Nanoscale Surface Lamellar Orientation and Lamellar Doubling in Ultrathin UHMW−PE Films

Abstract

Nanostructured, highly oriented, ultrathin ultrahigh-molecular weight polyethylene (UHMW-PE) films have been generated by melt drawing at temperatures in proximity to the mean polymer melting point (142.3 ( 0.2 °C, as determined by differential scanning calorimetry). In this temperature regime, the crystal nuclei size, the rheology, and the mobility of melted polymer chains strongly depend on the polymer temperature and therefore affect the development of the crystal morphology of the film. By stepwise increasing of the polymer processing temperature from 138 to 146 °C in steps of 2 °C, the mean lamellar thickness increases from 25 ( 2 to 32 ( 5 nm, as observed with tapping mode atomic force microscopy (AFM). Parallel with increasing thickness, the lamellae arrangement in the drawn films change from staggered to stacked and uncoordinated. On the basis of this observed surface crystal morphology, a model is proposed describing the temperature-dependent evolution of the lamellar arrangement in the melt drawn films. In sufficiently thin films, i.e., thickness of the order of a lamellar width (≈100 nm), discrete lamellae thickness values of 16 ( 2, 29 ( 2, and 62 ( 2 nm are observed in the UHMW-PE film drawn at a temperature of 140 °C, indicating the onset of lamellar doubling. For the first time, indications for a mechanical strain-induced lamellar doubling during film drawing are reported.

Evolutions, Revolutions and Trends in Biomaterials Science – A Perspective

“…By stepwise increasing of the polymer processing temperature the mean lamellar thickness increased from 25 ± 2 to 32 ± 5 nm, as observed with tapping mode AFM. [106] Parallel with increasing thickness, the lamellae arrangement in the drawn films changed from staggered to stacked and uncoordinated. For the first time, indications for a mechanical strain-induced lamellar doubling during film drawing have been reported.…”

“…Nanostructured surfaces of thermoplastic biomaterials may be produced in a great variety of desired surface patterns via a melt-drawing method for thin films for example of ultrahigh-molecular weight polyethylene (UHMW-PE). [106] Nanostructured, highly oriented, ultra-thin UHMW-PE films have been produced via melt drawing at temperatures near the mean polymer melting point. In this temperature regime, the crystal nuclei size, the rheology, and the mobility of melted polymer chains strongly depended on the polymer temperature and therefore affected the development of the crystal morphology of the film.…”

“…For the first time, indications for a mechanical strain-induced lamellar doubling during film drawing have been reported. [106] Acrylic acid films may be deposited by RF plasma assisted chemical vapour deposition. [107] One study dealt with the deposition of acrylic acid thin films by RF plasma assisted chemical vapour deposition.…”

Growth feature of PTFE coatings on rubber substrate by low-energy electron beam dispersion

“…It greatly improves the performance of rubber products in many applications, such as wettability, weather resistance, friction resistance, permeability, adhesion, and antistatic property. Recently, a variety of techniques are available to fabricate polymer coatings like electrochemical synthesis, [6] self-assembly, [7] sol-gel, [8] plasma polymerization, [9] pulsed laser ablation, [10] ion beam, [11] vacuum evaporation (thermal, electron beam) [1,12] , and sputtering technique. [13,14] Although many of the polymer coatings can be fabricated from solution methods, these films suffer easily from the contamination of residual solvent or impurities present in the solution.…”

Strain‐Induced Phase Morphology in Melt Drawn Ultrathin Highly Oriented Block Copolymer Films

“…Melt drawing is known to produce ultrathin, highly oriented films of semi-crystalline thermoplastic polymers [23] and has recently been applied to produce ultra high molecular weight polyethylene (UHMW-PE) films. [24] The melt drawing process is capable of orienting and aligning polymer chains. It generates crystal morphologies that to a large extent depend on the type of the polymer used.…”