Academic literature on the topic 'Silica nanochannel'
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Journal articles on the topic "Silica nanochannel":
1
Zucchetto, Nicola, and Dominik Brühwiler. "Tuning the aspect ratio of arrays of silica nanochannels." RSC Advances 5, no. 91 (2015): 74638–44. http://dx.doi.org/10.1039/c5ra16913e.
2
Morikawa, Kyojiro, Yutaka Kazoe, Yuto Takagi, Yoshiyuki Tsuyama, Yuriy Pihosh, Takehiko Tsukahara, and Takehiko Kitamori. "Advanced Top-Down Fabrication for a Fused Silica Nanofluidic Device." Micromachines 11, no. 11 (November 9, 2020): 995. http://dx.doi.org/10.3390/mi11110995.
Abstract:
Nanofluidics have recently attracted significant attention with regard to the development of new functionalities and applications, and producing new functional devices utilizing nanofluidics will require the fabrication of nanochannels. Fused silica nanofluidic devices fabricated by top-down methods are a promising approach to realizing this goal. Our group previously demonstrated the analysis of a living single cell using such a device, incorporating nanochannels having different sizes (102–103 nm) and with branched and confluent structures and surface patterning. However, fabrication of geometrically-controlled nanochannels on the 101 nm size scale by top-down methods on a fused silica substrate, and the fabrication of micro-nano interfaces on a single substrate, remain challenging. In the present study, the smallest-ever square nanochannels (with a size of 50 nm) were fabricated on fused silica substrates by optimizing the electron beam exposure time, and the absence of channel breaks was confirmed by streaming current measurements. In addition, micro-nano interfaces between 103 nm nanochannels and 101 μm microchannels were fabricated on a single substrate by controlling the hydrophobicity of the nanochannel surfaces. A micro-nano interface for a single cell analysis device, in which a nanochannel was connected to a 101 μm single cell chamber, was also fabricated. These new fabrication procedures are expected to advance the basic technologies employed in the field of nanofluidics.
3
Chen, Gengbiao, and Zhiwen Liu. "Effect of Hydrophobic Silica Nanochannel Structure on the Running Speed of a Colloidal Damper." Applied Sciences 11, no. 15 (July 24, 2021): 6808. http://dx.doi.org/10.3390/app11156808.
Abstract:
A colloidal damper (CD) can dissipate a significant amount of vibrations and impact energy owing to the interface power that is generated when it is used. It is of great practical significance to study the influence of the nanochannel structure of hydrophobic silica gel in the CD damping medium on the running speed of the CD. The fractal theory was applied to observe the characteristics of the micropore structure of the hydrophobic silica gel by scanning electron microscopy (SEM), the primary particles were selected to carry out fractal analysis, and the two-dimensional fractal dimension of the pore area and the tortuous fractal dimension of the hydrophobic silica gel pore structure were calculated. The fractal percolation model of water in hydrophobic silica nanochannels based on the slip theory could thus be obtained. This model revealed the relationship between the micropore structure parameters of the silica gel and the running speed of the CD. The CD running speed increases with the addition of grafted molecules and the reduction in pore size of the silica gel particles. Continuous loading velocity testing of the CD loaded with hydrophobic silica gels with different pore structures was conducted. By comparing the experimental results with the calculation results of the fractal percolation model, it was determined that the fractal percolation model can better characterize the change trend of the CD running velocity for the first loading, but the fractal dimension was changed from the second loading, caused by the small amount of water retained in the nanochannel, leading to the failure of fractal characterization.
4
Sokolov, I., V. Kalaparthi, D. O. Volkov, S. Palantavida, N. E. Mordvinova, O. I. Lebedev, and J. Owens. "Control and formation mechanism of extended nanochannel geometry in colloidal mesoporous silica particles." Physical Chemistry Chemical Physics 19, no. 2 (2017): 1115–21. http://dx.doi.org/10.1039/c6cp07057d.
5
Fernández, Iñigo, Alfredo Sánchez, Paula Díez, Paloma Martínez-Ruiz, Prospero Di Pierro, Raffaele Porta, Reynaldo Villalonga, and José M. Pingarrón. "Nanochannel-based electrochemical assay for transglutaminase activity." Chem. Commun. 50, no. 87 (2014): 13356–58. http://dx.doi.org/10.1039/c4cc05083e.
6
Yang, Qian, Xingyu Lin, Yafeng Wang, and Bin Su. "Nanochannels as molecular check valves." Nanoscale 9, no. 46 (2017): 18523–28. http://dx.doi.org/10.1039/c7nr05924h.
7
Yan, Fei, Jie Chen, Qifan Jin, Huaxu Zhou, Ajabkhan Sailjoi, Jiyang Liu, and Weizhong Tang. "Fast one-step fabrication of a vertically-ordered mesoporous silica-nanochannel film on graphene for direct and sensitive detection of doxorubicin in human whole blood." Journal of Materials Chemistry C 8, no. 21 (2020): 7113–19. http://dx.doi.org/10.1039/d0tc00744g.
8
Zhang, Wenfei, and Dongqing Li. "Low speed water flow in silica nanochannel." Chemical Physics Letters 450, no. 4-6 (January 2008): 422–25. http://dx.doi.org/10.1016/j.cplett.2007.11.043.
9
Ding, Jialian, Xinru Li, Lin Zhou, Rongjie Yang, Fei Yan, and Bin Su. "Electrodeposition of nickel nanostructures using silica nanochannels as confinement for low-fouling enzyme-free glucose detection." Journal of Materials Chemistry B 8, no. 16 (2020): 3616–22. http://dx.doi.org/10.1039/c9tb02472g.
10
Morikawa, Kyojiro, Ryoichi Ohta, Kazuma Mawatari, and Takehiko Kitamori. "Metal-Free Fabrication of Fused Silica Extended Nanofluidic Channel to Remove Artifacts in Chemical Analysis." Micromachines 12, no. 8 (July 31, 2021): 917. http://dx.doi.org/10.3390/mi12080917.
