PLASMA POLYMERIZATION OF ACETYLENE/CO_2/H_2

A study has been made on the plasma polymerization of acetylene/CO_2/H_2 in a capacitively coupled RF plasma. The monomer mixture yielded a crosslinked film with light brown color. A kinetic study is reported for the plasma polymer ization of acetylene/CO_2/H_2. The effects of discharge power level and reactor geometry on the rate of polymer formation are reported. The structure of the plasma polymer is investigated by IR study.

PLASMA POLYMERIZATION OF HYDROPHILIC AND HYDROPHOBIC MONOMERS FOR SURFACE MODIFICATION OF NUCLE-MICROPOROUS MEMBRANE

Surface modification of nucle-microporous membrane by plasma polymerization of HEMA, NVP and D_4 has been studied. The hydrophilicity of membranes was increased with increasing of plasma polymerization time of hydrophilic monomers HEMA and NVP. The flow rate of water through the membrane was increased remarkably after plasma polymerization of HEMA on it.

IMPROVEMENT OF DISPERSION ABILITY OF NANOMETER PARTICLES BY MEANS OF PLASMA POLYMERIZATION

In order to find a new way to improve the dispersion ability of nanometer material, an investigation on preparation of thin film with low surface energy on the surface of nanometer material by means of plasma polymerization has been done. Some physical behaviors and chemical constitution of prepared film as well as the influence of polymerized film on nanometer material were tested. All the experimental results showed that this is a possible way to improve the dispersion ability of nanometer materials.

PLASMA POLYMERIZATION OF HEXAMETHYLCYCLOTRISILOXANE

In a capacitively coupled RF discharge system with external electrodes ,hexamethyicyclotrisiloxane was polymerized, and the effects of discharge power and plasma gas on polymer deposition rate were studied. The polymer structures and properties were studied by IR spectroscopy, XPS measurement, PGC/MS combined technique, TG analysis and contact angle measuring. The results showed that the polymers prepared in H_2 or O_2 have higher C/Si ratio in comparison with those prepared in inert gases. PGC/MS results revealed the existence of many short carbon chains in the polymer structure .TG analysis suggested that the polymers prepared in the inert gas would possess better thermal stabilities.

STUDIES ON THE PERMEABILITY OF P VC/EBBA OVERLAPPED ULTRATHIN COMPOSITE MEMBRANES MODIFIED BY PLASMA-POLYMERIZATION WITH FLUOROCARBON MONOMERS

The PVC/EBBA ultrathin composite membranes with thickness of about 100 nm were prepared by spreading the solution on water surface. The overlapped composite membrane showed a characteristic aggregation structure in which the polymer matrix exists as a three-dimensional spongy network and the liquid crystal domains werc observed. Tne surface modification for the overlapped membranes was carried out by means of plasma-polymerization with the monomers of fluorocarbon compounds. Both Arrhenius plots of permeability coefficients for oxygen ((?)_O_2) in the membrane samples before and after modification showed significant increase in the vicinity of the T_(KN) of EBBA.

A Novel Continuously Initiated Polymerization by One-Atmosphere Low Temperature Plasma Device

A novel atmospheric plasma device developed in this paper, which is more effective and convenient to study the plasma-initiated polymerization (PIP) than conventional setup. The structure and mechanism of the device is introduced. Some plasma-initiated polymerization experiments are carried out on the device, and the conversion of AA (Acrylic acid) and AM (Acryl amide) atmospheric (N2) plasma polymerization are respectively 89% and 94% after 120 h post polymerization, whereby IR spectra of the product (AA, AM). Our PIP result are confirmed.

