scholarly journals Hot Embossing of Micro-Pyramids into Thermoset Thiol-Ene Film

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2291
Author(s):  
Dalius Jucius ◽  
Algirdas Lazauskas ◽  
Viktoras Grigaliūnas ◽  
Asta Guobienė ◽  
Linas Puodžiukynas
Keyword(s):  
Surface Roughness ◽  
Shape Memory ◽  
Shape Memory Polymer ◽  
Hot Embossing ◽  
High Fidelity ◽  
Roughness Parameters ◽  
Force Microscopy ◽  
Rubbery State ◽  
Atomic Force ◽  
Shape Memory Films

This paper presents the first attempt to texturize a fully crosslinked thermoset shape memory polymer using a hot embossing technique. UV-cured thiol-ene films were successfully embossed with anisotropically-etched Si (100) stamps at a temperature of 100 °C, which is about 50 °C above the glass transition temperature of the polymer. The low storage modulus of the polymer in a rubbery state allowed us to permanently emboss random micro-pyramidal patterns onto the surface of the film with high fidelity by applying 30 MPa pressure for 1 h. Atomic force microscopy (AFM) investigation showed perfect replication of the stamp micropattern with typical height of the largest inverted pyramids close to 0.7 µm and lateral dimensions in the range of 1–2 µm. Changes in surface roughness parameters of the embossed thiol-ene films after annealing them at 100 °C for 1 h or storing for 2 months in air at standard room conditions were negligible. The achieved results open new perspectives for the simple and inexpensive hot embossing technique to be applied for the micropatterning of prepolymerized thermoset shape memory films as an alternative to micropatterning using UV casting.

scholarly journals Assessing the Functional Properties of TiZr Nanotubular Structures for Biomedical Applications, through Nano-Scratch Tests and Adhesion Force Maps

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 900
Author(s):  
Maria Vardaki ◽  
Aida Pantazi ◽  
Ioana Demetrescu ◽  
Marius Enachescu
Keyword(s):  
Surface Roughness ◽  
Functional Properties ◽  
Bacterial Adhesion ◽  
Biomedical Applications ◽  
Adhesion Force ◽  
Roughness Parameters ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Mean ◽  
Scratch Tests

In this work we present the results of a functional properties assessment via Atomic Force Microscopy (AFM)-based surface morphology, surface roughness, nano-scratch tests and adhesion force maps of TiZr-based nanotubular structures. The nanostructures have been electrochemically prepared in a glycerin + 15 vol.% H2O + 0.2 M NH4F electrolyte. The AFM topography images confirmed the successful preparation of the nanotubular coatings. The Root Mean Square (RMS) and average (Ra) roughness parameters increased after anodizing, while the mean adhesion force value decreased. The prepared nanocoatings exhibited a smaller mean scratch hardness value compared to the un-coated TiZr. However, the mean hardness (H) values of the coatings highlight their potential in having reliable mechanical resistances, which along with the significant increase of the surface roughness parameters, which could help in improving the osseointegration, and also with the important decrease of the mean adhesion force, which could lead to a reduction in bacterial adhesion, are providing the nanostructures with a great potential to be used as a better alternative for Ti implants in dentistry.

scholarly journals Surface of Alumina Films after Prolonged Breakdowns in Galvanostatic Anodization

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Christian Girginov ◽  
Stephan Kozhukharov
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Electrode Surface ◽  
Roughness Parameters ◽  
Anodic Films ◽  
Force Microscopy ◽  
Alumina Films ◽  
Anodization Time ◽  
Atomic Force ◽  
Current Densities

Breakdown phenomena are investigated at continuous isothermal (20∘C) and galvanostatic (0.2–5 mA cm−2) anodizing of aluminum in ammonium salicylate in dimethylformamide (1 M AS/DMF) electrolyte. From the kinetic -curves, the breakdown voltage () values are estimated, as well as the frequency and amplitude of oscillations of formation voltage () at different current densities. The surface of the aluminum specimens was studied using atomic force microscopy (AFM). Data on topography and surface roughness parameters of the electrode after electric breakdowns are obtained as a function of anodization time. The electrode surface of anodic films, formed with different current densities until the same charge density has passed (2.5 C cm−2), was assessed. Results are discussed on the basis of perceptions of avalanche mechanism of the breakdown phenomena, due to the injection of electrons and their multiplication in the volume of the film.

