Surface Topography Of Fibers Research Articles

Effects of high-intensity ultraviolet irradiation on the structure and mechanical properties of Sisal fibers

Abstract To explore the impact of high-intensity ultraviolet light on the structure and mechanical properties of sisal fibers, the article uses chemical methods in the sisal fiber surface silver-plated, untreated, and alkali-treated sisal fibers as a comparison, with the help of scanning electron microscopy, infrared spectroscopy on the fiber surface topography, the molecular structure of the research, determination of high-intensity ultraviolet irradiation under the mechanical tensile properties of the fiber. Exposure to high-intensity ultraviolet radiation for a brief period results in a reduction in the tensile strength, fracture elongation, and elastic modulus of untreated, alkali-treated, and chemically silver-plated sisal fibers by 95.2%, 77.7%, 55.9%, 92.8%, 76.9%, 42.1%, and 89.4%, 70.2%, 34.2%, respectively.

Multiscale analysis of hierarchical flax-epoxy biocomposites with nanostructured interphase by xyloglucan and cellulose nanocrystals

Natural biological systems feature hierarchical nanostructured architectures achieving high strength and toughness. In this work, the spontaneous adsorption of xyloglucan (XG) and cellulose nanocrystals (CNC) onto flax fabrics is considered to develop hierarchical interphases with improved interfacial adhesion in epoxy-based biocomposites. A multi-scale analysis is carried out, from the nano & micrometric scale with the characterization of fibre surface topography, work of adhesion and interfacial shear strength (IFSS) between flax fibres and epoxy resin, to the macroscopic scale with the transverse mechanical properties of biocomposites. At the fibre scale, XG and CNC increase the surface roughness of flax fibres, as well as their adhesion to epoxy resin with IFSS improved by 60 %, up to 22.3 MPa. At the composite scale, the treatments have a major influence on the cohesion of flax cell walls and microstructure of the biocomposites. Transverse tensile tests reveal both cohesive and adhesive interfacial failure.

Effect of Macro Fibers on the Permeability and Crack Surface Topography of Layered Fiber Reinforced Concrete.

This paper describes the effects of macro fibers on permeability and crack surface topography of layered fiber-reinforced concrete (FRC) specimens with different layering ratios under uniaxial tensile load. The crack permeability of layered FRC specimens is investigated by a self-designed permeability setup. The topographical analysis of crack surfaces is investigated by a custom-designed laser scanning setup. The results show that when the fiber volume content and layering ratio of the FRC layer are constant, the tensile toughness of layered FRC specimens depends on the proportion of steel fiber in macro fibers, and with an increase in the proportion of steel fiber, the tensile toughness of layered FRC specimens increases. For the layered FRC specimens, the crack permeability is much lower than that of the normal concrete (NC) specimen. A significant positive synergistic effect on crack impermeability can be achieved by the combination of steel fiber and polypropylene fiber in the SF80PP2.3 specimen. The crack surface roughness parameter (Rn) values of the NC layer in layered FRC specimens are all higher than those of the NC specimen, and the crack surface Rn of the FRC layer in layered FRC specimens is higher than that of the unlayered FRC specimens. This can effectively increase the head loss of cracks and reduce the crack permeability of layered FRC specimens.

Topographical characterization and permeability correlation of steel fiber reinforced concrete surface under freeze-thaw cycles and NaCl solution immersion

This study investigates the relationship between the surface topography of steel fiber reinforced concrete (SFRC) and both the freeze-thaw damage and permeability of the concrete matrix subjected to freeze-thaw cycles and immersion in a sodium chloride solution. Rapid freeze-thaw tests were conducted on concrete immersed in NaCl solution to introduce freeze-thaw damage. A custom-developed 3D laser-scanning device was employed to capture the surface topography information of concrete subjected to freeze-thaw cycles. Multivariate analysis was utilized to determine the suitable parameter for evaluating the roughness of the concrete surface. A correlation analysis was carried out between the surface topography of concrete and the freeze-thaw damage parameters, including mass loss (ΔWn), relative dynamic modulus of elasticity (RDME), and ultrasonic pulse velocity (Uv). A custom-designed vacuum permeability device was used to measure the permeability of concrete matrix. The relationship between the surface topography and permeability of concrete subjected to freeze-thaw damage is studied. The results show that the steel fibers significantly reduce the freeze-thaw damage and surface roughness of concrete subjected to freeze-thaw damage in the sodium chloride solution. Roughness number (RN) is the most representative parameter for evaluating the topographical characterization of concrete surface and can be used to quantify the surface topography of concrete exposed to freeze-thaw cycles. The absolute values of correlation coefficient between RN and its ΔWn, RDME, and Uv reach up to 0.89, which suggests that RN can indirectly evaluate the freeze-thaw damage of concrete. Furthermore, there exists a logarithmic relationship between RN and the permeability of the concrete matrix, with the correlation coefficient R2 exceeding 0.86. This relationship can be utilized to quickly estimate its permeability based on the surface roughness of SFRC exposed in cold coastal regions.