Numerical Analysis of Plasma Initiated Polymerization

Plasma initiated polymerization is a kind of well-known radical polymerization mechanism, but it has the ＇living＇ polymerization feature and produces ultra-high molecular weight polymer. In order to explain such phenomena, we calculate the basic data of plasma initiated polymerization of methylmethacrylate （MMA） according to the principle of polymer physics and chemistry. It results in that the radical concentration ranges from 10^-12mol/L to 10^-16mol/L corresponding to the radical life in 10^4s to 10^8s, which means the radicals have a long lifetime. Moreover because of the long lifetime radicals it causes a unique feature rather than the common radical polymerization, and also shows no ＂living polymerization＂. It is noticed in experiments that there are two key factors playing important roles. One is the effective radical amount produced during the plasma discharging while the another is the diffusion factor.

Hepatocyte culture in a radial-flow bioreactor with plasma polypyrrole coated scaffolds

We have designed and evaluated a radial-flow bioreactor for three-dimensional liver carcinoma cell culture on a new porous coated scaffold.We designed a culture chamber where a radial flow of culture medi-um was continuously delivered through it.Once this system was established,flow was simulated using flow dy-namics software based on numeric methods to solve Navier-Stockes flow equations.Perfusion within cell culture scaffolds was simulated using a flow velocity of 7 mL/min and found that cell culture medium was distributed unhindered in the bioreactor chamber.Afterwards,the bioreactor was built according to the simulated design and was tested with liver carcinoma cells(HepG2)cultured over an L-polylactic acid scaffold whose surface was modified with iodine-doped polypyrrole.The bioreactor was tested under non-flow and in radial flow condi-tions.Cell density under radial flow conditions was almost double than that under static conditions and both total protein and albumin output was also increased under radial flow conditions.

Effect of synthesis variables of plasma synthesized polymers on growth of HepG2 cells

Low pressure plasma polymer films were synthesized using pyrrole and allylamine monomers and adding iodine was used(or not)for the reaction in both cases.They were polymerized on glass substrates under the same reaction conditions.Polymerization of allylamine was also studied at different operating powers.These thin polymer films were used as culture surfaces for HepG2 cells,a cell line derived from a human hepatoma.The proliferation,differentiation and two-dimensional propagation until obtaining monolayer of the cells was studied on the different synthetized films and correlations were established between the conditions of synthesis,the physicochemical characteristics obtained and the performance as substrates for the cellular growth.

Plasma graft of poly(ethylene glycol) methyl ether methacrylate (PEGMA) on RGP lens surface for reducing protein adsorption

Poly（ethylene glycol） methyl ether methacrylate（PEGMA） was grafted on fluorosilicone acrylate rigid gas permissible contact lens surface by means of argon plasma induced polymerization to improve surface hydrophilicity and reduce protein adsorption.The surface properties were characterized by contact angle measurement,x-ray photoelectron spectroscopy（XPS） and atomic force microscopy respectively.The surface protein adsorption was evaluated by lysozyme solution immersion and XPS analysis.The results indicated that a thin layer of PEGMA was successfully grafted.The surface hydrophilicity was bettered and surface free energy increased.The lysozyme adsorption on the lens surface was reduced greatly.

Effect of Oxygen on Surface Properties and Drug Release Behavior of Plasma Polymer of n-Butyl Methacrylate

The effects of oxygen on the chemical structure, morphology, hydrophilicity and drug release behavior of radio-frequency plasma poly n- butyl methacrylate （PPBMA） thin film were carded out for the first time. ATR-FTIR and XPS showed that oxygen had little influence on the chemical structure and composition of PPBMAs, which did not agree with the thought that the presence of oxygen gas would increase the oxidized carbon functionalities in the plasma polymer. SEM and static contact angle measurement indicated that in case of deposition with oxygen, the smoothness and hydrophilicity of PPBMA were dramatically improved. The drug release behavior showed that drug release from the PPBMA coating without oxygen was biphasic patterns, while from PPBMA coating with oxygen was Higuchi release. These results were helpful for the design and tailoring of the PPBMA polymer film and other of plasma polymers film, but could provide a new idea for the drug release controlled form.

