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Vapor phase infiltration (VPI) enables the fabrication of novel organic–inorganic hybrid materials with distinctive properties by infiltrating polymers with inorganic species through a top-down approach. However, understanding the process kinetics is challenging due to the complex interplay of sorption, diffusion and reaction processes. This study examines how polymer network flexibility affects the kinetics of diethylzinc (DEZ) infiltration into a highly crosslinked polyacrylate copolymer system composed of two monomers: trimethylolpropane triacrylate (TMPTA) and ethoxylated trimethylolpropane triacrylate (ETPTA). The findings show that increasing the ratio of ETPTA, which enhances network flexibility, facilitates precursor diffusion, resulting in deeper infiltration and faster saturation. A reaction–diffusion transport model is employed to qualitatively interpret the experimental results and gain insights into the underlying process mechanisms, thus contributing to a better understanding of VPI kinetics. 

Photopatterning of polymers enables the microfabrication of numerous microelectronic, micromechanical, and microchemical systems. The incorporation of inorganics into a patterned polymer material can generate many new interesting properties such as enhanced stability, optical performance, or electrical properties. Vapor phase infiltration (VPI) allows for the creation of hybrid organic–inorganic materials by infiltrating polymers with gaseous metalorganic precursors. This study seeks to explore the potential of integrating VPI with existing photopatterning techniques to achieve top-down hybridization and property modification of polymer structures of different complexity. For this, VPI of diethylzinc (DEZ) is studied for four highly crosslinked acrylate networks that can be patterned by photolithography and two-photon polymerization (2PP): pentaerythritol triacrylate (PETA), pentaerythritol tetraacrylate (PETeA), trimethylolpropane triacrylate (TMPTA) and ethoxylated trimethylolpropane triacrylate (ETPTA). The findings show that for highly crosslinked polymer networks, VPI can be limited by slow precursor diffusion. However, by introducing flexible segments (e.g., ethoxylated chains), the polymer's free volume can be increased, and infiltration is accelerated, leading to faster infiltration times and higher and more uniform inorganic loading. Finally, selective infiltration of ZnO into photolithographically patterned copolymer networks of TMPTA and ETPTA on non-infiltrating poly(methyl methacrylate) (PMMA) is demonstrated illustrating the potential of VPI for advanced maskless patterning strategies. 

Elastomers are an important class of polymers for many applications. Often, additives are added to the polymer matrix of elastomers to promote vulcanization or enhance physical or chemical properties. In this study, vapor phase infiltration (VPI) is investigated for transforming unvulcanized cis -polyisoprene (from natural rubber) into an organic/inorganic hybrid material. Specifically, we examine single-cycle infiltration with diethylzinc (DEZ) and water to form infiltrated zinc oxide species. Interestingly, low-temperature pre-heating of the cis -polyisoprene acutely affects the processes of infiltration, including diffusivity, maximum solubility, and chemical reactivity. We attribute these effects to a combination of film relaxation and oxidation. Independent of thermal pre-treatments, all infiltration processes exhibited consistent zinc oxide loading irrespective of purge time between the DEZ and water doses, indicating the presence of a strongly bound intermediate state between the DEZ precursor and the cis -polyisoprene polymer. Increasing infiltration process temperature accelerates diffusion and lowers the maximum solubility, in accordance with Fick's law and gas phase sorption equilibrium. Resulting organic–inorganic hybrid films show enhanced resistance to dissolution in toluene, a good solvent for the pure polymer.