Cell Adhesion Behaviors on Spider Silk Fibers, Films, and Nanofibers

Silk-based materials have garnered attention for use as medical supplies due to their mechanical toughness and low cytotoxicity. Silkworm silk has been applied as surgical sutures for decades. In contrast, the utilization of spider silk is limited mainly because of its scarcity. Although the biomimicry of spider silk has been developed using recombinant protein expression systems with the use of genetic engineering, the product often results in lower molecular weight and a lack of the N- or C-terminal regions. The incomplete sequence of the spider silk-like protein prevents the objective evaluation of the native spider silk as a medical application and retards the development of spider silk-inspired materials. Here, we reeled the native spider silk directly from live spiders and investigated the cell adhesion behavior based on three kinds of surface topography of spider silk-based substrates, namely, fibers, films, and non-woven fabrics. The cell adhesion behavior was largely influenced by the surface micro/nanostructure rather than the wettability of the surface. This study will contribute to promote the utilization of spider silk in the medical field as a candidate for promising bio-based fibers in the context of sustainable development goals.

Simulation of surface asperities on a carbon fiber using molecular dynamics and fourier series decomposition to predict interfacial shear strength in polymer matrix composites

ABSTRACT The objective of this paper is to predict the fiber/matrix interfacial debond strength in composites. Atomic force microscopy (AFM) images of the surface topography of a de-sized carbon fiber reveal that there are surface asperities present at various length scales ranging from a nanometer to several microns. These asperities are likely caused by shrinkage of the polyacrylonitrile (PAN) precursor during the graphitization process. In order to bridge the length scales, a Fourier series-decomposition covering a range of asperity wavelengths and amplitudes is necessary to effectively capture the roughness of the fiber surface at different length scales. Further, once a surface asperity profile has been resolved into individual subcomponents using Fourier-decomposition, MD simulations can then be employed to obtain the interfacial shear strength of the subcomponent asperity of a given amplitude and wavelength. Finally, by recombining the peak interfacial shear force obtained from each of these subcomponents into the overall shear force for the fiber surface profile, the length-scale-averaged shear strength can be obtained for any given asperity. The objective of this paper is to use this novel approach to determine the interfacial shear strength of de-sized carbon fiber embedded in an epoxy matrix and compare predicted results with experimental data.

Carbon Fiber Surface Functional Landscapes: Nanoscale Topography and Property Distribution.

The ultimate properties of carbon fibers and their composites are largely dictated by the surface topography of the fibers and the interface characteristics, which are primarily influenced by the surface distribution of chemical functionalities and their interactions with the matrix resin. Nevertheless, nanoscale insights on the carbon fiber surface in relationship with its chemical modification are still rarely addressed. Here, we demonstrate a critical insight on the nanoscale surface topography characterization of modified novel carbon fibers using high-resolution atomic force microscopy at multiple length scales. We compare the nanoscale surface characteristics relevant to their role in controlling interfacial interactions for carbon fibers manufactured at two different tensions and two distinct chemically functionalized coatings. We used surface dimple (also known as nanopores) profiling, microroughness analysis, power spectral density analysis, and adhesion and electrostatic potential mapping to reveal the fine details of surface characteristics at different length scales. This analysis demonstrates that the carbon fibers processed at lower tension possess a higher fractal dimension with a more corrugated surface and higher surface roughness, which leads to increased surface adhesion and energy dissipation across nano- and microscales. Furthermore, electrochemical surface modification with amine- and fluoro-functional groups significantly masks the microroughness inherent to these fibers. This results in increased fractal dimension and decreased energy dissipation and adhesion due to the high chemical reactivity in the areas of asperities and surface defects combined with a significant increase in the surface potential, as revealed by Kelvin probe mapping. These local surface properties of carbon fibers are crucial for designing next-generation fiber composites with predictable interfacial strength and the overall mechanical performance by considering the fiber surface topography for proper control of interphase formation.