From plasma to plasmonics:toward sustainable and clean water production through membranes

The increasing demand for potable water is never-ending.Freshwater resources are scarce and stress is accumulating on other alternatives.Therefore,new technologies and novel optimization methods are developed for the existing processes.Membrane-based processes are among the most efficient methods for water treatment.Yet,membranes suffer from severe operational problems,namely fouling and temperature polarization.These effects can harm the membrane’s permeability,permeate recovery,and lifetime.To mitigate such effects,membranes can be treated through two techniques:plasma treatment(a surface modification technique),and treatment through the use of plasmonic materials(surface and bulk modification).This article showcases plasma-and plasmonic-based treatments in the context of water desalination/purification.It aims to offer a comprehensive review of the current developments in membrane-based water treatment technologies along with suggested directions to enhance its overall efficiency through careful selection of material and system design.Moreover,basic guidelines and strategies are outlined on the different membrane modification techniques to evaluate its prerequisites.Besides,we discuss the challenges and future developments about these membrane modification methods.

PLASMA MODIFICATION OF POLYPROPYLENE SURFACES AND GRAFTING COPOLYMERIZATION OF STYRENE ONTO POLYPROPYLENE

The surface of polypropylene （iPP） is modified with glow discharge plasma of Ar, so that the modified surfaces of iPP films are obtained. The studies of scanning electron microscopy （SEM） show the surface etching pattern of iPP films. The chemical structures of iPP films are confirmed by X-ray photoelectron spectroscopy （XPS） and Fourier transform infrared （FTIR） spectroscopy. The wetting properties of modified surfaces of iPP films are characterized by contact angle, and the free energy of surfaces is calculated. The free radical of modification surfaces of iPP is measured by chemical method. The surfaces of iPP are achieved with Ar plasma treatment followed by grafting copolymerization with styrene （St） in St. The grafting polymer of St onto iPP is characterized by FTIR. The grafting rate is dependent on plasma exposure time and discharge voltage. The studies show that homopolymerization of St is undergone at the sane time during the graftingcopolymerization of St onto/PP.

Surface Modification of Polypropylene by Ethylene Plasma and Its Induced β-Form in Polypropylene

This study aims to investigate the chemical structure and morphology of plasmapolymers produced by deposition of ethylene on the surface of polypropylene. The deposition films（sediments） of ethylene plasma on the surface of polypropylene are nonuniform, and the characterization results indicate the existence of hydroxyl groups and aldehyde（or ketone） groups in the sediments. The sediment of ethylene plasma on the polypropylene surface could induce the growth of β-form crystals in the surface layer of polypropylene.

Plasma-polymerized pericyte patches improve healing of murine wounds through increased angiogenesis and reduced inflammation

Pericytes have the potential to be developed as a cell therapy for the treatment of wounds;however,the efficacy of any cell therapy relies on the successful delivery of intact and functioning cells.Here,the effect of delivering pericytes on wound repair was assessed alongside the development of a surface-functionalized pericyte patch.Plasma polymerization(PP)was used to functionalize the surface of silicone patches with heptylamine(HA)or acrylic acid(AA)monomers.Human pericytes were subsequently delivered to murine excisional wounds by intradermal injection or using the pericyte-laden patches and the comparative effects on wound healing,inflammation and revascularization determined.The AA surface provided the superior transfer of the cells to de-epidermized dermis.Excisional murine wounds treated either with pericytes injected directly into the wound or with the pericyte-laden AA patches showed improved healing with decreased neutrophil infiltration and reduced numbers of macrophages in the wounds.Pericyte delivery also enhanced angiogenesis through a mechanism independent of VEGF signalling.Pericytes,when delivered to wounds,improved healing responses by dampening inflammation and promoting angiogenesis.Delivery of pericytes using PP-AA-functionalized patches was equally as effective as direct injection of pericytes into wounds.Pericyte-functionalized dressings may therefore be a clinically relevant approach for the treatment of wounds.