Abstract:
In microfluidics, especially in nanofluidics, nanochannels with functionalized surfaces have recently attracted attention for use as a new tool for the investigation of chemical reaction fields. Molecules handled in the reaction field can reach the single–molecule level due to the small size of the nanochannel. In such surroundings, contamination of the channel surface should be removed at the single–molecule level. In this study, it was assumed that metal materials could contaminate the nanochannels during the fabrication processes; therefore, we aimed to develop metal-free fabrication processes. Fused silica channels 1000 nm-deep were conventionally fabricated using a chromium mask. Instead of chromium, electron beam resists more than 1000 nm thick were used and the lithography conditions were optimized. From the results of optimization, channels with 1000 nm scale width and depth were fabricated on fused silica substrates without the use of a chromium mask. In nanofluidic experiments, an oxidation reaction was observed in a device fabricated by conventional fabrication processes using a chromium mask. It was found that Cr6+ remained on the channel surfaces and reacted with chemicals in the liquid phase in the extended nanochannels; this effect occurred at least to the micromolar level. In contrast, the device fabricated with metal-free processes was free of artifacts induced by the presence of chromium. The developed fabrication processes and results of this study will be a significant contribution to the fundamental technologies employed in the fields of microfluidics and nanofluidics.
Dissertations / Theses on the topic "Silica nanochannel":
1
Basnig, Deomila. "Élaboration de films minces de silice pour des applications en chimie analytique." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0102.
Abstract:
Un film orienté à base de silice mésoporeuse sur une électrode FTO a été préparé par une approche d'auto-assemblage assistée par électrochimie (EASA). Un potentiel de -1,5 V a été appliqué à l'électrode FTO contenant un précurseur de silice préhydrolysée (par exemple, l'orthosilicate de tétraéthyle), en présence d'un modèle (par exemple, le bromure de cétrimonium) et d'un électrolyte. Cette approche permet de générer des nanocanaux de silice alignés verticalement avec des tailles de pores ajustables entre 2 et 3 nm, selon le modèle. Ce travail a montré le comportement voltammétrique et la sélectivité du film de silice mésoporeuse vis-à-vis de divers cations chargés positivement de nature, de taille et de charge différentes. Les résultats ont montré une accumulation et une sélectivité favorisant l'ion le moins chargé positivement : MB⁺ > PQ²⁺ > DQ²⁺ > Ru(bpy)₃²⁺ > Ru(NH₃)₆³⁺. L'augmentation des signaux voltamétriques par rapport à l'électrode FTO nue dépendait fortement du type de sonde. L'accumulation des différentes sondes redox est attribuée à l'orientation verticale du nanocanal qui favorise le transport rapide et la diffusion à la surface de l'électrode. Une caractérisation électrochimique plus poussée a montré une interaction entre le processus contrôlé par la surface et le processus contrôlé par la diffusion, où les espèces adsorbées sont plus importantes dans les milieux dilués. Les résultats ont montré que la modification de la longueur debye et du rayon électrocinétique du nanocanal de silice en raison de la force ionique ou du diamètre du nanocanal affecte également le transport et la détection électrochimique de l'analyte paraquat. Les films de silice mésoporeuse ayant des tailles de pores différentes, préparés en utilisant différents bromure d'alkylammonium comme modèle, donnent des sensibilités différentes, qui pourraient être dues à la différence de charge électrochimique de la surface de la silice, ainsi qu'à la distribution des ions dans le nanocanal. Enfin, une tentative de modification de la surface de la paroi de silice en utilisant de la zircone a également été faite pour étudier le transport des cations, ce qui pourrait ouvrir la voie à une meilleure stabilité du film mésoporeuxOriented mesoporous silica-based film on FTO electrode was prepared via electrochemically-assisted self-assembly approach (EASA). A potential of -1.5V was applied to the FTO electrode containing a prehydrolyzed silica precursor, (e.g. tetraethyl orthosilicate), in the presence of a template (e.g. cetrimonium bromide) and electrolyte. This approach could generate vertically-aligned silica nanochannels with pore sizes adjustable between 2 and 3 nm, depending on the template. This work showed the voltammetric behavior and the selectivity of the mesoporous silica film towards various positively-charged cations of different nature, size, and charge. Results showed an accumulation and selectivity favoring the least positive charged ion: MB⁺ > PQ²⁺ > DQ²⁺ > Ru(bpy)₃²⁺ > Ru(NH₃)₆³⁺. The enhancement of the voltammetric signals relative to the bare FTO electrode was strongly dependent on the probe type. The accumulation of the different redox probe is attributed to the due to the vertical orientation of the nanochannel favoring fast transport and diffusion unto the electrode surface. Further electrochemical characterization showed an interplay of the suface-controlled and diffusion-controlled process, wherein adsorbed species is more prominent in diluted media. Results showed that changing the debye length and electrokinetic radius of the silica nanochannel due to the ionic strength or nanochannel diameter also affects the transport and electrochemical detection of the paraquat analyte. Mesoporous silica films having different pore size, prepared using different alkyl ammonium bromide as template, yield different sensitivities, which could be due to the difference in electrochemical charge of the silica surface, as well as the distribution of ions in the nanochannel. Finally, an attempt to modify the surface of silica wall using zirconia was also made to study the transport of cations, which could pave a way for an improved stability of the mesoporous film
2
Mazzotta, Z. "POSITRONIUM LASER EXCITATION IN THE AEGIS EXPERIMENT." Doctoral thesis, Università degli Studi di Milano, 2017. http://hdl.handle.net/2434/468556.
Abstract:
The AEgIS experimental program on antimatter systems involves the formation of antihydrogen
atoms for gravitational and CPT studies. One of the key ingredients of the
AEgIS strategy for the synthesis of antihydrogen atoms is the creation and manipulation
of Positronium (Ps) atoms laser excited to Rydberg states (n > 15).
In AEgIS, Ps is produced in bunched mode and the Rydberg excitation is achieved with
a two laser pulse technique, by passing through a n = 3 intermediate level. Because
excitation on Ps n = 3 state has never been proposed before, in AEgIS a dedicated experimental
apparatus and several detection strategies have been studied in order to observe
the first measurement ever on this interesting process. In this work we present and discuss
the experimental findings about the successful Ps n = 3 excitation.
Moreover, in this thesis, a study of the impact of involved nonlinear processes on the
excitation efficiency of a Doppler broadened atomic cloud is carried out. Presented simulation
results show that, by exploiting properly nonlinear processes in the generation of
the desired wavelength, it is possible to improve the excitation efficiency of a laser pulse.
It is crucial, in AEgIS, the use of a periodically poled crystal in quasi phase matching
regime. This gives a broadband continuous output spectrum whose wings survive to the
spectral cutting of the last nonlinear crystal of the chain (which has insufficient spectral
acceptance). This means that, at high laser energies, these wings can be amplified and
the spectrum gaps can be filled in, leading to high reachable saturation efficiencies. On
the contrary, in a laser pulse with a comb-shaped spectrum with a Gaussian envelope,
both wings and gaps drop rapidly to zero, and amplification hardly occurs at usually
employed energy regimes.