How Fiber Surface Topography Affects Interactions between Cells and Electrospun Scaffolds: A Systematic Review.

Electrospun scaffolds have a 3D fibrous structure that attempts to imitate the extracellular matrix in order to be able to host cells. It has been reported in the literature that controlling fiber surface topography produces varying results regarding cell–scaffold interactions. This review analyzes the relevant literature concerning in vitro studies to provide a better understanding of the effect that controlling fiber surface topography has on cell–scaffold interactions. A systematic approach following PRISMA, GRADE, PICO, and other standard methodological frameworks for systematic reviews was used. Different topographic interventions and their effects on cell–scaffold interactions were analyzed. Results indicate that nanopores and roughness on fiber surfaces seem to improve proliferation and adhesion of cells. The quality of the evidence is different for each studied cell–scaffold interaction, and for each studied morphological attribute. The evidence points to improvements in cell–scaffold interactions on most morphologically complex fiber surfaces. The discussion includes an in-depth evaluation of the indirectness of the evidence, as well as the potentially involved publication bias. Insights and suggestions about dose-dependency relationship, as well as the effect on particular cell and polymer types, are presented. It is concluded that topographical alterations to the fiber surface should be further studied, since results so far are promising.

Protein-induced decoration of applying MXene directly to UHMWPE fibers and fabrics for improved adhesion properties and electronic textiles

MXene, as an attractive functional and structural material with high conductivity, wettability, surface activity and plenty of superior mechanical properties, is applied for the first time to directly decorate ultra-high molecular weight polyethylene fiber (UHMWPE) and fabrics with a unique bovine serum albumin (BSA)-induced technology. The adoption of BSA successfully turns UHMWPE fiber into an adhesive platform toward the efficient assembly and wrapping of MXene. The results showed that the functionalization of MXene changed the UHMWPE fiber surface topography and increased the wettability and surface activity, which can enhance the mechanical engagement and offer sufficient reactive sites with resin matrix, providing efficiently improved interfacial properties. The interfacial shear strength between the UHMWPE/BSA/MXene fiber and epoxy increased by 116% when compared with pristine UHMWPE fiber. Besides, the peeling strength of MXene decorated UHMWPE fabric/rubber laminate demonstrates more than two times higher than the untreated UHMWPE fabric reinforced rubber composite. Furthermore, with the excellent conductivity of MXene, the UHMWPE/BSA/MXene fiber exhibits an electrical conductivity of 106 S/m, which is able to work as a conductor for the application of electronic textiles.

Tensile Behavior of Geometrically Irregular Bagasse Fiber

In the present work, an investigation on the surface topography and geometry variation of bagasse fibers was correlated with their mechanical properties via image analysis. The fibers were tested under a universal tensile testing machine and the diameter of the fibers was calculated using images obtained in a digital microscope. Furthermore, surface characterization and quantification were also performed using images obtained via SEM. The results showed that the surface roughness of alkali-treated bagasse fiber increased compared to that of the untreated one. Moreover, it was observed that the diameter variation of bagasse fiber along its length and among different fibers is not only variable but also unpredictable. The tensile test results revealed that bagasse fibers showed lower stress at a rupture with considerable scatter. It can be inferred that the synergistic effect of thick bagasse fiber, bagasse fiber diameter variations along its length and among fibers, and the fiber fracture mechanism establishes a local condition for fracture and resulted in such variations in tensile properties. Finally, the results clearly showed that the two-parameter Weibull fit the experimental data fairly well (R2=0.97). The Weibull modulus (m) was found to be 1.7, indicating that the strength distribution is high.

A Study of Fabrication Technique, Structural and Morphological Behavior of Polypropylene Reinforced with Short Natural Fiber Banana