Surface Roughness

2019 ◽  
pp. 28-53
Author(s):  
C. Mathew Mate ◽  
Robert W. Carpick
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Contact Friction ◽  
Radius Of Curvature ◽  
Roughness Parameters ◽  
Force Microscopy ◽  
Fractal Surfaces ◽  
Atomic Force ◽  
The Mean ◽  
Physical Phenomena

When two surfaces are brought into contact, they first touch where the summits of the surface asperities make contact. Consequently, surface roughness or topography strongly influences those physical phenomena associated with contact: friction, adhesion, and wear. This chapter discusses techniques for measuring the roughness of surfaces and the parameters frequently used to characterize this roughness. As atomic force microscopy (AFM) and optical interferometry are currently the predominant tools for characterizing roughness, these techniques are discussed at some length. Examples are given for determining not only the standard roughness parameters (the standard deviation of surface heights, the mean radius of curvature of asperity summits, waviness, and the average and rms of surface heights), but also for determining the surface roughness power spectrum, which has gained importance in recent tribology theories. The topography of self-affine fractal surfaces is also discussed along with the tribological importance of these surfaces.

scholarly journals Bionic effects of nano hydroxyapatite dentifrice on demineralised surface of enamel post orthodontic debonding: in-vivo split mouth study

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Purva Verma ◽  
Srirengalakshmi Muthuswamy Pandian
Keyword(s):  
Surface Roughness ◽  
Enamel Surface ◽  
Roughness Parameters ◽  
Force Microscopy ◽  
Atomic Force ◽  
Group I ◽  
Significant Difference ◽  
Envelope Method ◽  
Group Ii

Abstract Background Orthodontic debonding procedure produces inevitable enamel surface alterations, sequelae to which are enamel demineralization, sensitivity and retention of pigments. Several agents have been employed to counterbalance the same. The purpose of this study was (1) To evaluate the hypothesis that no significant difference exists in the remineralising potential of nano hydroxyapatite (NanoHAP) dentifrice and fluoridated dentifrice after orthodontic debonding, (2) To estimate the enamel topographic parameters following use of nano HAP dentifrice, post orthodontic debonding. Methods Sixty upper first bi-cuspids (30 subjects) planned for therapeutic extraction for the orthodontic treatment were bonded with a light cured adhesive. Envelope method of randomisation was followed in this prospective in-vivo study. In each subject, one of the first premolar brackets was debonded using a debonding plier and polished following standard protocols. Envelope method of randomisation was used to determine the side of the premolar to be debonded first. Patient was advised to use fluoridated (Group I) dentifrice for the first 15 days, then the first premolar was covered with a heavy-bodied putty cap, extracted and subjected to atomic force microscopy (AFM). Contralateral first premolar was then debonded and polished using similar protocol, and patient was advised to use nano hydroxyapatite dentifrice (Group II) for next 15 days. The premolar was then extracted and analyzed for surface roughness using AFM. The remineralizing potential of dentifrices was assessed by evaluating surface roughness parameters of the two groups and were compared using a two-sample t test. Results A significant difference was found amongst Group I (Fluoridated dentifrice) and Group II (NanoHAP dentifrice) (p > 0.001***) for enamel surface roughness variables which reflect remineralising potential of dentifrices. Group II showed significantly lesser value of surface roughness characteristics. Conclusions NanoHAP dentifrice was shown, after 15 days, to be superior to fluoridated dentifrice in remineralising enamel post orthodontic debonding.

Application of focused ion-beam sampling for sidewall-roughness measurement of free-standing sub-μm objects by atomic force microscopy

Microscopy ◽  
2020 ◽  
Vol 69 (1) ◽  
pp. 11-16
Author(s):  
Takaharu Nagatomi ◽  
Tatsuya Nakao ◽  
Yoko Fujimoto
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Focused Ion Beam ◽  
Microelectromechanical Systems ◽  
Ion Beam ◽  
Sampling Technique ◽  
Roughness Parameters ◽  
Free Standing ◽  
Force Microscopy ◽  
Atomic Force

Abstract In the present study, a free-standing object-sampling technique for microelectromechanical systems (MEMS) is developed to measure their sidewall surface roughnesses by atomic force microscopy (AFM). For this purpose, a conventional focused ion beam (FIB) sampling technique widely used for cross-sectional transmission electron microscope specimen preparation was applied. The sub-nm-order roughness parameters were quantitatively measured for sidewalls of Si-bridge test samples. The roughness parameters were compared before and after H2 annealing treatment, which induced smoothing of the surface by migration of the Si atoms. The reduction in the surface roughness by a factor of approximately one-third with 60-s H2 annealing was quantitatively evaluated by AFM. The present study confirms that the developed FIB–AFM technique is one potential approach for quantitatively evaluating the surface-roughness parameters on the oblique faces of free-standing objects in MEMS devices.

