Blends of polymers with microporous particles are essential to many modern technologies, including membranes, catalysts, nanocomposites, and porous liquids. However, the design space and performance of these technologies are substantially limited because it is difficult to quantify and control how polymers thread into the particles' sub-2 nm micropores. Here, we address these issues with two new strategies. First, we show that traditional solution-state NMR can be used to directly monitor polymer chains and quanti…