With regard to the environmental aspect it would be very interesting if natural fibers like banana, jute, and coir could be used instead of artificial fibers and synthetic products as reinforcement in some applications. Banana .Natural fibers have many advantages compared to other man made fibers. The natural fiber composites may be used in everyday applications such as lampshades, suitcases, paperweight, helmets, shower and bath units. Polypropylene composites were fabricated with untreated and alkali treated jute fiber with 10-25% loading of fiber by weight and were designated at Polypropylene Banana Composite (PPBC). The composites of biodegradable Polypropylene (PP) reinforced with short jute natural fiber was prepared by melt mixing followed by hot press molding. The micro structural analysis and morphologies of the composites were studied via infrared spectroscopy (IR) and Scanning electron microscopy (SEM) techniques respectively. The extensive application of infrared spectroscopy is mainly due to the concept of group vibration. Any structural change like substitution or addition of groups or atoms in a molecule affects the relative mode of vibration of the group. This causes change in IR spectral band position, change in relative intensities and appearance of new bands and disappearance of any band and splitting of a single band into two or more bands. Infrared spectroscopy can also be used to increase the utility of fiber. It deals with the interaction of infrared light with matter. The former can indicate the presence of functional groups qualitatively and the latter can provide a semi quantitative measure of their concentrations. Electron Microscopy is most widely used to obtain information regarding the morphology of fiber surfaces, especially SEM (Scanning Electron Microscopy). Using SEM, it is easy to determine the differences of fiber surface topography after and before treatment, and hence the formation of fiber polymer composites. Fiber deboning was also observed for untreated and treated fiber pp matrix composite. It reveals that bonding between the fiber and the matrix at the interface may be improved. These indicate that there are some kinds of interfacial contact between fiber and pp matrix due to fiber treatment. The SEM can have a magnification range from a few times to several hundred thousand times.

Effect of surface treatments on push-out bond strength of calcium silicate-based cements to fiber posts

BackgroundTo evaluate the effect of surface treatments on the push-out bond strength of Biodentine (BD) and white mineral trioxide aggregate (WMTA) to fiber posts.MethodsTwo brands of fiber posts were used: Reblida post; RP and RelyX post; RX. Each type of post (n = 80/group) was divided into four groups (n = 20/group) and exposed to surface treatment as follows: Control (no treatment), sandblasting (SB), hydrofluoric acid (HF), and TiF4 4 wt/v%. Each group was further subdivided into two subgroups (n = 10/subgroup) based on the type of CSCs used as follows: Subgroup A: BD and Subgroup B: WMTA. Push-out bond strength of BD and WMTA to glass fiber posts was assessed. Data were statistically analyzed using three-way ANOVA and Tukey’s test. A Weibull analysis was performed on the push-out bond strength data.ResultsBD showed higher bond strength than WMTA (P < 0.001). The push-out bond strength for posts treated with TiF4 4 wt/v% showed greater bond strength than the other surface treatments (P < 0.05). The BD/RP-TiF4 4 wt/v% showed the greater characteristic bond strength (σ0) (15.93) compared with the other groups. Surface treatments modified the surface topography of glass fiber posts.ConclusionsThe BD/RP-TiF4 4 wt/v% showed greater bond strength compared with the other groups. The TiF4 4 wt/v% surface treatment enhanced the bond strength of BD and WMTA to glass fiber posts than the other treatments. Surface treatment of fiber post with TiF4 4 wt/v% could be used to improve the bond strength with calcium silicate-based cements.

Carbon fiber coating with MWCNT in the presence of polyethyleneimine of different molecular weights and the effect on the interfacial shear strength of thermoplastic and thermosetting carbon fiber composites

The effect of multi-walled carbon nanotubes (MWCNT) coating in the presence of polyethyleneimine (PEI) of different molecular weights (MW) on the interfacial shear strength (IFSS) of carbon fiber/acrylonitrile–butadiene–styrene (ABS) and carbon fiber/epoxy composites was investigated. The IFSS between the carbon fiber and the polymer was evaluated by means of single fiber microbonding test. The results indicated that uses of the carbon fibers uncoated and coated with pristine, low MW PEI-treated, and high MW PEI-treated MWCNT significantly influenced the IFSS of both thermoplastic and thermosetting carbon fiber composites as well as the carbon fiber surface topography. The incorporation of low MW (about 1300) PEI into the carboxylated MWCNT was more effective not only to uniformly coat the carbon fiber with the MWCNT but also to improve the interfacial bonding strength between the carbon fiber and the polymer than that of high MW (about 25,000) PEI. In addition, carbon fiber/epoxy composite exhibited the IFSS much higher than carbon fiber/ABS composite due to the chemical interactions between the epoxy resin and amine groups existing in the PEI-treated MWCNT.

