Spin Speed Research Articles

Optimization of Graphene infused Natural Rubber Sensing Film and Polydimethylsiloxane for Flexible Pressure Sensor

A flexible and stretchable pressure sensor offers significant benefits in human-computer interaction, healthcare, and tactile sensing in robots. We present a novel study optimising Polydimethylsiloxane (PDMS) and graphene-infused unvulcanised natural rubber sensing film to increase sensor sensitivity and dielectric permittivity. By optimising the PDMS thickness uniformity, NR-G film’s impedance and capacitance-pressure loading response, it is possible to enhance the pressure sensor's sensitivity across a wide pressure range, covering human finger motion. With our synthesized homogenous 5wt% of NRG composite, a capacitance value of 193pF was achieved when applying pressure of 150 kPa at a frequency of 0.5 Hz. Excellent sensitivity and dielectric permittivity of 0.020 kPa-1 and 109.1, respectively, which is ~ 6.5 folds higher than pure NR. PDMS thickness of 300μm with ±3% uniformity was achieved using 90s spin time and 200rpm spin speed. This optimisation of sensing material and substrate is important in developing wearable sensors having applications in soft robotics, health monitoring electronics, and soft human-machine interfaces.

Experimental research and numerical simulation of the relationship between yarn tension and multi-balloon shape

Yarn tension during ring spinning is influenced by the shape of the balloon. With the high speed of ring spinning, the existing balloon control technology will have problems with yarn breakage caused by increased tension and yarn wear during the spinning process. Therefore, this article takes the naturally formed multi-balloon as the research object and analyzes the force of the yarn in the balloon section to establish the mathematical model of the steady-state balloon section. Then we selected the appropriate parameters to compare the balloon trajectory graph obtained by simulation and experiment, to verify the validity of the mathematical model. Finally, the relationship between the yarn tension and the number of balloon segments under different balloon heights and spindle speeds, and the conditions for the stable shape of multi-balloon are discussed. It was found that under different balloon shapes, increasing the number of balloon segments can effectively reduce the yarn tension at the yarn guide, and the stable conditions of balloons with different numbers of segments under certain process conditions. The findings are of great significance to the subsequent research on the technological parameters of low-tension spinning and the structural design of ring-spinning machines.

Cross polarization from dipolar-order under magic angle spinning: The ADRF-CPMAS NMR experiment

Techniques for enhancing the signals arising from low-γ, insensitive (I) nuclei are central to solid-state nuclear magnetic resonance. One of the leading and best-established methods to sensitize these unreceptive species is Hartmann–Hahn cross polarization (HH-CP), a polarization transfer mechanism often executed under MAS. Herein, we explore the possibility of utilizing the 1H dipolar order created via adiabatic demagnetization in the rotating frame (ADRF), to enhance the unreceptive spins under MAS. It is found that an efficient polarization transfer via ADRF-CPMAS is not only possible but can exceed, at least in some instances involving plastic crystals, the efficiency of an optimized HH-CPMAS transfer. The experiment requires low radiofrequency nutation fields on both the 1H- and the I-spin channels, and displays unusual matching conditions that are reminiscent of the zero- and double-quantum matching conditions arising under CPMAS, albeit centered at zero frequency and demanding the simultaneous involvement of several spins. The origin of these multi-spin transfer processes is analytically derived and numerically simulated in predictions that compare well with experimental 13C and 15N results collected on model compounds at different spinning speeds. These derivations start from descriptions that depart from traditional thermodynamic arguments, and treat instead the ADRF processes in static and spinning solids on the basis of coherent evolutions. The predictions of these analytical derivations are corroborated by numerical simulations. The effects of additional factors, including chemical shift anisotropies, J-couplings, and radiofrequency inhomogeneities, are also theoretically and experimentally explored.