The presented model is finally used to fit AEgIS Ps n = 3 excitation experimental data.
3
SILVESTRI, ANTONIA. "Implantable Nanofluidic Membrane and Smart Electronic System for Drug Release Control." Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2918000.
4
Zhou, Jiandong. "Molecular simulation of aqueous electrolytes in silica nanochannels." 2002. http://etd.utk.edu/2002/ZhouJiandong.pdf.
Abstract:
Thesis (M.S.)--University of Tennessee, Knoxville, 2002.Title from title page screen (viewed on Oct. 8, 2002). Thesis advisor: Hank D. Cochran. Document formatted into pages (vii, 52 p. : ill. (some col.)). Vita. Includes bibliographical references (p. 47-49).
5
JHENG, HAO-YUAN, and 鄭皓元. "A study on Nanochannel fabrication method and experiments for single-crystal silicon substrate." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/13399233738067487926.
Abstract:
碩士國立臺灣科技大學
機械工程系
100
The paper applies Atomic Force Microscopy (AFM) to carry out machining of nanochannel groove on single-crystal silicon substrate. The paper innovatively proposes using the concept of specific down force energy (SDFE) to establish two machining methods of nanochannels in different shapes on single-crystal silicon substrate. For the first machining method of nanochannel groove proposed by the paper, machining is set to be carried out for one step first under a fixed down force in each machining level, and then a probe without offset carries out machining for repeated steps. In this way, the shape of the cross-section at the bottom after being machined by the probe without offset is similar to a semi-arc and -spherical shape. If the arc is greater, the bottom shape will be flatter. As to the second machining method of nanochannel groove, machining is set to be carried out for one step under a fixed down force in each machining level. After that, the probe is offset rightwards to carry out machining for one step, and then offset leftwards to move to the middle position between the abovementioned two steps to carry out machining. Completion of these steps is regarded as an offset cycle. Furthermore, using the concept of SDFE numerical value of step-by-step approximation fixed value, the depth of the middle step is calculated. In this way, between the shape of cross-section machined by the probe for two steps and the shape of cross-section machined after the probe has offset towards the middle, a protruding height is created. If the protruding height is greater than the convergence value (H=0.54nm) of the set protruding height, the offset amount would be increased, making the protruding height at its bottom converged to the set value. Using the second machining method of nanochannel groove, if the width of nanochannel groove is to be increased, the offset cycle has to be increased. In this way, the width of nanochannel groove would thus be increased. If machining of nanochannel is carried out on AFM machine, after the paper uses the first machining method of nanochannel groove and makes planning of nanochannel paths in different shapes, then T-shaped, orthogonal-shaped, Y-shaped and U-shaped nanochannels with depth of around 20nm can be machined. In the first machining method of nanochannel groove, since the probe does not have offset during machining, the machining of nanochannel is faster, and the depth is deeper. But in the second machining method of nanochannel groove, since the probe has offset during machining, the protruding part at the bottom has to be converged to be within the set range. Therefore, its experimental machining is slower than the first method, and the depth is also limited. However, if a special nanochannel with low depth value and high width value has to be used, the second machining method of nanochannel groove is a more ideal machining way, just like the protruding nanochannel machined by the paper. Since burrs appear at the edge of nanochannel after machining, the paper uses smaller down force, and then step by step increases down force at the edge of the nanochannel to carry out cutting so as to decrease the protruding height of burrs and make the protruding height of burrs at the edge converge to be within the range of 0.54nm as set by the paper. Finally, the paper carries out experimental machining of nanochannel groove on single-crystal silicon by AFM probe. After comparing the simulation results with the experimental results, the paper proves that these two machining methods are both feasible.
6
Chen, Po-Yen, and 陳博彥. "Theorectical study and experiment of nanochannel fabrication on single-crystal silicon wafer with specific dimension." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/05650224685205110718.
Abstract:
碩士國立臺灣科技大學
機械工程系
105
The paper uses offset cycle cutting method and derives equations of required cutting path and upward height at the bottom in the estimated offset cutting for cutting of trapezium groove to the expected depth and width on nanochannel, and establishes a method for cutting of trapezium groove to the expected depth and width. Since cutting depth would directly affect cutting width, the paper firstly determines the depth of groove, and then deals with the expected width of groove. Since the width of trapezium groove is associated with offset amount, the paper treats the probe as a sphere, and uses the cross-section of cutting path with the same groove depth, and its shape can serve as an intersecting circle. Therefore, using this principle, the paper derives a relational equation among offset amount, groove depth and groove width, and then substitutes the relational equation in the expected groove depth and width to obtain the required total offset amount of the probe. The paper divides total offset amount into different cutting paths, and then substitutes the cutting paths in the calculation equation of upward height at the bottom of the groove to achieve the upward height value at the bottom of the groove. The paper also suggests that the upward height value should converge at below the preset objective convergence value 0.54mm. If the upward height value at the bottom calculated from the cutting path of the estimated middle offset amount exceeds the objective convergence value, one more cutting path can be added again and again until the upward height value at the bottom of the trapezium groove at the cutting path of the estimated middle offset amount can converge at the objective convergence value. In general cutting of trapezium groove on nanochannel by atomic force microscopy (AFM), when cutting is conducted and it is getting close to the objective depth, down force is usually changed once to make the depth on the last layer close to the objective depth. Nevertheless, when down force is actually changed on AFM, the time for change of down force is around 7 minutes. Therefore, this method, requiring more time to change down force once more, is not considered a more efficient method. In order to achieve the least lead time of cutting during actual application, the paper proposes a cutting method requiring less cutting paths and less number of change of down force for cutting trapezium groove to the expected depth and width on nanochannel, as well as the objective function and constraints. First of all, the paper sets a safety factor of maximum down force for cutting by probe. With down force under the safety factor, simulation of cutting of a groove to a depth begins. Then down force is step by step adjusted, and cutting of trapezium groove to a cutting depth is simulated, making it gradually approximate to the objective depth of trapezium groove. After it is ascertained that the objective depth of trapezium groove is almost reached, this down force is set for the first cutting path on each cutting layer. In the second cutting path, down force is changed to achieve the same cutting depth as that in the first cutting path. Finally, specific down force energy (SDFE) theoretical model is applied to further estimate that the expected depth of trapezium groove on nanochannel can be achieved, and the least times for change of down force can be achieved. When the probe has cut the trapezium groove to the expected width, the abovementioned method for cutting to the expected width can be applied so as to cut the trapezium groove to the expected width. Furthermore, the required number of times of cutting path can be estimated, so that the number of times of cutting path can be less. In order to prevent the probe from being broken due to fatigue after cutting for multiple times, we have set a safety factor, and achieve the maximum down force under the safety factor. This down force is used to step by step adjust the down force size slowly in order to make it available to approximate to the expected depth at the down force. Nonetheless, for the expected cutting depth on the first cutting layer, the paper can use SDFE method to directly achieve the expected cutting depth. Thus, step by step approximation steps can be skipped over. As to cutting of the expected depth after cutting on the second cutting layer and the third cutting layer, SDFE equation cannot be directly used to estimate such depth. Therefore, during this time optimal step by step approximation method has to be employed to repeatedly simulate adjustment of down force and conduct cutting on the second cutting layer and cutting on the third cutting layer, so as to exactly approximate to the expected depth during cutting of trapezium groove depth on nanochannel at a set down force. After it is ascertained to have cut to the expected depth, the above method can be used again to adjust the offset amount, so as to cut the trapezium groove to the expected width. Focusing on different expected depths and widths of trapezium groove, the above method can also be used to simulate the down force that satisfies the needs of less number of times of cutting path and less number of change of down force.
