Plasma-induced Graft Research Articles

Plasma-induced graft copolymerization of HEMA onto silicone rubber and TPX film improving rabbit corneal epithelial cell attachment and growth

A poly(2-hydroxyethyl methacrylate) (pHEMA)-grafted polymer film was prepared by plasma-induced graft copolymerization onto an elastic material, silicone rubber, and a plastic material, poly(4-methyl-1-pentene) (TPX). The control, Ar plasma-treated and pHEMA-grafted silicone rubber and TPX surfaces were characterized by ESCA, FTIR-ATR, SEM and contact angle techniques. ESCA verified the respective chemical shift of control and Ar plasma-treated films. The presence of the grafted pHEMA was also verified by ESCA. The introduction of pHEMA onto a hydrophobic support provided an adequate surface for rabbit corneal epithelium cell attachment and growth. Cell attachment and growth onto these surfaces were examined by light microscopy. Cell attachment onto the control and Ar plasma-treated surfaces was negligible, while improved attachment and growth of rabbit corneal epithelium cells was demonstrated on the pHEMA-grafted polymeric surface. At 72 h, the pHEMA-grafted silicone rubber surface attached and grew more cells as compared with those on a pHEMA-grafted TPX surface. The pHEMA-grafted silicone rubber surface demonstrated a confluent cell layer after 72 h.

The effect of plasma-induced graft copolymerization of PHEMA on silicone rubber towards improving corneal epithelial cells growth.

A PHEMA grafted polymer film was prepared by plasma induced graft copolymerization onto an elastic material, silicone rubber. The control, Ar plasma-treated, and PHEMA-grafted silicone rubber surfaces were characterized by ESCA, FTIR-ATR, and SEM techniques. ESCA verified the respective chemical shift of control and Ar plasma-treated films. The presence of the grafted PHEMA was also verified by ESCA. The amounts of grafted PHEMA did not monotonously increase with the plasma exposure conditions, but decreased after passing a maximum. The introduction of PHEMA onto a hydrophobic support provided an adequate surface for rabbit corneal epithelium cell attachment and growth. Cell attachment and growth onto these surfaces were examined by light microscopy. Cell attachment onto the control and Ar plasma-treated surface was negligible, while improved attachment and growth of rabbit corneal epithelium cells was demonstrated on the PHEMA-grafted polymer surface. The PHEMA-grafted silicone rubber surface demonstrated a confluent cell layer after 72 h.

Plasma-Induced Graft Polymerization onto Powders

The plasma-induced graft polymerization of the momomer mixture composed of methacrylic acid, ethyl acrylate, methyl methacrylate and 2-hydroxyethyl acrylate onto TiO 2 , quinacridone red and carbon black powders has been achieved for the first time

Preparation of lubricious medical tube device by plasma-induced graft polymerization.

A heat-contractile tube was plasma-treated and subsequently surface-grafted with a water-soluble monomer. The surface graft polymerization of the monomer was performed in the presence of a small amount of riboflavin with the photo-induction method which required neither degassing process nor heating. The grafted surface was found to become almost permanently very hydrophilic and slippery when brought into contact with water. The role of riboflavin on the graft polymerization in an aerated monomer solution was also discussed.

Preparation of a single bipolar membrane by plasma-induced graft polymerization

A new type of single bipolar membrane was produced by plasma-induced graft polymerization. Acrylic acid was grafted on one side of a porous polypropylene film as a cation-selective region, and N-(2-methacryloyloxyethyl)- N,N,N-trimethylammonium chloride (QDM) on the other as an anion-selective region. The interface between the two regions consists of a porous structure retaining the original porous polypropylene framework. The rectification phenomenon, which is characteristic of the bipolar membrane, was observed for electric current and voltage between two membrane surfaces. As the membrane has the advantages of comparatively simple production, both in the laboratory and in industry, and the characteristic structure cited above, it should prove applicable to investigations on ion transport, as a biological model membrane in the field of biophysics, or to the production of chemical compounds as a novel membrane reactor in the field of biotechnology.

Enzyme immobilization in an asymmetric charged membrane

An entrapped enzyme asymmetric membrane was prepared by treatment of a porous polypropylene or polyethylene film by plasma-induced graft polymerization of acrylic acid on one side and N-(2-methacryloyloxyethyl)- N,N,N-trimethylammonium chloride on the other, followed by enzyme absorption through the pores of the film. Such a single membrane is called an immobilized-enzyme bipolar membrane. In this system, the reaction of urea by urease is studied. Using Donnan equilibrium and electroneutrality conditions for 1-2-valent ions, the permeation behavior of the system is interpreted. Although this model is unsuitable for use when a current is flowing, it provides insight into membrane design because it depends on structural parameters such as fixed charge density in the equations rather than on nonequilibrium thermodynamic theory. This type of membrane is applicable for use in reaction-separation systems as a compact membrane reactor.

Playing with the paraffines

Ar low-temperature plasma treatment and subsequent monomer grafting in vapor phase were employed to prepare hydrophobic nanofiltration (NF) membranes from polyacrylonitrile (PAN) ultrafiltration (UF) membranes. FTIR–ATR spectroscopy, XPS analysis and contact angle measurement were used to characterize the chemical and physical changes of PAN UF membranes modified by plasma-induced graft polymerization in vapor phase. It was revealed from FTIR spectra and XPS spectra that hydrophobic monomer, styrene, was successfully grafted onto PAN UF membrane surface. XPS analysis also indicated that the N/C atomic ratio decreases with increasing of grafting reaction time. But the O/C atomic ratios of the membranes grafted for less than 40 min are higher than that of virgin membrane. The enrichment of surface oxygen was observed, which might result from the formation of oxygen-containing groups after the residual active sites were exposed to air. The contact angle measurement results showed the grafted styrene groups caused a great increase in hydrophobicity of membrane surface grafted sufficiently. The filtration performances including permeation flux, J, and rejection, R, were determined with a mixture containing dewaxed oil (Mw ≈ 450 g/mol) and dewaxing solvent (toluene and methyl ethyl ketone) at 20 °C. The experimental results demonstrated the prepared hydrophobic NF membranes could reject the dewaxed oil up to 72.8%, which implies that these NF membranes can be used to recover the dewaxing solvent from the dewaxed lube oil filtrates.