Thermally Induced Nanoimprinting of Biodegradable Polycarbonates Using Dynamic Covalent Cross-Links

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• 作者：Wiriya Thongsomboon ; Mark Sherwood ; Noel Arellano ; Alshakim Nelson
• 刊名：ACS Macro Letters
• 出版年：2013
• 出版时间：January 15, 2013
• 年：2013
• 卷：2
• 期：1
• 页码：19-22
• 全文大小：254K
• 年卷期：v.2,no.1(January 15, 2013)
• ISSN：2161-1653

文摘

The introduction of reversible covalent bonds into polymeric systems afford robust, yet dynamic, materials that can respond to external stimuli. A series of aliphatic polycarbonate polymers were synthesized via ring-opening polymerization of furanyl and maleimido-bearing cyclic carbonate monomers. These side chains undergo thermally induced Diels鈥揂lder reactions to afford cross-linked films. Because both the diene and dienophile were incorporated into the same polymer backbone, a protected maleimido group, in the form of the furan adduct, was used. Both the forward and reverse Diels鈥揂lder reaction are triggered thermally, which allows the deprotection of the maleimido group and the subsequent reaction with the furanyl side chains to form cross-links. Random copolymers and poly(ethylene glycol) containing block copolymers were formed using diazabicyclo[5.4.0]undec-7-ene as the catalyst and a thiourea cocatalyst. The polymers form uniform films that can be cross-linked in the bulk state. To further illustrate the dynamic nature of the covalent bonds within the cross-linked films, a patterned silicon mold was used to transfer a series of nanoscale patterns using a thermal nanoimprint process.