ZnONR Microstructure Modification and their Potential for High Reversibillity Performance of AC-Mn<sub>2</sub>O<sub>3</sub> Supercapacitor

One of Indonesia's most significant issues with technological growth is the lack of electrical energy storage devices. Active materials have low electrical conductivity, accessibility, and ion diffusion. Therefore, it is urgently required to study the combination of higher electrical conductivity ZnO and high surface area of AC-Mn2O3. However, ZnO nanorods (ZnONR) can be modified from ZnO nanoparticles (ZnONP). The structure modification may increase energy density due to having a higher surface area than ZnONP. Three different electrodes with AC-Mn2O3 addition various spin coated of 1000 rpm (MZnONR1), 2500 rpm (MZnONR2), and 3000 rpm (MZnONR3). The electrodes were then packaged in a sandwich flat symmetric supercapacitor. The characterization was carried out using X-RD, SEM-EDX cross-section, FTIR, and Cyclic Voltammetric. It is obtained that the highest specific capacitance showed by symmetric supercapacitor MZnONR1 with low speed of spin coating. We also found that the greater the deposited ZnNR content, the lowest thickness until 43.76 μm, the crystallinity until 62% and the highest porosity until 79%. This shows that the MZnONR1 sample exhibits the best electrochemical performance, which is supported by its morphological properties. It is shown that the higher the Zn content, the stability performance AC-Mn2O3 supercapacitor higher. ZnONR1 sandwich flat symmetric supercapacitor have a specific capacitance 0.0086 Fg-1 with an 0.00433 Whg-1 energy density. Furthermore, it was found that the addition of the AC-Mn2O3 increased 2800x compared to the ZnONR1, which reached 28.04 Fg-1 and an 14.09 Whg-1 of capacitance specific and energy density, respectively.

Preparation of PAN@PU coaxial electrostatic spun nanofibers for oil/water separation

AbstractCoaxial electrostatic spinning (co‐electrostatic spinning) technology has greatly expanded the versatility of the preparation of core–shell polymer nanofibers and has found a wide range of applications in the environmental and biological fields. Here we present a method for the preparation of coaxial nanofibers using polyacrylonitrile (PAN) and polyurethane (PU) as raw materials. It was found that the tensile strength ranges from 2.14 to 4.07 MPa with the increasing spinning speed of the nucleated PU layer, and the elongation at break was up to 95.09% for M6:4, which was three times higher than that of the original MPAN (30.54%), and the toughness of the nanofiber film was also significantly improved. Finally, the oil/water separation capacity of the coaxial nanofiber membrane was investigated, and the results showed that the separation fluxes for various oil compounds ranged from 2380.18 to 3130.17 L·m−2·h−1, with separation efficiencies above 99%. This study not only investigates the effect of different flow rates of core (PU)/shell (PAN) on the performance of coaxial electrostatic spun nanofiber membranes, but also provides a new insight into the coaxial electrostatic spinning process.

Optical enhancement in perovskite thin films using moth-eye anti-reflection film

Perovskite solar cells represent an emerging photovoltaic technology. With the latest record efficiencies exceeding 25% coupled with low fabrication cost and tunable transparency, perovskite solar cells demonstrate promising applications as solar windows. For these applications, the perovskite solar cells need to be semi-transparent to allow incident light to pass through the windows while generating electricity. However, semi-transparency compromises light absorption in the solar cells. In this work, optical enhancement in perovskite thin films using moth-eye anti-reflection (AR) film is investigated. Perovskite thin films with different thicknesses are used and the thickness is controlled by varying the spin speeds during the deposition of the perovskite precursor. The optical effects in the perovskite films without and with moth-eye AR film are studied. From the findings, the reflection loss is reduced by maximum of ∼4%, which contributes to a higher light absorption in the perovskite layer, due to the AR effect of the moth-eye structure. These results imply that the moth-eye film can be a promising and facile alternative for developing a highly efficient and semi-transparent perovskite solar cell with a thin absorber layer.

Thermal Annealing Impact on Optical Properties of Spin-coated P3HT: CdS Thin Film

Polymers are flexible materials that can be easily processed and are formed into a thin film by several methods such as spin-coating, dip-coating, film-casting, and printing. The spin coating method has been extensively utilized in fabricating solution-prepared organic/inorganic electronic devices, this technique is positively efficient in generating thin film apart from being a flexible method to execute. In this study, poly(3-hexylthiophene) (P3HT) material is selected as polymer and cadmium sulphide (CdS) as nanoparticles to produce a hybrid nanocomposite thin film through the process spin-coating method. The P3HT and cadmium ion solution were used to fabricate a thin film onto a quartz glass substrate at a spin speed of 500 rpm for 10 seconds. This spin-coated thin film was heated at different temperatures such as 40°C, 80°C, 120°C, and 160°C for optical properties using a UV-Vis spectrophotometer. The UV-Vis absorption spectra of P3HT: CdS indicated absorption peaks in the UV region, which were ascribed to the band gap of the P3HT: CdS thin film. Our results showed that the optical properties of the P3HT: CdS be contingent on the annealing temperature. The film at room temperature yielded a band gap value of 1.98 eV, at 40°C it resulted in 1.99 eV. The band gap value was increased when annealed at 80°C with 2.02 eV. Annealing temperatures were then raised to 120°C and 160°C, leading to band gap values of 3.11 eV and 2.80 eV respectively.