Hierarchical fibrous guiding cues at different scales influence linear neurite extension

Surface topographies at micro- and nanoscales can influence different cellular behavior, such as their growth rate and directionality. While different techniques have been established to fabricate 2-dimensional flat substrates with nano- and microscale topographies, most of them are prone to high costs and long preparation times. The 2.5-dimensional fiber platform presented here provides knowledge on the effect of the combination of fiber alignment, inter-fiber distance (IFD), and fiber surface topography on contact guidance to direct neurite behavior from dorsal root ganglia (DRGs) or dissociated primary neurons. For the first time, the interplay of the micro-/nanoscale topography and IFD is studied to induce linear nerve growth, while controlling branching. The results demonstrate that grooved fibers promote a higher percentage of aligned neurite extension, compensating the adverse effect of increased IFD. Accordingly, maximum neurite extension from primary neurons is achieved on grooved fibers separated by an IFD of 30 μm, with a higher percentage of aligned neurons on grooved fibers at a large IFD compared to porous fibers with the smallest IFD of 10 µm. We further demonstrate that the neurite “decision-making” behavior on whether to cross a fiber or grow along it is not only dependent on the IFD but also on the fiber surface topography. In addition, axons growing in between the fibers seem to have a memory after leaving grooved fibers, resulting in higher linear growth and higher IFDs lead to more branching. Such information is of great importance for new material development for several tissue engineering applications. Statement of SignificanceOne of the key aspects of tissue engineering is controlling cell behavior using hierarchical structures. Compared to 2D surfaces, fibers are an important class of materials, which can emulate the native ECM architecture of tissues. Despite the importance of both fiber surface topography and alignment to direct growing neurons, the current state of the art did not yet study the synergy between both scales of guidance. To achieve this, we established a solvent assisted spinning process to combine these two crucial features and control neuron growth, alignment, and branching. Rational design of new platforms for various tissue engineering and drug discovery applications can benefit from such information as it allows for fabrication of functional materials, which selectively influence neurite behavior.

Investigation on the Physicochemical and Mechanical Properties of Novel Alkali-treated Phaseolus vulgaris Fibers

ABSTRACT This investigation is aimed to analyze the effect of sodium hydroxide (NaOH) treatment on the physical, chemical, structural, thermal and surface topography of Phaseolus vulgaris fibers (PVFs). The surface of raw PVFs was modified by soaking with 5% NaOH solution for 15, 30, 45 and 60 min. The various functional groups of the alkali-treated PVFs (APVFs) were studied Fourier-transform infrared spectroscopy. The outcomes of thermogravimetric analysis evident that the optimum treatment time for 5% NaOH was 45 min. It was noticed that optimally treated PVFs have higher cellulose (69.48 wt.%), crystallinity index (52.27%) and lower hemicellulose (4.30 wt.%), lignin (7.02 wt.%) contents. The thermogravimetric analysis (TGA) of PVFs also revealing moderate thermal stability was observed; atomic force microscopy (AFM) investigation inveterates that the surface of the fiber is rough and it will be a potential reinforcement for polymer composites.

Thermogravimetry and Interfacial Characterization of Alkaline Treated Cantala fiber/Microcrystalline Cellulose-Composite

The effects of alkali treatment on morphology, thermal stability, and interfacial shear strength of cantala fiber (CF) were investigated. CF untreated and treated with 6% sodium hydroxide (NaOH) for soaking times 3 h, 6 h, 9 h, 12 h, and 15 h. The results of untreated and treated fibers were observed by the Scanning Electron Microscope (SEM). The results of scanning electron microscopy on the CF surface showed cleaner fibers and increased surface roughness by alkali treatment. Alkali treatment has changed the characteristics of the fiber surface topography as seen in the SEM results. CF with soaking over 6 h occurs of damage to the fibrils and fiber structure. Prolonged treatment results in poor fiber quality. Thermogravimetric analysis (TGA) is used to measure the amount and rate of change in CF weight that is not treated and treated. The results of the study show that alkaline treatment improves most of the fiber’s properties. The thermal stability of treated CF is higher than that of untreated. Interface shear strength tests show that fiber with 6% treatment, and 6 h soaking, gives the most upper strength of 3.67 MPa, an increase of 47.39% if compared before treatment. Flexural strength and modulus of elasticity were increased with alkali treatment and the addition of microcrystalline cellulose.

