in Fig.5 and addi ional pho os can be ound in SI (Fig.S3). Figu e5a shows a b igh - ield TEM mic og aph o H/3 MX composi e sample wi h 3.0 w .% o 2D MXenes, wi h a well-demons a ed laye ed s uc u e a ibu ed o he alignmen o MXene lamellae o he su ace o he ilm, con i ming wha was al eady e idenced by SEM analysis. MXene lamellae a e igh ly packed wi h each o he wi h egula mo phology. Fo he HAVOH/3.0 w .% SWCNTs bina y composi e (Fig.5b), CNT bundles can be clea ly obse ed. They ha e a loose s uc u e, which is e idenced in he mic og aph as g ay/black halos, because single nano ubes can- no be esol ed due o hei e y low diame e . When he wo ille s we e combined oge he , a con inuous ne o hyb id MXenes/SWCNTs was obse ed (Fig.5c). SWCNTs, in his case also e idenced as low-con as bundles in compa ison o high-a omic-numbe MXenes, con ibu e o he connec ion o he MXene lamellae, which clea ly indica es he o ma ion o 3D hyb id conduc i e pa hways wi hin he nanocomposi e s uc u e ha a e esponsible o he imp o ed elec ical conduc i i y. Fo his sample, he highly egula spa ial a angemen o MXene lamellae e idenced o he bina y HAVOH/MXene composi e is pa ially los as he a angemen o he lamellae is pe u bed and hinde ed by he cop esence o SWCNTs. HAVOH-based samples we e analyzed wi h BDS o s udy hei elec ical p ope ies. Figu e6 shows a plo o he measu ed conduc i i ies o he bina y and e na y HAVOH composi es. The nea ma ix wi h a σDC ′ conduc i i y alue o 6 × 10–12 S/cm had a ypical insula o esponse. Fo he composi e wi h 2.0 w . % MX, he conduc i i y inc eased o app oxima ely 2 × 10–9 S/cm; beyond a c i ical equency ( c), a powe law ollowed, whe eas o < c, σ′ exhibi ed a pla eau, co esponding o DC conduc i i y ( σDC ′ )39. The addi ion o 2.0w .% MXenes o HAVOH sligh ly inc eases σDC ′ conduc i i y, eaching 2 × 10–9 S/cm, while he composi e sample Figu e3. Chemical s uc u e o (a) PVOH and (b) HAVOH. 7 Vol.:(0123456789) Scien i ic Repo s | (2023) 13:19126 | h ps://doi.o g/10.1038/s41598-023-46083-2 www.na u e.com/scien i ic epo s/ wi h 1.0w .% o his ille has a simila cu e shape (simila c) and e y close alues o he nea ma ix. The specimen wi h 1.0 w .% o SWCNTs is on he same o de ange wi h a conduc i i y o 7.5 × 10–7 S/cm. Hyb id e na y composi es, HAVOH/3.0 w .% SWCNTs/1.0 w .% MXenes and HAVOH/3.0 w .% SWCNTs/2.0 w .% MXenes, oge he wi h bina y composi e HAVOH/3.0w .% SWCNTs in be ween, a e eaching mo e han wo imes be e conduc i i y compa ed o he HAVOH ma ix alone. Thei σDC ′ conduc i i y alues, 5.2 × 10–5, 6.1 × 10–5 and 7.9 × 10–5 S/cm, espec i ely, a e he highes among all ab ica ed HAVOH samples. The pe cola ion h eshold o HAVOH bina y composi es was calcula ed using he equa ion and scaling law: whe e σDC is he DC conduc i i y, pc is he pe cola ion h eshold, p is he olume ac ion o he ille , and is he exponen cha ac e izing he dimensionali y o he in es iga ed conduc i e sys em. In HAVOH/SWCNTs, pc is 0.7 ol.%, which co esponds o 1.0 w . %. Fo samples wi h MXenes ille , pc was 0.56 ol.%, which in weigh pe cen age is equal o 1.4 w .%. As shown in his plo , he elec ical conduc i i y o HAVOH-based composi es did no exceed 8 × 10–5 S/cm. This is jus one o de o magni ude om alues o 1.2×10-4 S/cm o HAVOH/6.0 w . % MWCNT p esen ed by San illo e al.5. So, wi h sligh ly lowe ille con en 4 (3 w .% SWCNTs + 1 w .% MX) and 5 (3 w .% SWCNTs + 2 w .