7
Ma, Shih-Hung, and 馬士閎. "Estimation and verification of less cutting paths of nanochannel trapezium groove of single-crystal silicon." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/23989551439776662274.
Abstract:
碩士國立臺灣科技大學
機械工程系
104
Employing specific down force energy (SDFE) concept, the paper establishes two methods for estimating the least cutting paths of target convergence function for optimal successive approximation of the expected depth of nanochannel trapezium groove. The first method is three-cutting-path offset cycle cutting method. Each path of cutting is made at a fixed down force. Furthermore, the least cutting paths to achieve the expected depth of nanochannel trapezium groove can be estimated. The second method is two-cutting-path offset cycle cutting method. For this method, the first cutting path of each cutting layer is set to use a fixed down force. In the second path, down force is changed to achieve the same cutting depth as in the first cutting path. When down force is to be changed on the AFM apparatus, additional effort and time have to be spent for such change of down force. In order to achieve the least fabricating lead time in practical application, SDFE theoretical model is adopted to further find out the estimation method that estimates the least cutting paths to achieve the expected depth of nanochannel trapezium groove. Not only the least cutting paths are estimated, the number of times for change of down force is also decreased to the least, making the fabricating lead time decreased to the least as well. First of all, the paper uses three-cutting-path offset cycle cutting method to fabricate nanochannel trapezium groove of single-crystal silicon (Si) substrate. It is set that cutting is made for one path at a fixed down force on each cutting layer. After that, the probe is offset rightwards for cutting for one more path, and then offset leftwards to the middle position between the previous two cutting paths for cutting. During this time the offset amount should meet the condition that the upward and downward values of the nanochannel trapezium groove have to be within the set range of convergence values. Then this is considered an offset cycle cutting. If it is required to increase the width of nanochannel groove, the number of offset cycles has to be increased. In this way, the width of nanochannel groove can be increased. But this method uses a smaller down force and the depth is limited, so that when offset cycle cutting is carried out at the very beginning, offset amount adjustment should be a prioritized task to achieve a better upward value. If the upward height at the bottom of nanochannel trapezium groove is still greater than the set convergence value of upward height, offset amount should be adjusted repeatedly until the bulge height at the bottom is converged as below the set value. The paper uses three-cutting-path offset cycle cutting method for cutting, and establishes an estimation method of the least cutting paths of target convergence function for optimal successive approximation of the expected depth of nanochannel trapezium groove. The study repeatedly adjusts the down force and offset amount until a suitable down force and the least cutting paths are found to achieve the expected depth of nanochannel trapezium groove. The estimated results are compared with the actual experimental results for verification. The paper also adopts two-cutting-path offset cycle cutting method to fabricate nanochannel trapezium groove of single-crystal Si substrate. The paper firstly sets a fixed down force for the first cutting path on each cutting layer, and then changes the down force in the second cutting path, making it achieve the same cutting depth as in the first cutting path. In the simulation process, it is found that in the two-path offset cycle cutting method, if the same cutting depth for the two cutting paths is arbitrarily adjusted, a fixed offset amount can be used to achieve the fixed upward height at the bottom of nanochannel trapezium groove. Therefore, the paper proposes using a greater down force to achieve a upward height that is smaller than the set convergence value, and establishes an estimation method of the least cutting paths and the shortest fabricating lead time to achieve the expected depth of nanochannel trapezium groove. In order to avoid damage of probe caused during cutting for multiple paths, the paper firstly sets a greater down force value to be acquired under a safe cutting coefficient of down force of probe, to conduct cutting of nanochannel. The paper firstly sets a fixed down force for the first cutting path on each cutting layer, and then changes the down force for the second cutting path, making it achieve the same cutting depth as in the first cutting path. On the layer before achieving the expected depth of nanochannel trapezium groove, the paper changes the down force for the first cutting path on the last layer, and further achieves the expected depth of the machined nanochannel trapezium groove. However, when down force is to be changed on the AFM apparatus, the time for setting of down force is additionally consumed. In order to use less fabricating lead time to achieve the expected depth of the cut nanochannel trapezium groove, the paper has to decrease the number of times for change of down force. Through simulation of the change of offset amount, the upward height at the bottom of nanochannel trapezium groove becomes smaller than the set convergence value, and then down force is adjusted repeatedly. After calculation, for the first cutting path from the first cutting layer to the last cutting layer, the depth can be gradually deepened at a fixed down force. In the first cutting path on the last cutting layer, the expected depth of the cutting nanochannel trapezium groove can be achieved. In the above steps, the down force for the second cutting path on each cutting layer is changed, making the cutting depth the same as the one in the first cutting path. This method can decrease the fabricating lead time for down force adjustment by one time. Through repeated adjustment of down force, the paper finally can use suitable down force, the least cutting paths and the least fabricating lead time to achieve he expected depth of nanochannel trapezium groove. The paper also compares the estimated results with the actual experimental results for verification.
8
Fang, Xin-Ren, and 方信人. "Establishment and experimental verification of simulation model of single-crystal silicon nanochannel curve machining to the preset width and depth." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/43t72z.
