926:, was developed for mapping three-dimensional topographical variations in atomic surfaces with high resolution (on the order of fraction of nanometers). AFM was developed to overcome the material conduction limitations of electron transmission and scanning microscopy methods (SEM & STM). Invented by Binnig, Quate, and Gerbe in 1985, atomic force microscopy uses laser beam deflection to measure the variations in atomic surfaces. The method does not rely on the variation in electron conduction through the material, as the
697:
commercial scale, the grafting technique is referred to as photoinitiated lamination, where desired surfaces are joined by grafting a polymeric adhesion network between the two films. The low adhesion and absorption of polyolefins, polyesters, and polyamides is improved by UV-irradiation of an initiator and monomer transferred through the vapor phase to the substrate. Functionalization of porous surfaces have seen great success with high temperature photografting techniques.
1048:
the coating rheology. Dispersing aids often involve steric or electrostatic repulsion of the polymer particles, providing colloidal stability. The dispersing aids adsorb (as in a grafting onto scheme) onto latex particles giving them functionality. The association of other additives, such as thickeners shown in the schematic to the right, with adsorbed polymer material give rise to complex rheological behavior and excellent control over a coating's flow properties.
910:(EDS/EDX) are composition characterization techniques that use x-ray excitation of electrons to discrete energy levels to quantify chemical composition. These techniques provide characterization at surface depths of 1–10 nanometers, approximately the range of oxidation in plasma and corona treatments. In addition, these processes offer the benefit of characterizing microscopic variations in surface composition.
715:
microscopy or spectroscopy, often expensive and demanding tools. Contact angle measurement (goniometry) can be used to find the surface energy of the treated and non-treated surface. Young's relation can be used to find surface energy assuming the simplification of experimental conditions to a three phase equilibrium (i.e. liquid drop applied to flat rigid solid surface in a controlled atmosphere), yielding
24:
289:
335:
obstacles with plasma processing preclude it from being a competitive surface modification method within industry. The process begins with production of plasma via ionization either by deposition on monomer mixtures or gaseous carrier ions. The power required to produce the necessary plasma flux can be derived from the active volume mass/energy balance:
1040:
192:, refers to the addition of polymer chains onto a surface. In the so-called 'grafting onto' mechanism, a polymer chain adsorbs onto a surface out of solution. In the more extensive 'grafting from' mechanism, a polymer chain is initiated and propagated at the surface. Because pre-polymerized chains used in the 'grafting onto' method have a
696:
The modification of inert surfaces of polyolefins, polyesters, and polyamides by grafting functional vinyl monomers has been used to increase hydrophobicity, dye absorption, and polymer adhesion. This photografting method is generally used during continuous filament or thin film processing. On a bulk
678:
Thermoplastic polyethylene and polypropylene treated with brief oxygen plasma exposure have seen contact angles as low as 22°, and the resulting surface modification can last years with proper packaging. Flame plasma treatment has become increasingly popular with intravascular devices such as balloon
323:
allows treatment at an optimized location. Conversely, in-line corona treatments have been implemented into full-scale production lines such as those in the newspaper industry. These in-line solutions are developed to counteract the decrease in wetting characteristics caused by excessive solvent use.
318:
Commercially, corona treatment has been used widely for improved dye adhesion before printing text and images on plastic packaging materials. The hazardous nature of remnant ozone after corona treatment stipulates careful filtration and ventilation during processing, restricting its implementation to
957:
The modification of surfaces to keep polymers biologically inert has found wide uses in biomedical applications such as cardiovascular stents and in many skeletal prostheses. Functionalizing polymer surfaces can inhibit protein adsorption, which may otherwise initiate cellular interrogation upon the
322:
Several factors influence the efficiency of the flame treatment such as air-to-gas ratio, thermal output, surface distance, and oxidation zone dwell time. Upon conception of the process, a corona treatment immediately followed film extrusions, but the development of careful transportation techniques
1047:
In water-borne coatings, an aqueous polymer dispersion creates a film on the substrate once the solvent has evaporated. Surface functionalization of the polymer particles is a key component of a coating formulation allowing control over such properties as dispersion, film formation temperature, and
700:
In microfluidic chips, functionalizing channels allows directed flow to preserve lamellar behavior between and within junctions. The adverse turbulent flow in microfluidic applications can compound component failure modes due to the increased level of channel interdependency and network complexity.