% MX) w . % we achie ed a e y good conduc i e ne wo k pene a ed in o he HAVOH ma ix wi hou using any addi ional su ac an , as was he case o San illo e al5. The EMI shielding p ope ies o he nea HAVOH ma ix as well as o nanocomposi es wi h SWCNTs and MXene ille s in he equency ange om 8.2 o 12.4GHz (X-band) we e i s de e mined and exp essed by he S21 pa ame e . Acco ding o Fig.7, he HAVOH ma ix’s anspa ency in a gi en egion is app oxima ely 92%, i.e., i s shielding e iciency in a composi e wi hou nanopa icles is app oxima ely S21 = -0.45dB, which is negligible. Pa ame e S11 o all composi es indica es he high conduc i i y o he samples, and S11 app oaches ze o. The shielding e iciency S21 o composi es wi h 1.0 w .% SWCNTs exhibi inc easing shielding (−35dB), while he sample wi h 3 w .% o SWCNTs exhibi s wo se shielding, namely, −25dB. This is possibly caused by he poo quali y o he sample, which is mac oscopically i egula , wi h some holes and de ec s due o he high amoun o SWCNTs. Shielding o samples wi h 1.0 and 3.0 w .% o MXenes exhibi s good shielding (−10 and −15dB). Be - e esul s a e ob ained o samples con aining bo h ille s (SWCNTs and MXenes), which exhibi g ea shielding (8) σDC ≈  p−p c , Figu e4. SEM images o (a) nea H, (b) H/1 MX, (c) H/3 SWCNTs; and (d) H/3 SWCNTs/1 MX. 8 Vol:.(1234567890) Scien i ic Repo s | (2023) 13:19126 | h ps://doi.o g/10.1038/s41598-023-46083-2 www.na u e.com/scien i ic epo s/ Figu e5. TEM images o (a) H/3 MX; (b) H/3 SWCNTs; and (c) H/3 SWCNTs/3 MX. Figu e6. Dependency o eal pa o HAVOH/SWCNTs, HAVOH/MXenes, and HAVOH/SWCNTs/MXenes composi e samples conduc i i ies on equency. 9 Vol.:(0123456789) Scien i ic Repo s | (2023) 13:19126 | h ps://doi.o g/10.1038/s41598-023-46083-2 www.na u e.com/scien i ic epo s/ o −40dB (HAVOH/3.0 w .% SWCNTs/1.0 w .% MXenes) and −55dB (HAVOH/3.0 w .% SWCNTs/3.0 w .% MXenes), which is much highe han he sample wi h 3.0 w .% SWCNTs. This con i ms ha MXenes help o o m a compac conduc i e ne wo k oge he wi h he SWCNTs and imp o e hei EMI-shielding. The mo phology s udy showed ha MXene has a lamella s uc u e and he well-dispe sed SWCNTs o med a con inuous conduc i e pa h be ween he lamellae. Thus, imp o ing he elec ical conduc i i y in composi es HAVOH/ SWCNTs/MXenes is p oo o ha . Ac ually, a ma e ial abso bs EM wa es and con e s hem in o hea , and his con e sion abili y is de e mined by he conduc ion loss and he pola iza ion loss. Pola iza ion loss has an impo an con ibu ion o he abso p ion o EM wa es. In ac , he de ec s o med du ing he e ching p o- cess as was in oduced by Peng He e al.40 lead o he asymme y in he spa ial dis ibu ion o elec ons o o m dipole momen s. Mo eo e , e minal a oms a ached on he su ace o MXenes (Fig.S1) lead o he asymme ic dis ibu ion o cha ge densi y, which in- u n causes he o ma ion o dipoles. Unde an al e na ing elec omag- ne ic ield, hese dipoles will b eak loose and o a e di ec ionally. When hei o a ion canno keep up wi h he change in EM ield, pola iza ion elaxa ion occu s wi h EM ene gy loss. Recen esea che s ha e mainly ocused on he EMI shielding pe o mance o Ti3C2Tx MXene ilms31. Howe e , EM wa es a e mos ly e lec ed by high conduc i i y in he Ti3C2Tx ilm and his beha io is he same as a me al shielding he EM wa e. Only a small amoun o EM wa es can en e he body o ilms and be abso bed. Compa ed wi h he MXene ilms ha mainly use high conduc i i