Etching Performance Improvement On Semiconductor Silicon Wafers With Redesigned Etching Drum

2011 ◽  
Author(s):  
Rozzeta Dolah ◽  
Hamidon Musa ◽  
Astuty Amrin
Keyword(s):  
Surface Roughness ◽  
Performance Improvement ◽  
Silicon Wafer ◽  
Etching Process ◽  
Wafer Surface ◽  
Roughness Parameters ◽  
Force Microscopy ◽  
Atomic Force ◽  
Empty Slot ◽  
Empty Area

Proses etching atau punaran melibatkan pelbagai tindak balas kimia dan sangat penting dalam menentukan kualiti wafer silikon. Projek ini menyelesaikan masalah utama wafer ketika proses punaran, iaitu keserakan data pembuangan sisa wafer di sepanjang dram punaran. Cecair punaran yang digunakan dalam projek ini terdiri daripada komposisi asid HNO3, HF, and CH3COOH. Dram punaran telah diubahsuai untuk menyelesaikan masalah pembuangan sisa wafer yang rendah di setiap wafer pertama dan terakhir dalam sesuatu kompatmen dram. Tujuan utamanya adalah untuk mengurangkan jurang perbezaan variasi dalam pembuangan sisa wafer, di mana nilai pembuangan silicon adalah rendah berbanding pembuangan silicon wafer di tengah kompatmen. Antara cadangan tersebut adalah menambahkan "kepingan wafer PVC tahan asid" di sebelah wafer pertama dan terakhir dalam setiap kompatmen. Selepas memperoleh keputusan yang memberangsangkan, kepingan PVC tersebut dikekalkan dalam rekabentuk dram yang baru. Sifat wafer pertama dan terakhir dinilaikan untuk memastikan tiada kualiti yang terjejas berbanding wafer-wafer di tengah kompatmen. Morfologi permukaan dan kekasaran wafer (purata kekasaran;Ra dan kekasaran "skewness";Rms) menggunakan mikroskop tujahan atom (AFM) dianalisis untuk dibandingkan dengan dram lama. Keseragaman pembuangan wafer tanpa masalah pembuangan rendah di hujung kompatmen telah diperhatikan. Kata kunci: Proses punaran, permukaan "Micromachining", wafer silicon, pembuangan silicon wafer, kekasaran permukaan wafer silikon Etching process involves various chemical reactions and reflects significantly on the silicon wafer quality. The paper addresses the major problem on wafers during etching that is wafer removal distribution throughout etching drum compartment. The etchant used in this study were the composition of HNO3, HF, and CH3COOH. The etching drum has been redesigned to overcome the lower removal problem at the end of each compartment and to reduce the big disparity in wafer removal distribution. The proposed idea is to install a piece of "circumferential acid resistant PVC wafer" for the remaining empty slot (empty area without wafers) at each end of a compartment. The permanent PVC piece with certain gap at each end is then fabricated for the new drum design. The characteristics of the end wafers are compared with other wafers in the compartment to study the etching difference that leads to this problem. Surface morphology and surface roughness parameters (arithmetic roughness mean; Ra and surface skewness [roughness root mean square]; Rms) using atomic force microscopy (AFM) comparison between old drum design (big wafer gap) and new drum design (smaller gap with additional PVC chip) had been analyzed. The uniformity without lower removal problem at the end compartment is observed in removal distribution graph. Key words: Etching process; surface micromachining; silicon wafer; etching removal; silicon wafer surface roughness

Surface roughness measurements of vanadium-contaminated fluidized cracking catalysts by atomic force microscopy

1996 ◽  
Vol 54 ◽  
pp. 866-867
Author(s):  
H. Kinney ◽  
M.L. Occelli ◽  
S.A.C. Gould
Keyword(s):  
Surface Roughness ◽  
Zeolite Y ◽  
Atomic Level ◽  
Microporous Structure ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After ◽  
Roughness Measurements ◽  
Cracking Catalysts

