Contents lists available at ScienceDirect Surface & Coatings Technology journal homepage: www.elsevier.com/locate/surfcoat InducedorderinginpolyethyleneterephthalateflmsirradiatedwithArions withanenergyof70MeV M.V. Zdorovets a,b,c, ⁎ , A.L. Kozlovskiy a,b , F.E. Harrison a , A.Z. Tuleushev d a L.N. Gumilyov Eurasian National University, 010008 Astana, Kazakhstan b The Institute of Nuclear Physics, 050032 Almaty, Kazakhstan c Ural Federal University, Yekaterinburg 620075, Russia d Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia ARTICLEINFO Keywords: Latent tracks Polyethylene terephthalate Heavy ions Polymer flms Induced ordering ABSTRACT Thisworkpresentstheresultsofastudyofstructuralchangesinlatenttracksinapolymer flmirradiatedwith heavyAr 8+ ionswithfuxesof2×10 10 ,5×10 11 ions/cm 2 ,and1×10 12 ions/cm 2 .Samplesofpolyethylene terephthalate(PET)polymerflmswithamorphousandcrystallineparts,withinitialweight fractionsof57%and 43%respectively,wereused.Thestudyofchangesinstructuralcharacteristicswascarriedoutusingthemethod ofX-raydifraction analysis in the Bragg-Brentano 2π geometry with azimuthal steps of 10°, where the initial position was aligned with the direction of the texture. It was found that the amorphous part of the irradiated samplesshowstheformationofananisotropicφdifractionrefection,thatincreaseswithincreasingirradiation fux, due to induced crystallisation of the PET material in the amorphous zone along the direction of the flm texture. From measurements of the ratio of the intensities of two difraction peaks (−110) and (100) in the crystalline part, it was found that an increase in irradiation fuxcausesadecreaseinthedegreeof initial tex- turing.ThiscorrelatedbehaviouroftheamorphousandcrystallinepartsofPETcanbeexplainedbythetransfer of stresses from the amorphous to the crystalline zones by covalent bonds acting along the PET molecular backbone.Annealingofirradiatedsamplesleadstothedissipationofnewlyformedcoherentscatteringareasin the amorphous part and the partial restoration of peak intensity (100) in the crystalline part, indicating the elastic nature of deformation of the polymer structure. 1. Introduction Since the discovery of the selective etching of latent tracks formed bypassingheavyfssion fragmentsthroughpolymer flms, followedby UV-treatment in air and chemical etching [1], and the introduction of theuseofheavy-ionacceleratorsfortheformationofthelatenttracks [2,3] there has been a steady growth in the production and use of polymermembranes.Thisgrowthisduetotheirwideuseinanumber of industrial applications: such as flter elements, osmotic membranes, ion and gas separation, haemodialysis, etc. [4–6]. There is a growing body of research supporting both improvements to the production of trackmembranesandthedevelopmentofnewapplications:tworecent reviews [7,8] analysed about 250 scientifc papers. Technologies have now been developed for producing membranes with various pore geometries (e.g. cylindrical, cone-shaped, cigar- shaped, hourglass-shaped), each having diferent functional properties that allow them to be used in various applications and technical solutions [9–12]. One of the most promising potential applications of track membranes is in ion separation and micro- and nano-fltration technologies [13]. An advantage of etched track membranes is their highthroughput,butasdisadvantageisthattheyhavelowselectivityof separation,althoughthisimprovesastheporediameterdecreases.Asa consequence,inrecentyearstherehasbeenafocusonthepropertiesof latenttrackssincewithoutetchingitispossibletoproducehigh-density nanopores with sufciently high separation efciency [14]. In particular, the study by [15] showed that latent tracks in a polymerflmcanseparateionsinaqueoussolutionwithbothselectivity and throughput comparable to the performance of biomembranes. Theauthorsfoundthatasufciently long UV-treatment oftheion- irradiated flms is a key condition for the formation of high-perfor- mance nanopores without chemical etching. They also identifed the importanceofthedetailsofthestructureofthelatenttrack. ItisknownthatPETfbresandflmshaveahighlevelofmolecular orientation(texture)alongthedirectionoftheirproduction,andthere https://doi.org/10.1016/j.surfcoat.2020.125490 Received 30 January 2020; Received in revised form 13 February 2020; Accepted 18 February 2020 ⁎ Corresponding author at: The Institute of Nuclear Physics, 050032 Almaty, Kazakhstan. E-mail address: mzdorovets@inp.kz (M.V. Zdorovets). Surface & Coatings Technology 386 (2020) 125490 Available online 19 February 2020 0257-8972/ © 2020 Elsevier B.V. All rights reserved. T