y o e lec EM wa es, he composi es made by dispe sing he SWCNTs and MXene in o he HAVOH ma ix can educe he conduc i i y and abso b mo e EM wa es by pola iza ion loss. This means ha mo e EM wa es can be a enua ed so ha seconda y e lec ions will be e ec i ely educed, demons a ing hei en i onmen ally iendly pe o mance. Figu e8 shows he spli o o al shielding in o abso p ion and e lec ion pa s and p o ides ano he iew o he shielding e iciency o HAVOH/SWCNTs/MXene mo phologies. The e lec i i y o all composi es is qui e simila , wi h alues in he ange o 7–15dB. Mo e in e es ing is he abso p ion o he samples, which show la ge di e ences among he samples. The samples illed wi h MXenes abso b much less han he samples illed wi h SWCNTs, which abso b up o 45dB. The con ibu ion o e lec ion and abso p ion can also be iewed in Table3 and Fig.S4. Visualizing he p opo ion be ween he h ee componen s in “RAT analysis” (analysis o e lec ion, abso p ion, and ansmission capabili y o each sample) clea ly indica es highe abso p ion pe cen age o samples wi h MXene/SWCNTs hyb id s uc u e. The esul s ob ained in his wo k we e compa ed wi h o he epo ed alues o he shielding e ec i eness o MXene composi es. Miao e al.41 ob ained 54.7dB o RLmin (ex eme e lec ion loss) o he MoS2/TiO2/Ti2CTx sample. This alue is he closes o ha epo ed he e; howe e , he sample hickness is h ee imes highe han ou HAVOH/3.0 w .% SWCNTs/3.0 w .% MXenes. Addi ionally, he ille a io ha has o be used is high, each- ing 70 w .%, which is almos 12 imes mo e han o ou specimen wi h a o al ille load o 6 w .%. Gao e al.42 also ecei ed high SE alues. P epa ed composi e wi h he moplas ic polyu e hane as a ma ix and MXenes ille showed 50.7dB, bu high amoun o ille load such as 28.6 w .% had o be admixed. HAVOH composi es showed g ea shielding e ec i eness. When compa ing he nea polyme ma ix and he composi e sample ha showed he bes esul s, namely, HAVOH/3.0 w .% SWCNTs/3.0 w .% MXenes, he di e ence is mo e han 100 imes. This indica es ha u iliza ion o bo h ille s in ela i ely small amoun s and a e y good syne gis ic e ec g ea ly inc eases e lec ion and abso p ion and dec eases ansmission o elec- omagne ic in e e ence, hus c ea ing a g ea ba ie . These esul s a e p omising o u he de elopmen o EMI-shielding ilms o de ices. To s udy he mal beha io o he specimens di e en ial scanning calo ime y and he mog a ime ic analy- ses we e used. DSC he mog ams o p is ine HAVOH and HAVOH-based composi e samples, eco ded du ing cooling om he mel and successi e hea ing o he mel -c ys allized samples, a e shown in Fig.6. Values o glass ansi ion empe a u es (Tg), mel ing empe a u es (Tm) and mel ing en halpy (ΔHm) a e summa ized in Table2. As shown, he DSC hea ing cu e o p is ine HAVOH, c ys allized om he mel a 10C/min, displays a Tg o 75.5°C, a Tm o 199.2°C and a ΔHm o 34.2J/g (Fig.9 and Table2). Fo bina y composi es con aining 8.0×10 9 9.0×10 9 1.0×10 10 1.1×10 10 1.2×10 10 1.3×10 10 -15.0 -13.5 -1.5 0.0 1.5 S 11 (dB) F equency (Hz) H/3 MX H/1 SWCNTs Nea HAVOH H/3 SWCNTs/1 MX H/3 SWCNTs/3 MX H/3 SWCNTs H/1 MX a) 8.0×10 9 9.0×10 9 1.0×10 10 1.1×10 10 1.2×10 10 1.3×10 10 -60 -50 -40 -30 -20 -10 0 S 21 (dB) F equency (Hz) Nea HAVOH H/1 MX H/1 SWCNTs H/3 SWCNTs/3 MX H/3 SWCNTs/1 MX H/3 SWCNTs H/3 MX b) Figu e7. EMI-shielding e iciency exp essed (a) by S11 pa ame e o he samples, and (b) by S21 pa ame e o he samples.