Abstract:
碩士國立臺灣科技大學
機械工程系
106
The paper proposes a simulation model for nanochannel curve machining to the preset width and depth. First of all, the paper uses a Cubic Spline curve equation acquired from the self-set control points .This study uses the obtained cubic spline curve equation to further calculate the multiple integers’ tiny line segments of a near-curve, and conducts AFM for machining a nanochannel which is a straight-line segment and a curve segment machining experiments. The paper firstly uses the method of machining a straight-line trapezium groove to the preset depth and width, and then calculates the offset amount and the number of cutting passes required for machining the straight-line trapezium groove up to the preset depth and width. The paper also uses the self-set control points to obtain the curve equation of the path for machining. Besides, the paper innovatively proposes using the control point set by the first curve, and then uses offset equation and the offset amount obtained above to find a method for calculating the control point of curve equation of other passes on the same cutting layer. Furthermore, the paper calculates the curve equation of other passes on the same cutting layer. Since the AFM machine is unable to carry out curve machining, the paper proposess applying the calculation equation of the chord error between curves and tiny line segments, and further using straight-lined near-curve method to calculate the near-curve straight line formed by connection of many tiny line segments. But the accuracy of AFM machine is 1nm only, so the various intersecting points of the tiny line segments are taken as integers to carry out machining. In order to reduce the error, we take, when carrying out measurement, the cross-section at a nearly ideal curve position for measurement. Finally, the paper carries out comparison between simulation results and experimental results of the simulation model of the self-established curve machining up to the preset width and depth. It is proved that the simulation model established by the paper is reasonable and acceptable. When carrying out, in general, cutting of an nanochannel straight-line segment trapezium groove, by AFM machine it is usually found that as it is getting close to the target depth, down force has to be changed for one more time so as to make the depth of the last cutting layer approach to the target depth. Nonetheless, since the time required for the AFM machine to actually carry out change of down force is around 7 minutes, this method needs to spend more time for change of down force for one more time. In order to achieve the least preparation time for machining during application to experiments, the paper uses the machining of nanochannel straight-line segment trapezium groove up to the preset depth and width, which is a machining method requiring less cutting passes and less times of change of down force, as well as its target function and constraints. At the beginning, the paper firstly sets the safety coefficient of the greatest down force for probe cutting, and starts simulated cutting of the depth of trapezium groove at the down force under safety coefficient. After that, the paper step by step adjusts the down force and simulates cutting of the cutting depth of trapezium groove, making it step by step approach to the target depth of trapezium groove. After the paper confirms that it is close to the target depth of trapezium groove, the paper sets the down force value for the first cutting pass on each cutting layer. For the second cutting pass, down force is to be changed to acquire the same cutting depth as that of the first cutting pass. Finally, specific down force energy (SDFE) theoretical model is applied to further estimate the number of cutting layer and the down force of the first cutting pass of the achievable preset depth of the nanochannel straight-line segment trapezium groove. Furthermore, the least number of times of change of down force can be achieved. Here, in order to prevent occurrence of broken probe due to probe fatigue after cutting for multiple times, safety coefficient is set to achieve the greatest down force under the safety coefficient. The paper also uses this down force to step by step adjust the down force size slowly, and makes cutting by the down force approach to the preset depth. Nevertheless, for the preset cutting depth on the first cutting layer, SDFE method can be used to directly obtain the preset cutting depth. Thus, the procedures of stepwise approach can be neglected. As to cut to the preset depth after cutting on the second cutting layer and the third cutting layer, SDFE equation cannot be directly used to estimate this depth. Hence, optimal stepwise approach method has to be used to repeatedly simulate and adjust the down force for carrying out cutting on the second cutting layer or cutting on the third cutting layer in order to make the depth of straight-line segment trapezium groove of the nanochannel cutted by the set down force, exactly approach to the preset depth. After cutting to the preset depth is confirmed, the above method is used to adjust the offset amount to achieve the preset width of the cutted straight-line segment trapezium groove. The paper proposes integration of straight-line segment machining and curve machining of nanochannel trapezium groove to different preset depths and widths. In accordance with the above method, the paper firstly simulates the better down force that satisfies less cutting passes and less times of change of down force for various cutting passes on different cutting layers of straight-line segments. The acquired better down force is further applied to the integrated straight-line segment machining and curve machining of nanochannel trapezium groove.
9
Lin, Chien-ting, and 林建廷. "A study on simulation model establishment and experiment for cutting of nanochannel groove on single-crystal silicon with application of specific down force energy (SDFE) and changed down force." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/72661083716068969533.
Abstract:
碩士國立臺灣科技大學
機械工程系
101
The paper innovatively proposes a concept that the specific down force energy (SDFE) values of different axles are supposed to be almost the same fixed value. According to the SDFE theoretical model of different axles and the nanomachining depth and shape of cutting tool both already known, the paper derives the theoretical equations for estimation of down force and cutting force for nanomachining of V-shaped groove on single-crystal silicon (Si) workpiece. The paper firstly conducts an experiment of machining of nanoscale V-shaped groove by probe. From the experiment, the SDFE for nanocutting of single-crystal Si is found. It is then compared with the down force and cutting force acquired from simulation using the simulation model of three-dimensional quasi-steady molecular statics, and then proves it feasible to use the SDFE theoretical equation of different axles proposed by the paper to estimate the cutting force and down force for cutting of nanoscale V-shaped groove on single-crystal Si. The paper also uses offset cycle machining method to perform machining of nanochannel trapezium groove on single-crystal Si substrate. Machining is set to be carried out for one pass on each machining layer at a fixed down force. After that, the probe is offset rightwards to carry out machining for one more pass, and then leftwards to the middle position between the above two passes, finishing an offset cycle. If the width of nanochannel groove is to be increased, the number of offset cycles has to be increased. By doing so, the width of nanochannel groove can be increased. However, since a smaller down force is used in this method, groove depth is limited. Therefore, the paper additionally makes an innovative proposal of an offset machining method with a changed down force. For this method, after machining by offset cycle method, the numerical value of downward indentation at the bottom is firstly controlled to be within the range set by the paper. Then the concept of fixed down press depth is used to reversely infer the down force, and the excessively great bulgy height at the bottom can be removed. If a greater down force is used, a deeper groove can be obtained. However, due to greater bulgy height at the bottom, the probe is offset to the upward bulging position at the bottom, and the machining depth is controlled to be the same as the depth of the middle pass. Furthermore, down force is reversely inferred. Using the down force acquired from the reversely inferred down force, the upward bulginess on the 1st layer is removed. If the bulgy height at the bottom is still greater than the set convergence value of bulgy height, reverse inference method of down force can be used again. The probe is offset to the upward bulging position at the bottom, and machining is carried out at the changed down force reversely inferred again at the upward bulging position of the bottom. The above step is repeated until the bulgy height at the bottom converges to be below the set value. With offset machining method at the changed down force of the inversely inferred down force, the paper firstly simulates machining of straight-line nanochannel trapezium groove on single-crystal si, and proves the simulation by experiment. Besides, the paper makes path planning for nanochannels in different shapes and simulates machining of a trumpet-shaped opening combining with a straight-line nanochannel trapezium groove with at the depth of 10nm~20nm on single-crystal Si substrate and a Y-shaped combining with U-shaped nanochannels, and proves the simulation by experiment. For the offset cycle machining method of nanochannel groove at a fixed down force, since only a smaller down force can be used, groove depth is limited, and machining can be undergone for a depth of around 10nm only. Besides, machining of nanochannel takes a longer time and needs more machining passes. Using offset machining method with changed down force for machining of nanochannel trapezium groove can acquire a deeper depth rapidly. The paper also uses the SDFE theoretical equation of different axles to estimate the down force and cutting force for the offset cycle method at a fixed down force and the offset cycle machining method at a changed down force. As to machining of the various nanochannels mentioned above, since there is bulging burr appeared at the edge of nanochannel after machining. The paper uses a smaller down force, and then step by step increases down force to carry out cutting of nanochannel edge, and makes the bulgy height of burr at the edge converge to be within the range set by the paper. Finally, the paper conducts a machining experiment of nanochannel trapezium groove on single-crystal Si by atomic force microscopy (AFM) probe, and simulates the abovementioned offset cycle machining method at a fixed down force and the offset machining method at a changed down force. The simulation results of nanochannel trapezium groove on single-crystal Si are compared with the experimental results, proving that these two machining methods are both feasible.