HR-MAS DREAMTIME NMR for Slow Spinning ex Vivo and in Vivo Samples.

HR-MAS NMR is a powerful tool, capable of monitoring molecular changes in intact heterogeneous samples. However, one of the biggest limitations of 1H NMR is its narrow spectral width which leads to considerable overlap in complex natural samples. DREAMTIME NMR is a highly selective technique that allows users to isolate suites of metabolites from congested spectra. This permits targeted metabolomics by NMR and is ideal for monitoring specific processes. To date, DREAMTIME has only been employed in solution-state NMR, here it is adapted for HR-MAS applications. At high spinning speeds (>5 kHz), DREAMTIME works with minimal modifications. However, spinning over 3-4 kHz leads to cell lysis, and if maintaining sample integrity is necessary, slower spinning (<2.5 kHz) is required. Very slow spinning (≤500 Hz) is advantageous for in vivo analysis to increase organism survival; however, sidebands from water pose a problem. To address this, a version of DREAMTIME, termed DREAMTIME-SLOWMAS, is introduced. Both techniques are compared at 2500, 500, and 50 Hz, using ex vivo worm tissue. Following this, DREAMTIME-SLOWMAS is applied to monitor key metabolites of anoxic stress in living shrimp at 500 Hz. Thus, standard DREAMTIME works well under MAS conditions and is recommended for samples reswollen in D2O or spun >2500 Hz. For slow spinning in vivo or intact tissue samples, DREAMTIME-SLOWMAS provides an excellent way to target process-specific metabolites while maintaining sample integrity. Overall, DREAMTIME should find widespread application wherever targeted molecular information is required from complex samples with a high degree of spectral overlap.

A genetic-continuation algorithm for bifurcation analysis of nonlinear rotordynamic systems

This study presents a combined numerical scheme with genetic algorithm and continuation method for analysing nonlinear vibrations in rotor-bearing systems. A modified genetic algorithm is developed for solving multiple coexisting roots in nonlinear rotordynamic problem. Here, the genetic objective is the completion of periodicity for the boundary values of journal/pad phase states during the consecutive generations. The arc-length continuation takes the role to extend the solutions with respect to operating parameters such as the shaft spin speed and disc mass eccentricity. The resulting bifurcation diagrams, then, can comprehensively show the emergences and disappearances of multiple response states and their stability conditions in detail, which is unlike with the commonly applied numerical integration method. A finite model of heavily loaded Jeffcott rotor supported by six-pad tilting pad journal bearing is utilized to evaluate the developed algorithm. The 150 initial states for the journal and pad are generated, and the 8 optimal results are selected and inbreeded for evolution; it repeats for 15 generations. As results, multiple coexisting responses are identified at the same condition, and various bifurcation events such as periodic doubling, saddle-node are discovered from the solution manifolds.

CFD-DEM investigation of the effects of aperture size for a capsule-based dry powder inhaler

