Photo Initiated Chemical Vapour Deposition To Increase Polymer Hydrophobicity

Abstract

Apple growers face new challenges to produce organic apples and now many cover orchards with high-density polyethylene (HDPE) nets to exclude insects, rather than spraying insecticides. However, rainwater- associated wetness favours the development of apple scabs, Venturia inaequalis, whose lesions accumulate on the leaves and fruit causing unsightly spots. Treating the nets with a superhydrophobic coating should reduce the amount of water that passes through the net. Here we treat HDPE and polyethylene terephthalate using photo-initiated chemical vapour deposition (PICVD). We placed polymer samples in a quartz tube and passed a mixture of H2 and CO through it while a UVC lamp (254 nm) illuminated the surface. After the treatment, the contact angle between water droplets and the surface increased by an average of 20°. The contact angle of samples placed 70 cm from the entrance of the tube was higher than those at 45 cm and 20 cm. The PICVD-treated HDPE achieved a contact angle of 124°. Nets spray coated with a solvent-based commercial product achieved 180° but water ingress was, surprisingly, higher than that for nets with a lower contact angle.

Large-Scale Encapsulation of Magnetic Iron Oxide Nanoparticles via Syngas Photo-Initiated Chemical Vapor Deposition

“…Previously, our group studied the chemistry of syngas photo-initiated chemical vapor deposition (PICVD) on flat surfaces 40 , 41 , 52 and on particulates in a plug-flow configuration 42 , 53 – 55 . Herein, we adapt this process for use in a sub-pilot scale jet-assisted fluidized bed reactor (FB-PICVD) to coat large quantities of MIONPs (grams) in order to improve their dispersion and stability in non-polar (hydrophobic) media.…”

Surface engineering of wood substrates to impart barrier properties: a photochemical approach

“…Treatment parameters were based on previous PICVD work, in conditions known to yield hydrophobic (water repelling) conditions (Bérard et al 2016). These parameters include sample position, gas mixture precursor ratio, operating pressure, treatment duration and photo-initiator feed rate.…”

“…These parameters include sample position, gas mixture precursor ratio, operating pressure, treatment duration and photo-initiator feed rate. Sample position was set to 850 mm from the gas inlet for all experiments in this study because it is believed that the wettability can decrease as the distance between samples and the source of the treatment increases (Bérard et al 2016). The samples are firstly inserted horizontally into the reactor with one face exposed to UV light, as seen in Figure 1, item 3.…”

“…This low-cost process can be applied to several types of substrate and is flexible enough to be easily implemented in projects of larger scope, without the mechanical limitations imposed by heat treatments (Dorval Dion and Tavares 2013). Moreover, PICVD has demonstrated the ability to form a thin film with tuneable wettability on a wide variety of substrates, a potential indicator of desirable barrier properties (Dorval Dion et al 2014), (Farhanian et al 2014), (Bérard et al 2016), (Labonté et al 2016), (Farhanian et al 2017). The present investigation aims to determine if PICVD can be used as a finishing treatment for indoor and outdoor timber to be resistant to solar radiation, to repel water and prevent moisture absorption.…”

Effects of Methyl Branching on the Properties and Performance of Furandioate-Adipate Copolyesters of Bio-Based Secondary Diols

“… 15 For example, the surface of PLA must be modified to make it suitable for applications such as no mass loss droplet transport 15 , 16 or reduced water ingress in crop net protection. 17 However, these modification protocols can be laborious and require the use of various solvents and coagulants, while also being heavily influenced by the crystallinity of the PLA surface. 18 2,3-BDO is the simplest 2° alcohol-containing diol, though it regularly gives low-chain length polyesters when combined with aromatic diacids under transesterification conditions.…”