10
Lu, Chang-Hung, and 呂昶宏. "Analysis of machining force and temperature field for fabricating single-crystal silicon trapezium groove by offset cutting method and analysis of downward depth at the junction of T-shaped nanochannel." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/4zc7wu.
Abstract:
碩士國立臺灣科技大學
機械工程系
104
The paper applies offset cutting method to fabricate single-crystal silicon trapezium groove at a fixed cutting depth. Cutting of 1st cutting path is carried out on each cutting layer at a fixed cutting depth, then cutting of the 2nd cutting path is carried out by making rightward offset the cutting tool, thus competing a offset cutting cycle. If it is required to broaden the width of trapezium groove, rightward offset the cutting tool can be made for cutting to complete cutting of the 3rd cutting path. Using the above method, the number of cutting layers can be increased, and their cutting width and cutting depth can thus be increased as well. The paper also applies the equations for estimating cutting force and down force, both established by specific down force energy (SDFE) concept, and simulates the down force and cutting force for the 1st cutting path during offset cutting of trapezium groove on the 1st cutting layer, as well as those for rightward offset cutting of the 2nd cutting path. First of all, considering a smaller size probe, SDFE equation is used to calculate the cutting force and down force for such offset cutting method at a fixed cutting depth in this paper. After that, three-dimensional quasi-steady molecular statics nanocuting simulation model is used to simulate acquisition of down forces and cutting forces in the 1st and 2nd cutting paths using offset cutting method for cutting on the 1st cutting layer by the same smaller sized probe and cutting depth. Comparison is made between the cutting forces and down forces obtained from the above mentioned two methods, in order to prove the rationality of using SDFE equation to acquire cutting force and down force of offset cutting method. The three-dimensional quasi-steady molecular statics nanocuting simulation model not only calculates the down force and cutting force of each cutting path at a fixed cutting depth, but also calculates equivalent stress and equivalent strain, as well as the increased temperature of the cutted single-crystal silicon workpiece. The paper further analyzes the temperature distribution of the cutted single-crystal silicon workpiece. Besides, the paper explores the T-shaped nanochannel at a cutting depth of around 20nm at a fixed down force. This paper proposes employing SDFE concept at the junction between horizontal cutting path and vertical cutting path, using the same fixed down force in the middle of horizontal cutting path, and downpressing and cutting the workpiece material in the direction of vertical cutting path. SDFE method and CAD software are used to simulate the removing volume, thus forming a depressed shape with a depressed depth. SDFE equation and CAD software are used to simulate the cutting and cutting depth of each horizontal cutting layer and the depressed depths at the junction of T-shaped nanochannels on different horizontal cutting layers. As observed from the simulation results, the cutting depth at the junction between horizontal cutting layer and vertical cutting layer of T-shaped nanochannel is almost equivalent to an increased cutting depth on an additional horizontal cutting layer. The paper also compares the experimental results and simulation results of the depressed depths measured at the junction of T-shaped nanochannel being cutted up to the 5th cutting layer. Hence, the paper’s proposal of using SDFE method to simulate and estimate the depressed depth produced at the junction between horizontal and vertical cutting paths on each cutting layer of T-shaped nanochannel, is proved to be feasible.
Book chapters on the topic "Silica nanochannel":
1
Hibara, Akihide, Takumi Saito, Haeng-Boo Kim, Manabu Tokeshi, Takeshi Ooi, Masayuki Nakao, and Takehiko Kitamori. "Nanochannel on Fused-Silica Microchip and Liquid Properties Investigation by Time-Resolved Fluorescence Measurements." In Micro Total Analysis Systems 2002, 769–71. Dordrecht: Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-010-0504-3_56.
2
Duan, Chuanhua. "Enhanced Ion Transport in 2-nm Silica Nanochannels." In Transport and Reactivity of Solutions in Confined Hydrosystems, 83–93. Dordrecht: Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-7534-3_7.
3
Tas, Niels, Nataliya Brunets, Joost W. van Honschoten, Jeroen Haneveld, and Henri V. Jansen. "Static and Dynamic Capillarity in Silicon Based Nanochannels." In Transport and Reactivity of Solutions in Confined Hydrosystems, 29–41. Dordrecht: Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-7534-3_3.
4
Naik, Sajo, and Igor Sokolov. "Ultrabright Fluorescent Silica Particles: Physical Entrapment of Fluorescent Dye Rhodamine 640 in Nanochannels." In ACS Symposium Series, 214–24. Washington, DC: American Chemical Society, 2008. http://dx.doi.org/10.1021/bk-2008-0996.ch016.
5
Honschoten, Joost, Nataliya Brunets, and Niels Tas. "Capillary Action in Silicon-Based Nanochannels." In Nanoscale Liquid Interfaces. Pan Stanford Publishing, 2013. http://dx.doi.org/10.1201/b14789-12.