Capsule based dry powder inhalers (DPIs) often require piercing of the capsule before inhalation, and the characteristics of the apertures (punctured holes) affect air flow and the release of powders from the capsule. This work develops a numerical model based on the two-way coupling of computational fluid dynamics and discrete element method (CFD-DEM) to investigate the effect of aperture size on powder dispersion in the Aerolizer® device loaded with only carrier particles (lactose). Powders (carrier particles) in the size range 60–140 μm (d50: 90 μm and span: 0.66) were initialized in a capsule which had a circular aperture at each end. Boundary conditions corresponding to an air flow rate of 45 L/min were specified at each inlet to the mixing chamber (i.e., a total flow rate 90 L/min), and a capsule spin speed of ∼ 4050 rpm. The velocity magnitudes inside the capsule were considerably lower than those in the mixing chamber in the vicinity of the rotating capsule, with the exception of the capsules featuring 2.5 mm and 4 mm apertures. Larger apertures reduced the capsule emptying time and increased the particle evacuation velocity; the fluid drag force on the particles issuing from the capsule peaked for an aperture of 1.3 mm. Inside the capsule, particle–particle (PP) collisions were more frequent than particle–wall (PW) collisions due to high concentration of powder, but PP collisions had smaller (median) impact energy than PW collisions. Larger apertures resulted in fewer collisions in the capsule with higher PW and virtually unchanged PP collision energies. Outside the capsule (i.e., in the inhaler mixing chamber), PW collisions occurred more frequently than PP collisions with median collision energies typically two orders of magnitude higher than inside the capsule. Larger apertures resulted in more collisions with slightly reduced collision energy, but this effect plateaued for aperture sizes larger than 1.3 mm. Powder dispersion, expressed as the fine particle fraction (FPF) of the powder, was predicted using an empirical equation based on carrier PW collisions. Therefore, consistent with the model prediction of the effect of aperture sizes on the chamber collision frequency, FPF increased with aperture size but plateaued beyond 1.3 mm.

Fabrication of hierarchical nanostructures using binary colloidal nanosphere assembly

In this paper, we investigate the self-assembly of hierarchical nanostructures using monodispersed nanospheres with two different diameters. Our approach is to use a two-step method where the assembly of larger 200 nm nanospheres is used to direct the assembly of smaller 50 nm particles. This self-assembly technique is based on Langmuir–Blodgett assembly and has low equipment cost when compared with traditional lithography methods. We examine the effects of substrate surface treatment, solution concentration ratio, and spin speeds on the quality of the hierarchical assembly. The fabricated samples are examined using optical and scanning electron microscopy to investigate assembly yield. Various defect types are identified and mitigated by process control. The ability to create more complex assembly can result in smaller features and can enhance the performance of photonics and nanostructured surfaces.

An Embedded System Approach to Design and Development of an Automatic Spin Coating Machine for Thin Film Applications

A typical spin coating technique entails three steps: dispense, in which the resin fluid is applied to the substrate surface; high-speed spin, in which the fluid is thinned; and drying, in which extra solvents are removed from the resultant film. For the growth of thin films, an embedded system-based spin coating machine has been developed. The PIC microcontroller (PIC16f877A), which might be powered by a driver circuit to drive a spinning motor, controls the spin coating machine effectively. The temperature sensor is used to determine the temperature, while the proximity sensor is used to determine the motor's speed. Using a temperature sensor, the temperature has been kept between 30 and 40 degrees Celsius. The developed system will coat thin films in a micro level thickness by adjusting the spinning speed and controlling the system using PIC microcontroller. To test the reliability and repeatability of the machine, Zinc oxide (ZnO) was prepared with the sol-gel technique and deposited on the glass substrate using embedded system based spin coating machine. ZnO thin films were prepared at different pH and exhibited the fundamental reflections of (100), (002), (101), and (102) with the hexagonal wurtzite crystal structure. The structural studies of ZnO thin films using XRD analysis confirm the presence of ZnO particles in the prepared films. Also, it ensures the prepared ZnO thin film is pure and that no other impurities have been observed in the XRD pattern.

DESIGN AND EXPERIMENT TO DETERMINE OPERATING PARAMETERS FOR SUGARCANE PEELER ACCORDING TO THE PRINCIPLE OF CIRCULAR BRUSH

This paper presents a two-stage experimental process to determine the reasonable operating parameters of the sugarcane peeling machine based on the principle of circular brush. The first stage is to qualitatively determine the quality of sugarcane peeling to determine the speed range of the brush disk. The second stage specifies the value of rotational speed and cane push speed to be able to clean sugarcane with a diameter of the cane stem about 20-40 mm. Based on a reasonable set of parameters, the authors designed and fabricated a prototype of a sugarcane peeling machine with a spinning speed of 750 rpm and a cane pushing speed of 15-20 s/m. The machine has a productivity of 70 canes/hour and wears away an average thickness of about 0.767 mm, satisfying the condition of cleaning sugarcane. The research results are the basis for the mass production of sugarcane peeling machines according to the principle of circular brush with lower cost and higher productivity than other types of sugarcane peeling machines according to the principle of knife.