For this study we have used a contact mode atomic force microscope (AFM) to study to topography of fluidized cracking catalysts (FCC), before and after contamination with 5% vanadium. We selected the AFM because of its ability to well characterize the surface roughness of materials down to the atomic level. It is believed that the cracking in the FCCs occurs mainly on the catalysts top 10-15 μm suggesting that the surface corrugation could play a key role in the FCCs microactivity properties. To test this hypothesis, we chose vanadium as a contaminate because this metal is capable of irreversibly destroying the FCC crystallinity as well as it microporous structure. In addition, we wanted to examine the extent to which steaming affects the vanadium contaminated FCC. Using the AFM, we measured the surface roughness of FCCs, before and after contamination and after steaming.We obtained our FCC (GRZ-1) from Davison. The FCC is generated so that it contains and estimated 35% rare earth exchaged zeolite Y, 50% kaolin and 15% binder.

Brittle Behaviour in Aspirin Crystals: Evidence of Spalling Fracture

2020 ◽  
Author(s):  
Benjamin P. A. Gabriele ◽  
Craig J. Williams ◽  
Douglas Stauffer ◽  
Brian Derby ◽  
Aurora J. Cruz-Cabeza
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Single Crystals ◽  
Spalling Fracture ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging

<div> <div> <div> <p>Single crystals of aspirin form I were cleaved and indented on their dominant face. Upon inspection, it was possible to observe strongly anisotropic shallow lateral cracks due to the extreme low surface roughness after cleavage. Atomic Force Microscopy (AFM) imaging showed spalling fractures nucleating from the indent corners, forming terraces with a height of one or two interplanar spacings d100. The formation of such spalling fractures in aspirin was rationalised using basic calculations of attachment energies, showing how (100) layers are poorly bonded when compared to their relatively higher intralayer bonding. An attempt at explaining the preferential propagation of these fractures along the [010] direction is discussed. </p> </div> </div> </div>

Brittle Behaviour in Aspirin Crystals: Evidence of Spalling Fracture

2020 ◽  
Author(s):  
Benjamin P. A. Gabriele ◽  
Craig J. Williams ◽  
Douglas Stauffer ◽  
Brian Derby ◽  
Aurora J. Cruz-Cabeza
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Single Crystals ◽  
Spalling Fracture ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging

<div> <div> <div> <p>Single crystals of aspirin form I were cleaved and indented on their dominant face. Upon inspection, it was possible to observe strongly anisotropic shallow lateral cracks due to the extreme low surface roughness after cleavage. Atomic Force Microscopy (AFM) imaging showed spalling fractures nucleating from the indent corners, forming terraces with a height of one or two interplanar spacings d100. The formation of such spalling fractures in aspirin was rationalised using basic calculations of attachment energies, showing how (100) layers are poorly bonded when compared to their relatively higher intralayer bonding. An attempt at explaining the preferential propagation of these fractures along the [010] direction is discussed. </p> </div> </div> </div>

scholarly journals Atomic force microscopy comparative analysis of the surface roughness of two posterior chamber phakic intraocular lens models: ICL versus IPCL

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Juan Gros-Otero ◽  
Samira Ketabi ◽  
Rafael Cañones-Zafra ◽  
Montserrat Garcia-Gonzalez ◽  
Cesar Villa-Collar ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Intraocular Lenses ◽  
Posterior Chamber ◽  
Anterior Surface ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Phakic Intraocular Lenses ◽  
Roughness Measurements

Abstract Background To compare the anterior surface roughness of two commercially available posterior chamber phakic intraocular lenses (IOLs) using atomic force microscopy (AFM). Methods Four phakic IOLs were used for this prospective, experimental study: two Visian ICL EVO+ V5 lenses and two iPCL 2.0 lenses. All of them were brand new, were not previously implanted in humans, were monofocal and had a dioptric power of − 12 diopters (D). The anterior surface roughness was assessed using a JPK NanoWizard II® atomic force microscope in contact mode immersed in liquid. Olympus OMCL-RC800PSA commercial silicon nitride cantilever tips were used. Anterior surface roughness measurements were made in 7 areas of 10 × 10 μm at 512 × 512 point resolution. The roughness was measured using the root-mean-square (RMS) value within the given regions. Results The mean of all anterior surface roughness measurements was 6.09 ± 1.33 nm (nm) in the Visian ICL EVO+ V5 and 3.49 ± 0.41 nm in the iPCL 2.0 (p = 0.001). Conclusion In the current study, we found a statistically significant smoother anterior surface in the iPCL 2.0 phakic intraocular lenses compared with the VISIAN ICL EVO+ V5 lenses when studied with atomic force microscopy.

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