Ososayensi bakhe ipulasitiki elilingana nensimbi — eqinile kodwa engasindi. Amapulasitiki, ososayensi bamakhemikhali abawabiza ngezinye izikhathi ngokuthi ama-polymer, ayisigaba sama-molecule amade akhiwe ngamayunithi amafushane aphindaphindayo abizwa ngokuthi ama-monomers. Ngokungafani nama-polymer angaphambilini anamandla afanayo, izinto ezintsha ziza kuphela ngesimo se-membrane. Futhi zingena umoya ngokuphindwe ka-50 kunepulasitiki engangenwa kakhulu emakethe. Esinye isici esiphawulekayo sale polymer ukulula kwayo kokwenziwa. Inqubo, eyenzeka ekushiseni kwegumbi, idinga izinto ezishibhile kuphela, futhi i-polymer ingakhiqizwa ngobuningi ngamashidi amakhulu anobukhulu obungama-nanometer kuphela. Abacwaningi babika okutholakele kwabo ngoFebhuwari 2 kumagazini i-Nature.
Izinto okukhulunywa ngazo zibizwa ngokuthi i-polyamide, inethiwekhi enezintambo zamayunithi e-amide molecular (ama-amide amaqembu amakhemikhali e-nitrogen anamathele kuma-athomu e-carbon ahlanganiswe nomoya-mpilo). Ama-polymer anjalo afaka i-Kevlar, i-fiber esetshenziselwa ukwenza ama-bulletproof vests, kanye ne-Nomex, indwangu engashi. Njenge-Kevlar, ama-molecule e-polyamide ezintweni ezintsha axhunyaniswe ngezibopho ze-hydrogen kulo lonke ubude bamaketanga awo, okuthuthukisa amandla aphelele ezinto.
“Zinamathelana njengeVelcro,” kusho umlobi oholayo uMichael Strano, unjiniyela wamakhemikhali we-MIT. Ukudabula izinto akudingi nje kuphela ukuphula amaketanga ama-molecule ngamanye, kodwa futhi nokunqoba izibopho ezinkulu ze-hydrogen eziphakathi kwama-molecule ezigcwele yonke inqwaba ye-polymer.
Ngaphezu kwalokho, ama-polymer amasha angakha ngokuzenzakalelayo ama-flakes. Lokhu kwenza izinto zibe lula ukuzicubungula, njengoba zingenziwa zibe amafilimu amancane noma zisetshenziswe njengesembozo sobuso befilimu encane. Ama-polymer endabuko avame ukukhula njengamaketanga aqondile, noma ahlukaniswe futhi axhumane ngokuphindaphindiwe ngobukhulu obuthathu, kungakhathaliseki ukuthi aqondiswa kanjani. Kodwa ama-polymer kaStrano akhula ngendlela eyingqayizivele ku-2D ukuze akhe ama-nanosheet.
“Ungakwazi yini ukuhlanganisa ephepheni? Ezimweni eziningi, awukwazi ukukwenza kuze kube yilapho umsebenzi wethu uqhubeka,” kusho uStrano. “Ngakho-ke, sithole indlela entsha.” Kulo msebenzi wakamuva, ithimba lakhe lanqoba isithiyo ukuze lenze lokhu kuhlanganiswa okunezinhlangothi ezimbili kwenzeke.
Isizathu sokuthi ama-polyaramides abe nesakhiwo esihleliwe ukuthi ukwenziwa kwe-polymer kuhilela indlela ebizwa ngokuthi i-autocatalytic templating: njengoba i-polymer ikhula futhi inamathela kumabhulokhi okwakha i-monomer, inethiwekhi ye-polymer ekhulayo ibangela ama-monomer alandelayo ukuthi ahlangane kuphela ngendlela efanele ukuqinisa ukuhlangana kwesakhiwo esinezilinganiso ezimbili. Abacwaningi babonise ukuthi bangayimboza kalula i-polymer ngesisombululo kuma-wafers ukuze benze ama-laminate anobubanzi obungamasentimitha angaphansi kwama-nanometer angu-4 ubukhulu. Lokho cishe kungaphezu kwesigidi sobukhulu bephepha elivamile lehhovisi.
Ukuze balinganise izakhiwo zemishini zezinto ze-polymer, abacwaningi balinganise amandla adingekayo ukubhoboza izimbobo ephepheni elilengisiwe ngenaliti encane. Le polyamide iqine ngempela kune-polymers yendabuko njenge-nylon, indwangu esetshenziselwa ukwenza ama-parachute. Ngokuphawulekayo, kuthatha amandla aphindwe kabili ukukhulula le polyamide enamandla kakhulu kunensimbi enobukhulu obufanayo. Ngokusho kukaStrano, into ingasetshenziswa njengesembozo sokuvikela ezindaweni zensimbi, njenge-veneers yemoto, noma njengesihlungi sokuhlanza amanzi. Emsebenzini wokugcina, i-membrane yesihlungi efanelekile idinga ukuba mncane kodwa iqine ngokwanele ukumelana nokucindezela okuphezulu ngaphandle kokuvuza ukungcola okuncane, okukhathazayo ekunikezeni kwethu kokugcina - okulingana kahle nale nto ye-polyamide.
Esikhathini esizayo, uStrano unethemba lokwandisa indlela yokwenza i-polymerization kuma-polymer ahlukene ngale kwale analog ye-Kevlar. “Ama-polymer asizungezile,” esho. “Enza konke.” Cabanga ngokuguqula izinhlobo eziningi ezahlukene zama-polymer, ngisho nalezo ezingavamile ezingahambisa ugesi noma ukukhanya, zibe amafilimu amancane angamboza izindawo ezahlukahlukene, uyanezela. “Ngenxa yale ndlela entsha, mhlawumbe ezinye izinhlobo zama-polymer manje zingasetshenziswa,” kusho uStano.
Ezweni elizungezwe yipulasitiki, umphakathi unesizathu sokujabula ngenye ipolymer entsha enezakhiwo zemishini ezingavamile neze, kusho uStrano. Le aramid ihlala isikhathi eside kakhulu, okusho ukuthi singashintsha ipulasitiki yansuku zonke, kusukela kupende kuya ezikhwameni kuya ekupakisheni ukudla, ngezinto ezimbalwa neziqinile. UStrano wanezela ukuthi ngokombono wokuzinza, le polymer enamandla kakhulu ye-2D iyisinyathelo esiqonde ngqo ekukhululeni umhlaba epulasitikini.
UShi En Kim (njengoba evame ukubizwa ngokuthi uKim) ungumbhali wesayensi ozimele ozalelwe eMalaysia kanye nomfundi oqeqeshwayo wokuhlela we-Popular Science Spring 2022. Ubhale kabanzi ngezihloko ezisukela ekusetshenzisweni okungavamile kolwembu—abantu noma izicabucabu ngokwazo—kuya kubaqoqi bakadoti emkhathini.
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Isikhathi sokuthunyelwe: Meyi-19-2022