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Abstract Monte Carlo simulation is employed using the bond‐fluctuation model (BFM) to explore the role of free‐monomer model on surface‐initiated controlled polymerization from flat substrates. Three free‐monomer models differ in two aspects: 1) their extent of excluded volume interactions between free‐monomer/polymer segments and 2) monomer availability (finite or infinite) during the simulation. In the explicit monomer (EM) model, free‐monomers behave as a single BFM‑type units. In the phantom monomer (PM) model, free‐monomers act analogously to those in the EM model but lack excluded volume interactions with the growing polymers. In the implicit monomer (IM) model, no explicit monomers are included in the simulation box; the polymers can grow as long as space is available near active chain‐ends. It is found that the breadth of the molecular weight distribution of the grown polymers decreases from EM, to PM, to IM models. With the EM model, free‐monomers are excluded from the near‐surface region, while with the PM model they are not. Due to its excluded volume interactions, the EM model tends to compress the brush against the substrate. Finally, the relaxation of the shape of a polydisperse brush after the polymerization reaction ends has been reported.
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Side‐Chain Control of Topochemical Polymer Single Crystals with Tunable Elastic Modulus
Abstract Topochemical polymerizations hold the promise of producing high molecular weight and stereoregular single crystalline polymers by first aligning monomers before polymerization. However, monomer modifications often alter the crystal packing and result in non‐reactive polymorphs. Here, we report a systematic study on the side chain functionalization of the bis(indandione) derivative system that can be polymerized under visible light. Precisely engineered side chains help organize the monomer crystals in a one‐dimensional fashion to maintain the topochemical reactivity. By optimizing the side chain length and end group of monomers, the elastic modulus of the resulting polymer single crystals can also be greatly enhanced. Lastly, using ultrasonication, insoluble polymer single crystals can be processed into free‐standing and robust polymer thin films. This work provides new insights on the molecular design of topochemical reactions and paves the way for future applications of this fascinating family of materials.
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- PAR ID:
- 10382538
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 61
- Issue:
- 49
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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