Directed self-assembly of silica nanoparticles in ionic liquid-spun cellulose fibers

The application range of man-made cellulosic fibers is limited by the absence of cost- and manufacturing-efficient strategies for anisotropic hierarchical functionalization. Overcoming these bottlenecks is therefore pivotal in the pursuit of a future bio-based economy. Here, we demonstrate that colloidal silica nanoparticles (NPs), which are cheap, biocompatible and easy to chemically modify, enable the control of the cross-sectional morphology and surface topography of ionic liquid-spun cellulose fibers. These properties are tailored by the silica NPs’ surface chemistry and their entry point during the wet-spinning process (dope solution DSiO2 or coagulation bath CSiO2). For CSiO2-modified fibers, the coagulation mitigator dimethylsulphoxide allows for controlling the surface topography and the amalgamation of the silica NPs into the fiber matrix. For dope-modified fibers, we hypothesize that cellulose chains act as seeds for directed silica NP self-assembly. This results for DSiO2 in discrete micron-sized rods, homogeneously distributed throughout the fiber and for glycidoxy-surface modified DSiO2@GLYEO in nano-sized surface aggregates and a cross-sectional core-shell fiber morphology. Furthermore, the dope-modified fibers display outstanding strength and toughness, which are both characteristic features of biological biocomposites.

Evaluation of composite interfacial properties based on carbon fiber surface chemistry and topography: Nanometer-scale wetting analysis using molecular dynamics simulation

According to surface chemistry and topography of different high-modulus carbon fiber (HMCF), interfacial properties of various HMCF composite were evaluated, and nanoscale wetting analysis of HMCF were studied using experimental methods and molecular dynamics simulation. Hierarchical amount of active functional groups and nanoscale grooves were detected on the surface of pristine HMCF (p-HMCF), anodic oxidized HMCF (a-HMCF) and sized HMCF (s-HMCF). Remarkable enhancements in interfacial properties of a-HMCF and s-HMCF composites were obtained, which was ascribed to free-void interface from improved surface energy and wettability. Poor interfacial bonding of p-HMCF composites was due to generation of many nanobubbles with pinned contact lines during the wetting of the surface microgrooves with high aspect ratio and chemical inertness. Schematic of interfacial compatibility mechanisms was proposed to illustrate the correlation between surface features of carbon surface and interfacial properties of their composites.

Capillary rise of polydimethylsiloxane around a poly(ethylene terephthalate) fiber versus viscosity: Existence of a sharp transition in the dynamic wetting behavior

HypothesisSince the emergence of the molecular-kinetic theory and the hydrodynamic approach, it is generally accepted that the displacement of the contact line is controlled by the viscous or frictional channel of energy dissipation for respectively high-viscosity and low-viscosity liquids. However, how the dissipation switches from one channel to another is still unknown. We therefore hypothesized that, by progressively changing the viscosity of a liquid, a better understanding of the underlying mechanism driving this wetting dynamic transition would be obtained. ExperimentsPerforming capillary rise experiments of polydimethylsiloxane on a poly(ethylene terephthalate) fiber at different temperatures, i.e. at different liquid viscosities, we characterized the transition between the viscous and frictional regimes. The fiber surface topography was also characterized and its effect on the wetting dynamics was quantified. FindingsThe wetting dynamics switched from one regime to the other in a very short viscosity interval. Besides, the wetting behavior in the transition region is sensitive to the fiber surface topography. The presence or the absence of a liquid rim ahead of the contact line actually determines the dominant channel of dissipation.

Adhesion of carbon fibers to amine hardened epoxy resin: Influence of ammonia plasma functionalization of carbon fibers

The modification of carbon fiber surface properties represents a powerful tool to improve the adhesion between fibers and polymeric matrix in carbon fiber reinforced polymers. In the presented work the surface of untreated carbon fibers, taken from the production process directly after carbonization, is functionalized by a low pressure ammonia plasma treatment. Compared to the untreated fibers an enhanced concentration of surface nitrogen functionalities and an increased surface energy are observed. This leads to an improved wetting behavior, similar to that of carbon fibers activated by anodic oxidation. No changes of the fiber surface topography on micro- and on nanoscale are induced by the plasma treatment. Compared to the untreated fiber no increase of interfacial fracture toughness between the plasma treated fibers and an amine hardened epoxy resin is detected by single fiber push-out tests. Anodically oxidized fibers, in contrast, show a significant increase of interfacial fracture toughness. The results suggest, that adhesion of carbon fibers to an amine hardened epoxy resin is dominantly enhanced by interactions between surface oxygen functionalities and the components of the resin. In contrast, nitrogen surface functionalities appear to be of minor importance for fiber matrix adhesion in carbon fiber reinforced amine hardened epoxy resin.