Tailoring the thermal stability and soft magnetic properties of Fe80-xNixSi7B8P4Cu1 amorphous nanocrystalline alloys based on the magnetic domain structure

Structure, crystallization behavior, dynamic domains, and magnetic properties of as-quenched and annealed Fe80-xNixSi7B8P4Cu1 (x = 0, 1, 2, 3 and 4) alloy ribbons have been investigated. It finds that the partial substitution of Ni for Fe promotes the formation of amorphous structure. We have determined the critical spinning speed for the formation of pre-existing α-Fe cluster structures. In addition, a little increase in Ni content effectively inhibits the excessive growth of the α-Fe grains, which contributes to the reduction of grain size and Hc. Moreover, the role of Ni on the magnetic domain structures and its correlation medel was established. After proper annealing treatment, the Fe79Ni1Si7B8P4Cu1 nanocrystalline alloy exhibited excellent soft-magnetic properties including a high Bs of 1.58 T, a low Hc of 2.48 A/m and a high μe of 16400, which is closely related to the high volume fraction of α-Fe grains and uniform refinement of magnetic domains which is more conducive to the migration and rotation of magnetic domains.

Microwave-assisted fabrication and optimization of nickel cobalt phosphate for high-performance electrochromic supercapacitors

This study uses response surface methodology and central composite design (RSM/CCD) to explore the optimization of nickel cobalt phosphate (NiCoPO4) composites as effective materials for electrodes in electrochromic supercapacitors. The synthesis of NiCoPO4 powder is achieved through microwave-assisted techniques, and spin coating is employed to fabricate the NiCoPO4 composite electrode. Two factors, namely spin speed and time, are simultaneously investigated to assess their impact on the specific capacity of NiCoPO4 composites. Statistical analysis using Design Expert software indicates a quadratic model with a residual standard error of less than 4 %. The NiCoPO4 composites are subjected to various characterization techniques, including FTIR, Raman, XRD, XPS, and FESEM with EDX. Additionally, comprehensive electrochromic energy storage performance analyses are conducted, encompassing EIS, CV, GCD, stability, optical, and kinetic studies. The NiCoPO4 electrode material exhibits distinct color changes, appearing black at 0.5 V and pale green at 0 V, which signify its electrochromic properties. Furthermore, NiCoPO4 electrode material demonstrates exceptional optical performance, with a specific capacitance of 48.95 cm2/C, and supercapacitive performance, with a specific capacity of 262.8C/g, thus highlighting the as-prepared NiCoPO4 potential as a promising electrode material for electrochromic supercapacitors.

Digital process control of multi-step assays on centrifugal platforms using high-low-high rotational-pulse triggered valving.

Due to their capability for comprehensive sample-to-answer automation, the interest in centrifugal microfluidic systems has greatly increased in industry and academia over the last quarter century. The main applications of these "Lab-on-a-Disc" (LoaD) platforms are in decentralised bioanalytical point-of-use / point-of-care testing. Due to the unidirectional and omnipresent nature of the centrifugal force, advanced flow control is key to coordinate multi-step / multi-reagent assay formats on the LoaD. Formerly, flow control was often achieved by capillary burst valves which require gradual increments of the spin speed of the system-innate spindle motor. Recent advanced introduced a flow control scheme called 'rotational pulse actuated valves'. In these valves the sequence of valve actuation is determined by the architecture of the disc while actuation is triggered by freely programmable upward spike (i.e. Low-High-Low (LHL)) in the rotational frequency. This paradigm shift from conventional 'analogue' burst valves to 'digital' pulsing significantly increases the number of sequential while also improving the overall robustness of flow control. In this work, we expand on these LHL valves by introducing High-Low-High (HLH) pulse-actuated (PA) valving which are actuated by 'downward' spike in the disc spin-rate. These HLH valves are particularly useful for high spin-rate operations such as centrifugation of blood. We introduce two different HLH architectures and then combine the most promising with LHL valves to implement the time-dependent liquid handling protocol underlying a common liver function test panel.