6
"Free Radical Attack on C60 Embedded in Nanochannels of Mesoporous Silica." In Nano Science and Technology, 154–59. CRC Press, 2003. http://dx.doi.org/10.1201/9780203390283-19.
7
Lin, T., H. Lin, C. Lee, and C. Mou. "Free Radical Attack on C60 Embedded in Nanochannels of Mesoporous Silica." In Nano Science and Technology, 142–47. CRC Press, 2003. http://dx.doi.org/10.1201/9780203390283.ch15.
8
Yeh, Yi-Qi, Gui-Min Teo, Bi-Chang Chen, Hong-Ping Lin, Chih-Yuan Tang, and Chin-Yen Lin. "A study on the synthesis of mesoporous silica and carbon platelets with perpendicular nanochannels." In Recent Progress in Mesostructured Materials - Proceedings of the 5th International Mesostructured Materials Symposium (IMMS2006), Shanghai, P.R. China, August 5-7, 2006, 389–92. Elsevier, 2007. http://dx.doi.org/10.1016/s0167-2991(07)80342-9.
Conference papers on the topic "Silica nanochannel":
1
Ziemys, Arturas, Alessandro Grattoni, Jaskaran Gill, and Mauro Ferrari. "Silica Nanochannel Surface Effect on Monosaccharide Transport." In ASME 2010 First Global Congress on NanoEngineering for Medicine and Biology. ASMEDC, 2010. http://dx.doi.org/10.1115/nemb2010-13216.
Abstract:
The interface of silica nanochannel of 10 nm was studied by molecular modeling and experimental methods. Molecular Dynamics study on glucose solution revealed that 2–3 nm of interface solution to silica walls has reduced glucose diffusivity. That reduction affects the effective diffusivity of glucose in silica nanochannel. Experimental results show Fickian-like release of glucose through 13 nm nanochannel. Molecular modeling and experimental results suggest that glucose is not sufficiently confined to possess non-Fickian behavior.
2
Duan, Chuanhua, Yu-Feng Chen, Dong-Kwon Kim, and Arun Majumdar. "Detection of Non-Diffusion-Limited Enzymatic Surface Reaction in Nanofluidic Channels." In ASME 2009 7th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2009. http://dx.doi.org/10.1115/icnmm2009-82188.
Abstract:
Using nanofluidic channels to detect enzymatic surface reactions can overcome diffusion-limited patterning as enzyme accelerates surface reactions without being consumed. In this paper, Trypsin proteolysis reaction is used to demonstrate this idea. Trypsin (enzyme) cleaves Poly-L-Lysine (PLL) coated on the surface of silica nanochannels, resulting in a change of surface charge density and channel height. This change is detected by monitoring the electrical conductance along the nanochannels. 50 μg/ml Trypsin has been detected in 90 nm-height nanochannels within one hour, which is 30 times faster compared to that of a diffusion-limited surface binding reaction. The effect of nanochannel height and the detection limitation are also discussed. Our results indicate that nanofluidic channels can be used for detecting enzymatic-based surface reactions.
3
Li, Deyu, Min Yue, Rohit Karnik, Arun Majumdar, Rong Fan, and Peidong Yang. "Ion Transport in Nanochannels." In ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56717.
Abstract:
Two kinds of nanochannels have been fabricated and ion transport in these nanochannels has been measured. Silica nanotube arrays have been fabricated from Si nanowire templates. The silica nanotubes can be more than 20 μm long with an inner diameter from 10 to 200 nm. A nanofluidic device based on individual silica nanotubes has been fabricated by placing the nanotube on a glass substrate and patterning with respect to individual nanotubes. A similar nanofluidic device with SiNx as the channel wall material has also been fabricated. The cross-section of the SiNx nanochannel is 40 nm high and 1 μm wide, while the channel length extends up to more than 24 μm. Ion transport though these nanochannels has been studied with different concentration KCl solutions to investigate the effects of electric double layer thickness on ion transport. Results show that for high concentration solutions, the measured current fit the theoretical prediction based on the bulk concentration. However, for low concentration solutions, the measured current was larger than that calculated with the bulk concentration, indicating that for low concentration solutions, the ion concentration within the channel was decided not only by the bulk solutions, but also by the surface charge density.
4
Karnik, Rohit, Kenneth Castelino, Chuanhua Duan, Rong Fan, Peidong Yang, and Arun Majumdar. "Nanofluidic Devices for Sensing and Flow Control." In ASME 4th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2006. http://dx.doi.org/10.1115/icnmm2006-96156.
Abstract:
Nanofluidics is concerned with fluidic channels that are typically 1–100 nm in size. We have fabricated nanofluidic devices using both 1-D silica nanotubes and 2-D nanochannels to explore transport phenomena at the nanoscale. Here we review our work on 2-D nanochannels that provide confinement in one dimension. Our work mainly deals with two aspects of nanofluidics (a) effects related to electrostatic interactions and (b) effects related to biomolecule size. Surface charge plays an important role in nanofluidic channels, when the channel size is comparable to the Debye length. Using both electrical conductance measurements and fluorescence imaging, we studied the effects of surface charge in our nanofluidic devices, and demonstrated that the environment in nanochannels is governed by surface charge. We modified the nanochannel surface and showed that these modifications can be sensed by measuring ionic conductance of the nanochannels. Further, binding reactions involving biomolecules can be sensed at both low and high ionic concentrations. Our results showed that at low concentrations, conductance is governed by biomolecule charge, while at high concentrations it is governed by biomolecule size. Based on electrostatic effects in nanochannels, we also developed a nanofluidic transistor for flow control. This metal-oxide-solution field effect transistor was fabricated by patterning a metal gate electrode over nanochannels, similar to a MOSFET. Just as the gate voltage of a MOSFET controls carrier concentration in the semiconductor, we demonstrated that the gate voltage in a nanofluidic transistor controls the concentration of ions and biomolecules in the nanochannel, and hence controls their transport. Our fabrication process uses standard lithography, and is amenable to making networks of nanochannels. It suggests that rationally designed nanofluidic networks could be developed using this process for applications in sample preparation, sensing and switching. We are currently studying flow control and switching using field-effect, as well as ionic transport using patterned surface charge in nanofluidic devices.
5
Sang Young Lee, Sang Youl Yoon, Kyeong-Hwan Lee, and Sung Yang. "Silica nanochannel device for pH sensing based on surface charge density changes." In 2010 IEEE 10th Conference on Nanotechnology (IEEE-NANO). IEEE, 2010. http://dx.doi.org/10.1109/nano.2010.5697939.