314:
of a material, often polymers and natural fibers. Most commonly, a thin polymer sheet is rolled through an array of high-voltage electrodes, using the plasma created to functionalize the surface. The limited penetration depth of such treatment provides vastly improved adhesion while preserving bulk
207:
The processes of grafting "onto", "from", and "through" are all different ways to alter the chemical reactivity of the surface they attach with. Grafting onto allows a preformed polymer, generally in a "mushroom regime", to adhere to the surface of either a droplet or bead in solution. Due to the
687:
Grafting copolymers to a surface can be envisioned as fixing polymeric chains to a structurally different polymer substrate with the intention of changing surface functionality while preserving bulk mechanical properties. The nature and degree of surface functionalization is determined by both the
933:
The application of AFM on polymeric surfaces is especially favorable because polymer general lack of crystallinity leads to large variations in surface topography. Surface functionalization techniques such as grafting, corona treatment, and plasma processing increase the surface roughness greatly
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is a controlled, rapid, cost-effective method of increasing surface energy and wettability of polyolefins and metallic components. This high-temperature plasma treatment uses ionized gaseous oxygen via jet flames across a surface to add polar functional groups while melting the surface molecules,
714:
In industrial corona and plasma processes, cost-efficient and rapid analytical methods are required for confirming adequate surface functionality on a given substrate. Measuring the surface energy is an indirect method for confirming the presence of surface functional groups without the need for
212:
this causes, the grafting density is lower for 'onto' in comparison to 'grafting from'. The surface of the bead is wetted by the polymer and the interaction in the solution caused the polymer to become more flexible. The 'extended conformation' of the polymer grafted, or polymerized, from the
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provides interfacial energies and injected monomer fragments larger than comparable processes. However, limited fluxes prevent high process rates. In addition, plasmas are thermodynamically unfavorable and therefore plasma-processed surfaces lack uniformity, consistency, and permanence. These
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A series of solutions with known surface tension (e.g., Dyne solutions) can be used to estimate the surface energy of the polymer substrate qualitatively by observing the wettability of each. These methods are applicable to macroscopic surface oxidation, as in industrial processing.
808:
493:
292:
An example reaction scheme for the cleavage of bonds in the polymer chains of a polyolefin surface. The presence of ozone, as the result of an ionizing electric arc produced by a Corona treater for example, leads to oxidation of the surface yielding polar
180:
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In the context of plasma processed polymer surfaces, oxidized surfaces will obviously show a greater oxygen content. Elemental analysis allows for quantitative data to be obtained and used in the analysis of process efficiency.
662:
Dissipation is generally initiated via direct current (DC), radio frequency (RF), or microwave power. Gas ionization efficiency can decrease the power efficiency more than tenfold depending on the carrier plasma and substrate.
221:. This results with a polymer that has favorable interactions with the solution, allowing the polymer to form more linearly. Grafting from therefore has a higher grafting density since there are more access to chain ends.
183:
The two methods of co-polymer grafting. Notice the difference in density of polymer chains, the equilibrium conformation of polymer molecules in solution gives the "mushroom" regime shown for the grafting-onto
720:
340:
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Adsorbed functionalities (e.g., surfact molecules) on a dispersed polymer particle interact with solvated associative thickeners (e.g., aqueous cellulosic polymer) yielding novel rheological behavior.
877:
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from a polymer bead surface. This grafting technique allows for excellent control over the peptide composition as the bonded chain can be washed without desorption from the polymer.
1031:
Narrow biocompatibility requirements within the medical industry have over the past ten years driven surface modification techniques to reach an unprecedented level of accuracy.
