Gamma irradiation-induced grafting of 2-hydroxyethyl methacrylate (HEMA) onto ePTFE for implant applications

Conformal Growth of Ultrathin Hydrophilic Coatings on Hydrophobic Surfaces Using Initiated Chemical Vapor Deposition

“…Hydrophilic polymer coatings on hydrophobic substrates have been studied for applications in anti-fogging and anti-frosting, − anti-fouling, self-cleaning, separations, improved adhesion, and biological implants . The properties for these applications come from the hydrophilic coatings, which are polymers, such as poly­(vinyl pyrrolidone), polymethacrylates, − and poly­(acrylic acid), and biological molecules, such as proteins .…”

“…The downsides to these methods that use solvents include damage to the underlying substrate, unwanted side reactions and byproducts, along with often requiring numerous steps to achieve the desired coating and properties. A dry, or solvent-free, method that has been successful in depositing hydrophilic polymers on hydrophobic substrates is plasma-enhanced chemical vapor deposition (PECVD). ,, PECVD works by using energy from the plasma to activate the monomer vapor, creating precursor species through which a plasma polymer forms on a solid substrate . PECVD, however, has drawbacks such as damage to the substrate from the harsh, high-energy plasma conditions and undesirable branching and crosslinking of the deposited polymers, which leads to a decrease in hydrophilicity and wettability that drives up the contact angle (where a water contact angle, WCA, <90° is generally defined as hydrophilic and >90° is hydrophobic).…”

“…PECVD, however, has drawbacks such as damage to the substrate from the harsh, high-energy plasma conditions and undesirable branching and crosslinking of the deposited polymers, which leads to a decrease in hydrophilicity and wettability that drives up the contact angle (where a water contact angle, WCA, <90° is generally defined as hydrophilic and >90° is hydrophobic). Previous studies have used plasma polymerization to specifically deposit poly­(2-hydroxyethyl methacrylate) (PHEMA) onto expanded polytetrafluoroethylene (ePTFE), where the resulting surfaces had poor surface adhesion and were only slightly hydrophilic at 79° WCA. , Another approach is to use plasma exposure to first render the substrate surface hydrophilic and then deposit by spin- or dip-coating a hydrophilic polymer over the plasma-treated substrate surface. However, this approach has similar challenges related to plasma treatment and liquid processing, where plasma surface modification often roughens and etches the substrate , and solution coating often suffers from the solvent being incompatible with the underlying substrate, leading to liquid dewetting even on plasma-treated, hydrophilized surfaces …”

“…Hydrophilic polymer coatings on hydrophobic substrates have been studied for applications in anti-fogging and antifrosting, 1−3 anti-fouling, 4 self-cleaning, 5 separations, 6 improved adhesion, 7 and biological implants. 8 The properties for these applications come from the hydrophilic coatings, which are polymers, such as poly(vinyl pyrrolidone), 9 polymethacrylates, 10−12 and poly(acrylic acid), 2 and biological molecules, such as proteins. 13 The substrates are common hydrophobic polymers such as poly(methyl methacrylate), 11 polypropylene, polystyrene, poly(vinyl chloride), nylon, 12 and polyethylene, 13,14 along with long-alkyl chain 15 and fluorinated 16 surfaces.…”

Magnetic Superporous Poly(2-hydroxyethyl methacrylate) Hydrogel Scaffolds for Bone Tissue Engineering

“…PHEMA-based materials have been widely used in contact and intraocular lenses, artificial cornea, vitreous humor replacement, artificial emboli, burn dressings, hemodialysis membranes, hemoperfusion packings, implants for soft tissue reconstructive surgery, reconstruction of vocal cord, etc. [ 11 , 12 , 13 , 14 ]. These applications were facilitated by suitable material properties, such as hydrophilicity (homogeneous PHEMA absorbs ~40% of water), swelling, biocompatibility, inertness, nondegradability, and tissue-like mechanical characteristics (softness) [ 15 ].…”