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Abstract Network formation in elastomers with grafted side chains is investigated to understand the entanglement‐free nature of the bottlebrush architecture. Competition between elastically effective cross‐linkers and dangling side chains creates a unique environment where reaction kinetics and steric effects dictate network percolation. The evolving viscoelasticity of linear and bottlebrush networks with an equivalent number of cross‐linkers to backbones is measured during a catalytic curing reaction using time‐resolved rheology. The impact of reaction kinetics on network formation is addressed through the sol−gel transition by tuning catalyst concentration. Solidification falls into a rate‐limited regime where the modulus growth rate increases with increasing catalyst. The network formation process remains independent of the cure rate in the bottlebrush and linear systems. Side chains significantly decrease the fractal dimension of the critical gel cluster despite a comparable number of cross‐links. Time‐cure superposition is applied to quantify dynamics in the pre‐ and post‐gel states. The divergence of the shift factors around the gel point is independent of cure kinetics. The collapse of shift factors in the post‐gel region further suggests the universality of the network formation process. The approach to understanding internal structure development during processing will be critical as bottlebrush elastomers are utilized among a wide range of applications. 

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. 

In this review, we discuss the structural properties of the three most common types of silicone surfaces and their static and dynamic wetting properties. We review experimental and theoretical approaches for soft wetting.