Self-cleaning SiO2/TiO2/PMMA nanocomposite films fabricated by spin coating technique: Effect of different spin speed and film layers

This research aims to develop the self-cleaning efficiency of silicon dioxide/titanium dioxide/methyl methacrylate (SiO2/TiO2/PMMA) nanocomposite films proved by optical and structural properties. The SiO2/TiO2/PMMA nanocomposite films were prepared by spin coating technique with the crucial parameters of spin speed and film layers. The ratio of SiO2:TiO2 in SiO2/TiO2 nanocomposite was conducted at 1:1 by sonochemical process and loading at 1 wt.% in PMMA matrix. Spin speed of SiO2/TiO2/PMMA nanocomposite films in coating process was conducted at 1000, 2000, and 3000 rpm with film growth at 2 layers. Meanwhile, the different film layers of the nanocomposite film were selected as other crucial parameter in spin coating technique and studied at 1, 2, and 3 layers with spin speed 2000 rpm. Surface morphologies, cross-section and element contents of SiO2/TiO2/PMMA nanocomposite films with different spinning speed and film layers were monitored by the photographs, field emission scanning electron microscope (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). Moreover, optical property in transmission mode of SiO2/TiO2/PMMA nanocomposite films was characterized by UV-VIS spectrophotometer. Furthermore, the contact angle measurement o f SiO2/TiO2/PMMA nanocomposite films can identify to hydrophilic properties on the film surface. Therefore, the improvement of self-cleaning property on SiO2/TiO2/PMMA nanocomposite film was occurred by the optimized conditions of spinning speed at 2000 rpm and film growth at 2 layers by spin coat technique.

The Influence of Spin Coating Speed on the Optical Properties of P3HT Thin Film

Spin coating technique has been widely used in the fabrication of thin films due to its ease of use, inexpensive processing cost and providing control over the thickness of the film. Various polymers have been used in fabricating spin-coated thin film and poly(3-hexylthiophene) (P3HT) is one of the prevalent polymers utilized due to its semiconducting properties and flexibility in processing. In this study, P3HT is deposited on pre-cleaned quartz glass by the method of spin coating. The spin coating speed is varied from 500, 1000, 1500, 2000, 2500 rpm and the optical properties of the films are characterized by using a UV-Vis spectrophotometer. The UV-Vis absorption spectra of P3HT designated absorption peaks in the range of 520 nm to 550 nm. It is shown that the absorbance of P3HT is decreased with every increment of the spinning speed. Thus revealing the dependency of P3HT thin films’ optical properties on spin coating speed.

Preparation and study of the structural and optical traits of Ag: Zro2 nanostructure thin films prepared via spin coating: Effect of spin speed on thin films properties

Thin films of silver: zirconium oxide (Ag: ZrO2), prepared using the spin coating method (SCM) with 2% silver nitrate (Ag NO3) and 1% zirconium nitrate (Zr (NO3) 4) on glass substrate at room temperature, with different spin speeds (1000, 2000 and 3000) rpm. X-ray diffraction (XRD) and Field Emission scanning electron microscopy were used to investigate the structural properties of the grown silver films. The optical properties of these thin films were distinguished by UV-vis spectroscopy. The films' polycrystalline nanostructure was revealed by X-rays, and the grain size shrank with increasing spin speed (from 1000 to 3000 rpm). The scanning electron microscope showed that the average particle size also decreases from (80.7 - 42.67) nm with an increase in the spin speed from (1000 - 3000). and Uv-vis spectroscopy showed that the transparency of the films increases, while the absorbance, coefficient attenuation, and absorption coefficient of the films decrease when the spin speed increases

Controlling the structure of spin-coated multilayer ethylcellulose/hydroxypropylcellulose films for drug release

Porous phase-separated ethylcellulose/hydroxypropylcellulose (EC/HPC) films are used to control drug transport out of pharmaceutical pellets. Water-soluble HPC leaches out and forms a porous structure that controls the drug transport. Industrially, the pellets are coated using a fluidized bed spraying device, and a layered film exhibiting varying porosity and structure after leaching is obtained. A detailed understanding of the formation of the multilayered, phase-separated structure during production is lacking. Here, we have investigated multilayered EC/HPC films produced by sequential spin-coating, which was used to mimic the industrial process. The effects of EC/HPC ratio and spin speed on the multilayer film formation and structure were investigated using advanced microscopy techniques and image analysis. Cahn-Hilliard simulations were performed to analyze the mixing behavior. A gradient with larger structures close to the substrate surface and smaller structures close to the air surface was formed due to coarsening of the layers already coated during successive deposition cycles. The porosity of the multilayer film was found to vary with both EC/HPC ratio and spin speed. Simulation of the mixing behavior and in situ characterization of the structure evolution showed that the origin of the discontinuities and multilayer structure can be explained by the non-mixing of the layers.