535:
891:
In the case of oxidizing treatments, spectra taken from treated surfaces will indicate the presence of functionalities in carbonyl and hydroxyl regions according to the
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570:
628:
599:
127:
allows for excellent control over the properties of a bulk polymer sample. However, surface interactions of polymer substrates are an essential area of study in
701:
In addition, the imprinted design of microfluidic channels can be reproduced for photografting the corresponding channels with a high degree of accuracy.
1138:
1107:
892:
123:
materials have widespread application due to their versatile characteristics, cost-effectiveness, and highly tailored production. The science of
1182:
1295:
Zeplin, Philip H. "Surface
Modification of Silicone Breast Implants by Binding the Antifibrotic Drug Halofuginone Reduces Capsular Fibrosis,"
907:
803:{\displaystyle {\boldsymbol {\gamma }}_{SG}={\boldsymbol {\gamma }}_{SL}+{\boldsymbol {\gamma }}_{LG}~{\cos {{\boldsymbol {\theta }}_{c}}}}
319:
applications with strict catalytic filtered systems. This limitation prevents widespread use within open-line manufacturing processes
41:
107:
488:{\displaystyle \textstyle \int \limits _{{V\!ol}_{I}}{k^{ion}}{n_{e}}{n_{0}}\,d{{V\!ol}_{I}}={\frac {n_{e}}{\tau _{n}}}{V\!ol_{I}}}
261:
processing, corona treatment, and flame treatment can all be classified as surface oxidation mechanisms. These methods all involve
903:
88:
60:
1233:
Rånby, Bengt (1998). "Photoinitiated modification of polmers: photocrosslinking, surface photografting and photolamination".
45:
140:
927:
67:
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favored conformation in solution (an equilibrium hydrodynamic volume), their adsorption density is self-limiting. The
1339:
851:
74:
817:
34:
923:
1196:"Rapid mold-free manufacturing of microfluidic devices with robust and spatially directed surface modifications"
200:
of the polymer therefore is the limiting factor in the number of polymer chains that can reach the surface and
56:
1183:
http://medicaldesign.com/contract-manufacturing/manufacturing-production/surface_treatments_wettability_0409/
242:
particles are often surface modified to control particle dispersion and thus coating characteristics such as
238:
Polymeric coatings are another area of applied grafting techniques. In the formulation of water-borne paint,
1085:
University of
Illinois at Urbana-Champaign. "New Polymer Coatings Prevent Corrosion, Even When Scratched."
1114:
232:
204:. The 'grafting from' technique circumvents this phenomenon and allows for greater grafting densities.
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1011:
1007:
262:
1062:
502:
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1215:
1194:
Pardon, G; Saharil, F; Karlsson, JM; Supekar, O; Carlborg, CF; Wijngaart, W; et al. (2014).
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197:
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applications. In these cases, the surface characteristics of the polymer and material, and the
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934:(compared to the unprocessed substrate surface) and are therefore accurately measured by AFM.
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synthesis can provide one example of a 'grafting from' synthetic process. In this process, an
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is a surface modification method using a low temperature corona discharge to increase the
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930:(STM) does, and therefore allow microscopy on nearly all materials, including polymers.
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catheters due to the precision and cost-effectiveness demanded in the medical industry.
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into the surface creates a higher surface energy allowing the substrate to be coated.
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951:
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993:
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denotes the surface energy of the solid–liquid, liquid–gas, or solid–gas interface
1307:
Meyer, Ulrich. Jörg
Handschel, Thomas Meyer, Jorg Handschel, Hans Peter Wiesmann.
179:
155:
is integral part of the formulation, manufacturing, and application of coatings.
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1025:
Photografting nanoelectromechanical structures to increase photopic sensitivity
954:) to functionalize the surface without compromising bulk mechanical properties.
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247:
144:
23:
1039:
171:, and even other polymers (grafting copolymers) onto the surface or interface.
