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ABSTRACT Dynamically crosslinked polymer networks, characterized by non‐permanent bonds, offer unique viscoelastic properties that can be used for various applications such as self‐healing coatings and reusable adhesives. This study investigates the spreading behavior of a silicone polymer network with dynamic imine bonds, focusing on the relationship between material properties and spreading dynamics. We prepare polydimethylsiloxane (PDMS) networks with varied rheological properties by adjusting the ratio of amine and aldehyde groups and curing conditions. The spreading of PDMS spherical drops is investigated on surfaces with different surface energies, with the process quantified by measuring the contact length and height over time. Our findings reveal that higher modulus spheres spread more slowly, and that the spreading length increases more on high energy surfaces. This research could provide insights for developing coatings and adhesives with tunable properties by studying the interaction between transiently‐crosslinked polymers and substrates during spreading. 

Phase separation dynamics of oil from swollen elastomers in a wetting ridge depends on oil viscosity and swelling ratio, which changes for early and late stages of wetting. 

Variable-pressure electron-beam lithography (VP-EBL) employs an ambient gas at subatmospheric pressures to reduce charging during electron-beam lithography. VP-EBL has been previously shown to eliminate pattern distortion and provide improved resolution when patterning poly(methyl methacrylate) (PMMA) on insulating substrates. However, it remains unknown how water vapor affects the contrast and clearing dose nor has the effect of water vapor on the negative-tone behavior of PMMA been studied. In addition, water vapor has recently been shown to alter the radiation chemistry of the VP-EBL process for Teflon AF. Such changes in radiation chemistry have not been explored for PMMA. In this work, VP-EBL was conducted on conductive substrates to study the effect of water vapor on PMMA patterning separately from the effects of charge dissipation. In addition, both positive and negative-tone processes were studied to determine the effect of water vapor on both chain scission and cross-linking. The contrast of PMMA was found to improve significantly with increasing water vapor pressure for both positive and negative-tone patterning. The clearing dose for positive-tone patterning increases moderately with vapor pressure as would be expected for electron scattering in a gas. However, the onset set dose for negative-tone patterning increased dramatically with pressure revealing a more significant change in the exposure mechanism. X-ray photoelectron spectra and infrared transmission spectra indicate that water vapor only slightly alters the composition of exposed PMMA. Also, electron scattering in water vapor yielded a much larger clear region around negative-tone patterns. This effect could be useful for increasing the range of the developed region around cross-linked PMMA beyond the backscattered electron range. Thus, VP-EBL for PMMA introduces a new means of tuning clearing/onset dose and contrast, while allowing additional control over the size of the cleared region around negative-tone patterns.