## 2 Materials and Methods  
Calcium hydride (CaH\({}_{2}\)), sec-butyllithium in cyclohexane (1.4 M), sodium metal, benzophenone, platinum (0), deuterated chloroform (CDCl\({}_{3}\)), 1,1\({}^{\prime}\)-(Methylenedi-4,1-phenylene) bismaleimide (BMI), nitrobenzene, anhydrous potassium carbonate, and methyl triphenylphosphonium bromide were purchased from Millipore Sigma chemical company. Furfural, Styrene (S), divinylbenzene (DVB), hexamethylcyclotrisiloxane (D3), chlorodimethylsilane, and tetrahydrofuran (THF) were also purchased from Millipore Sigma and were purified before use. The procedures of purification are described below in detail. Methanol, 2-Propanol, and (2,2,6,6-Tetramethylpiperidin-1-yl) oxyl (TEMPO) were purchased from the Fisher Chemical Company. 2-Vinylfuran was synthesized in our lab, and a 1\({}^{\mathrm{H}}\)NMR spectrum is provided to demonstrate purity (Figure S1). [PERSON]'s catalyst (H\({}_{2}\)PtCl\({}_{6}\)) was purchased from Millipore Sigma (St. Louis, MO, USA). The hydrosilylation reactions were conducted under an inert nitrogen atmosphere. Tetrahydrofuran (THF) was purified by refluxing over sodium metal in the presence of benzophenone. A styrene and divinylbenzene mixture (90:10 S/DVB) was stirred overnight over finely powdered calcium hydride. On the vacuum line, the mixture was frozen-degassed-thawed three times before being distilled into pre-calibrated high-vacuum storage tubes. Styrene, hexamethylcyclotrisiloxane (D3), 2-vinylfuran, and the terminating agent chlorodimethylsilane were purified similarly. Synthesis of Furan end-functionalized Hairy nanoparticles (HNP-Fs):  
The HNPs functionalized with furan were synthesized by the high-vacuum living anionic polymerization technique. The high-vacuum storage tubes containing the mixture of a monomer and crosslinker (S and DVB), hexamethylcyclotrisiloxane (D3), chlorodimethylsilane, 2-vinylfuran, and tetrahydrofuran (THF) were attached in advance to the reactor. The reactor was placed under high vacuum and flushed several times with dry nitrogen. At first, 25 mL of dry distilled THF was transferred to the reactor from a high-vacuum storage tube. After that, the mixture of styrene (1.50 g) and divinylbenzene (0.22 g) was transferred to the reactor. The temperature of the monomer solution was reduced to \(-\)78 \({}^{\circ}\)C. Under vigorous stirring, 1 mL of sec-BuLi was rapidly added to the reactor by septum. The color of the reaction mixture immediately turned red, which is char  
Figure 1: Schematic illustration of crosslinking and decrosslinking of furan functionalized HNPs with bismaleimide. styryllithium anion, indicating the occurrence of anionic polymerization. The first-step polymerization was carried out at \(-78\)\({}^{\circ}\)C for 1.5 h. The second-step polymerization was initiated by the living styryllithium anion by adding 1.80 g of hexamethylcyclotrisiloxane (D3) dissolved in THF to the reaction mixture and gradually warming the reactor temperature to room temperature. The red color initially became orange and lightened over time until finally it disappeared completely. The second polymerization was then carried out at room temperature for 15 h. Finally, purified chlorodimethylsilane was added to the reactor from a high-vacuum storage tube to the reactor to terminate the polymerization. After 30 min, 2 mL of the reaction mixture was pulled by syringe and precipitated in methanol for \({}^{1}\)H NMR and FTIR characterization before adding 0.3 gm 2-vinylfuran monomer to the reactor. Under continuous dry nitrogen flow to the reactor, 3-5 drops of [PERSON]'s catalyst (H\({}_{2}\)PtCl\({}_{6}\)) and 5 mol% of TEMPO dissolved in dry THF were added, and the reaction was conducted for another 24 h at room temperature to complete the hydrosilylation reaction. Then, the resulting polymer was precipitated into a large excess of methanol. It was dried in a vacuum oven at room temperature to produce 3.5 g furan functionalized HNPs.