6
Suciu, Claudiu Valentin. "Entropy-Based Design of Liquid-Repellent Nanochannels Destined to Energy Absorption Systems (EAS)." In ASME 2009 7th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2009. http://dx.doi.org/10.1115/icnmm2009-82005.
Abstract:
Entropy production is a key parameter to evaluate the maximal efficiency of engineering systems. Recently, liquid penetration/exudation in/from non-wetted nanoporous solids was employed to develop ecological energy absorption systems (EAS). Dissipation is based on the well-known fact that external work must be done to spread a liquid on a lyophobic surface. Minimization of the entropy production is usually required to obtain high-efficiency engineering systems. However, enhancement of the EAS nano-damping ability requires oppositely maximization of the entropy generated through interfacial, frictional and thermal instabilities. A model of the entropy production during water flow inside of a liquid-repellent silica nanopore is proposed. A mixture of hydrophobized nanoporous silica and water is introduced inside of a compression-decompression chamber. Using a thermo-camera, the temperature distribution on the external surface of the test chamber is recorded versus the working time and the positions of main heat sources are identified. Such experiments allow determination of the overall dissipation, generated heat, and the heat flux at the wall of silica nanochannel. Then, the test rig is introduced inside of an incubator that allows temperature adjustment in the range 0∼50 °C and the thermal effects on the hysteresis and damping performances are evaluated. From such tests one determines the variation of the solid surface tension on the nanochannel wall versus temperature. Entropy (heat) production in the nanochannel is estimated and compared with experimental data to validate the proposed model.
7
Kim, Dong-Kwon, Chuanhua Duan, Yu-Feng Chen, and Arun Majumdar. "Power Generation From Concentration Gradient by Reverse Electrodialysis in Ion Selective Nanochannel." In ASME 2009 7th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2009. http://dx.doi.org/10.1115/icnmm2009-82208.
Abstract:
In this article, ion selective nanochannels are studied to generate electric power from concentration gradient by reverse electrodialysis. When nanochannels bring into contact with aqueous solution, the surface of nanochannels acquires charges from ionization, ion adsorption, and ion dissolution. These surface charges draw counter-ions toward the surface and repel co-ions away. Therefore, when an electrolyte concentration gradient is applied to nanochannels, counter-ions are transported through nanochannels much more easily than co-ions, which results in a net charge migration of ions. Gibbs free energy of mixing, which forces ion diffusion, thus can be converted into electrical energy by using ion-selective nanochannels. Silica nanochannels with heights of 26 nm and 80 nm fabricated by glass-silicon anodic bonding were used in this study. We experimentally investigated the power generation from these nanochannels placed between two potassium chloride solutions with various combinations of concentrations. The power generation per unit channel volume increases when the concentration gradient increases, while it decreases as channel height decreases. The highest power density measured is 26 kW/m3. Our data also indicates that the efficiency of energy conversion and the ion selectivity increase with a decrease of concentrations and channel height. The best efficiency obtained is 24%. Compared with ion-selective membranes, nanochannels promise more reliable operation since they are readily compatible with standard CMOS process and do not shrink and swell in response to their environment. Power generation from concentration gradient in ion selective nanochannels could be used in a variety of applications, including micro batteries and micro power generators.
8
Pennathur, Sumita, Fabio Baldessari, Mike Kattah, Paul J. Utz, and Juan G. Santiago. "Electrophoresis in Nanochannels." In ASME 2006 2nd Joint U.S.-European Fluids Engineering Summer Meeting Collocated With the 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/fedsm2006-98558.
Abstract:
Micro- and nanofabrication technology enables the application of electrokinetics as a method of performing chemical analyses and achieving liquid pumping in electronically-controlled microchip systems with no moving parts. We are studying and leveraging the unique separation modalities offered by nanoscale electrokinetic channels. We report analytical, numerical, and experimental investigations of nanochannel electrophoretic transport and separation dynamics of neutral and charged analytes. Our study includes continuum-theory-based analytical and numerical studies of nanofluidic electrophoretic separation dynamics, as well as experimental validation of these models. We have used 40, 100, and 1,560 nm deep channels etched in fused silica to independently measure mobility and valence of small ions. We also use these devices to separate 10 to 100 base pair DNA in the absence of a gel separation matrix. The effective free-solution mobilities of the ds-DNA oligonucleotides measured in 1560 nm deep channel are consistent with reported literature values, while smaller values of the mobility were measured for 4o nm deep channels for the same charge-species. The goal of our work is to explore and exploit electrokinetic flow regimes with extreme scales of length and charge density.
9
Duan, Chuanhua, and Arun Majumdar. "Ion Transport in 2-NM Nanochannels." In ASME 2009 7th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2009. http://dx.doi.org/10.1115/icnmm2009-82190.
Abstract:
In this paper, we report ion transport in 2-nm-deep nanochannels. These nanochannels are formed by controlled dry etching in silicon wafer and following anodic bonding with pyrex substrate. Our results show that surface charge dominates ion transport in these channels at concentration up to 100 mM. Due to geometry confinement effect, these nanochannel take ultra long time to reach a steady state, 3 or 4 magnitude longer than bulk diffusion. Conductance data at different ionic concentrations are compared with simulation results from a one dimensional model that accounts for salt & pH-dependent surface charge. Difference between model and experimental data indicates that proton mobility at low concentration is one magnitude higher than bulk mobility while Na+/K+ mobility doens’t change at this length scale.
10
Nguyen, Nam-Trung, and Patrick Abgrall. "Fabrication of Nanochannels in Silicon and Polymers." In ASME 2008 First International Conference on Micro/Nanoscale Heat Transfer. ASMEDC, 2008. http://dx.doi.org/10.1115/mnht2008-52063.
Abstract:
This paper reports the fabrication of planar nanochannels in silicon and thermoplastic. Conventional technologies such as reactive ion etching (RIE) and anodic bonding were used for fabricating the silicon-based nanochannels, while hot embossing and thermal bonding were used for polymer-based nanochannels. Due to the limit of photolithography, the lateral dimension of the channels are kept on the order of micrometers. The depth can be controlled precisely by etch rate or deposition rate. While fabrication technologies for nanochannels in silicon and glass are established and straightforward to implement, fabrication of planar nanochannels in a plastic is challenging because of the more severe collapsing of the structure during bonding. Besides the silicon technology, we demonstrate a simple and low-cost fabrication technology of planar nanochannels by hot-embossing in a thermoplastic and bonding below the glass transition temperature.