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228:
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applications for example, the bodily response to foreign material, and thus
1246:
201:
168:
1282:
Balazs, D. J. "Surface
Modification of PVC Endotracheal Tube Surfaces,"
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is the ion loss by diffusion, convection, attachment, and recombination
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214:
136:
120:
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surfaces are often modified using light-activated mechanisms (such as
277:
163:
A polymeric material can be functionalized by the addition of small
1177:
Wolf, Rory. "Surface
Treatments for Wettability and Stickability,"
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Eisby, Jan. Frank Eisby. "Corona
Treatment, Why is it necessary?"
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between them largely determine its utility and reliability. In
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https://www.sciencedaily.com/releases/2008/12/081209125929.htm
17:
1309:
Fundamentals of Tissue
Engineering and Regenerative Medicine.
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implant, a predominant failure mode of medical prostheses.
265:
of polymer chains in the material and the incorporation of
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choice of copolymer and the type and extent of grafting.
344:
1164:
Schram, Daniel C. "Plamsa
Processing and Chemistry,"
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820:
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638:
609:
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Atmosphere- and pressure-dependent plasma processing
151:, is governed by surface interactions. In addition,
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Colloidal
Polymers: Synthesis and Characterization.
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Journal of the
American Society of Plastic Surgeons
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246:, film formation, and environmental stability (
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1272:http://www.nanoscience.com/education/afm.html
872:{\displaystyle {{\boldsymbol {\theta }}_{c}}}
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839:{\displaystyle {\boldsymbol {\gamma }}_{ij}}
208:larger volume of the coiled polymer and the
922:Atomic force microscopy (AFM), a type of
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108:Learn how and when to remove this message
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1311:Springer-Verlag, Berlin Heidelberg 2009
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970:Functionalization Method & Purpose
893:Infrared spectroscopy correlation table
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1137:: CS1 maint: archived copy as title (
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675:locking them into place upon cooling.
250:exposure and temperature variations).
217:must be in the solution and there for
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1155:Enercon Industries Corporation 1994.
908:Energy-dispersive X-ray spectroscopy
46:adding citations to reliable sources
1010:(PDMS) microfluidic patterning for
213:surface of the bead means that the
1089:, 10 Dec. 2008. Web. 6 Jun. 2011.
14:
1168:2002. Vol. 74, No. 3, pp. 369–380
1286:Vol. 6. Suppl. 1, 2003 (page 86)
1270:, NanoScience Instruments. 2011
904:X-ray photoelectron spectroscopy
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33:needs additional citations for
1200:Microfluidics and Nanofluidics
879:is the measured contact angle
231:chain is grown by a series of
1:
1153:Corona Treatment: An Overview
1019:Polymethylmethacrylate (PMMA)
996:to prevent capsular fibrosis
928:scanning tunneling microscope
705:Surface analytical techniques
530:{\displaystyle {{V\!ol}_{I}}}
1284:European Cells and Materials
298:Oxidizing polymeric surfaces
188:Grafting, in the context of
1324:Marcel Dekker 2003 New York
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710:Surface energy measurement
1212:10.1007/s10404-014-1351-9
1004:Synthetic vascular grafts
924:scanning force microscopy
652:{\displaystyle \tau _{n}}
667:Flamed plasma processing
630:is the electron density
1320:Elaissari, Abdelhamid.
1268:Atomic Force Microscopy
975:Polyvinylchloride (PVC)
918:Atomic force microscopy
601:is the neutral density
572:is the ionization rate
565:{\displaystyle k^{ion}}
315:mechanical properties.
276:. The incorporation of
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1012:selective adsorption
1008:Polydimethylsiloxane
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42:improve this article
1151:Markgraf, David A.
1063:Surface engineering
967:Medical Application
683:Grafting techniques
175:Grafting copolymers
57:"Polymeric surface"
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948:Biomaterial
899:XPS and EDS
284:Methodology
1124:2011-06-07
1074:References
906:(XPS) and
229:amino acid
145:biomedical
68:newspapers
1255:136547383
1068:Tribology
859:θ
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347:∫
254:Oxidation
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219:lyophilic
169:oligomers
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1052:See also
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271:hydroxyl
267:carbonyl
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165:moieties
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