Molecular dynamics simulation method applied to nanocavities replication via injection moulding

Pina-Estany, J.; García-Granada, A. A.

doi:10.1016/j.icheatmasstransfer.2017.06.018

Cited by 22 publications

(18 citation statements)

References 16 publications

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“…The commonly used methods to simulate the micro-injection molding process are FEM based on continuum theory 8,10,11 and molecular dynamics (MD) simulation. [17][18][19] Due to the scale effect, the adhesion force of the microstructure in the demolding process mainly depends on the non-bond interaction at the polymer-mold interface. Therefore, MD simulation is applicable to the analysis of interfacial mechanism at the molecular and atomic levels, providing theoretical guidance for nondestructive demolding.…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics simulation on the adhesion mechanism at polymer‐mold interface of microinjection molding

Yang

Zhai

Liu

et al. 2020

J of Applied Polymer Sci

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In the demolding process of microinjection molding, the defects of microstructures are often caused by the strong adhesion between polymer and mold. In order to study the adhesion mechanism, the molecular dynamics (MD) method was proposed to simulate the adsorption of cycloolefin copolymer (COC) molecules on mold surfaces. The evolution snapshots of COC molecular chains of three interfacial models were obtained to directly demonstrate the adhesive strength of interfaces. Meanwhile, the work of adhesion, the relative concentration, the potential energy, and the radial distribution function (RDF) were calculated to explain the interaction mechanism of polymer-mold interfaces. The simulation results showed that the COC-Ni interface had the largest work of adhesion and the lowest potential energy, compared with other two interfaces. The van der Waals (VDW) energy, which mainly derived from the interaction between H atoms in COC and the mold material was the only nonbond interaction energy at the COC-Ni and COC-Si interfaces, while the electrostatic energy existed in COC-Al 2 O 3 interface. In order to reduce the adhesion between polymer and mold, fluorine (F) element could be doped into the Ni mold.

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Section: Introductionmentioning

confidence: 99%

Molecular dynamics simulation on the adhesion mechanism at polymer‐mold interface of microinjection molding

Yang

Zhai

Liu

et al. 2020

J of Applied Polymer Sci

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“…Pina-Estany et al studied the heat transfer coefficient (HTC), between the polyethylene and the nickel mold insert in different nanocavity areas. The results showed that increasing the surface-to-volume could improve the thermal transport properties [ 12 ]. The study of ITR in injection molding by MD method is rarely reported in the literature.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Interface Thermal Resistance between Polymer and Mold Insert in Micro-Injection Molding by Non-Equilibrium Molecular Dynamics

et al. 2020

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Micro-injection molding has attracted a wide range of research interests to fabricate polymer products with nanostructures for its advantages of cheap and fast production. The heat transfer between the polymer and the mold insert is important to the performance of products. In this study, the interface thermal resistance (ITR) between the polypropylene (PP) layer and the nickel (Ni) mold insert layer in micro-injection molding was studied by using the method of non-equilibrium molecular dynamics (NEMD) simulation. The relationships among the ITR, the temperature, the packing pressure, the interface morphology, and the interface interaction were investigated. The simulation results showed that the ITR decreased obviously with the increase of the temperature, the packing pressure and the interface interaction. Both rectangle and triangle interface morphologies could enhance the heat transfer compared with the smooth interface. Moreover, the ITR of triangle interface was higher than that of rectangle interface. Based on the analysis of phonon density of states (DOS) for PP-Ni system, it was found that the mismatch between the phonon DOS of the PP atoms and Ni atoms was the main cause of the interface resistance. The frequency distribution of phonon DOS also affected the interface resistance.

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“…Thus, it is very important to further study the interfacial interactions in the fabrication of polymer microstructures from the molecular or atomic level. Molecular dynamics (MD) simulation methods for the analysis of interfacial interactions have been widely applied in nanoimprint lithography (NIL) [22,23], interfacial mechanisms [24,25], polymer injection molding [26,27], pulling simulations in diverse molecular systems [28,29] and other fields, which can accurately analyze the interaction mechanism of polymer-mold insert during the polymer molding process. Hsu et al [30,31] used the MD method to study the influences of temperature, the aspect ratio of the stamp, and the anti-sticking layer on the polymer molding quality in the NIL process.…”

Section: Introductionmentioning

confidence: 99%

Influence of Diamond-Like Carbon Coating on the Channel Deformation of Injection-Molded Microfluidic Chips during the Demolding Process

et al. 2020

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Injection molding is one of the main techniques for manufacturing microfluidic chips. As an important stage, the demolding process in injection molding will directly affect the quality of the functional unit of microfluidic chips (polymer microchannels), thus limiting the realization of its functions. In this study, molecular dynamics (MD) simulations on the demolding process were carried out to investigate the influence of diamond-like carbon (DLC) coating on the channel deformation. The channel qualities of polystyrene (PS), polymethyl methacrylate (PMMA), cyclic olefin copolymer (COC) and polycarbonate (PC) were analyzed after demolding with nickel (Ni) and DLC-coated mold inserts, respectively. In particular, the non-bonded interfacial interaction energy, elastic recovery and gyration radius of polymer molecular chains were further studied. The results showed that the non-bonded interfacial interaction energies could be significantly reduced by DLC-coating treatment on the mold insert. Moreover, common channel defects such as molecular chain separation, surface burrs and necking did not occur. The treatment of DLC coating could also significantly reduce the change in the gyration radius of polymer molecular chains, so the morphology of the polymer channel could be maintained well. However, the change in the elastic recovery of the polymer channel was increased, and the opening width became larger. In a word, DLC-coating treatment on the mold insert has great application potential for improving the demolding quality of injection-molded microfluidic chips.

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Molecular dynamics simulation method applied to nanocavities replication via injection moulding

Cited by 22 publications

References 16 publications

Molecular dynamics simulation on the adhesion mechanism at polymer‐mold interface of microinjection molding

Molecular dynamics simulation on the adhesion mechanism at polymer‐mold interface of microinjection molding

Investigation of Interface Thermal Resistance between Polymer and Mold Insert in Micro-Injection Molding by Non-Equilibrium Molecular Dynamics

Influence of Diamond-Like Carbon Coating on the Channel Deformation of Injection-Molded Microfluidic Chips during the Demolding Process

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