Mathieu L Lepage, Stefania F Musolino, Jeremy E Wulff
{"title":"Design, Exploitation, and Rational Improvements of Diazirine-Based Universal Polymer Crosslinkers.","authors":"Mathieu L Lepage, Stefania F Musolino, Jeremy E Wulff","doi":"10.1021/acs.accounts.4c00509","DOIUrl":null,"url":null,"abstract":"<p><p>ConspectusAddition of new covalent bonds between the chains of thermoplastic polymers (i.e., crosslinking) provides improved mechanical strength and enhanced high-temperature performance while also providing an effective strategy for photopatterning. Traditionally, however, crosslinking of each polymer substrate has required the use of a specific crosslinking technology (hydrosilylation for PDMS, vulcanization for rubber, etc.). The lack of a general solution to the challenge of polymer crosslinking means that there are many thermoplastics (e.g., polypropylene or polyhydroxyalkanoates) that have desirable properties, but which cannot be upgraded by traditional crosslinking technologies.Our lab developed the first universal crosslinkers for aliphatic polymers by leveraging trifluoromethyl aryl diazirine motifs, functional groups that have been widely used in chemical biology for >30 years, but which have seldom been exploited in materials science. These novel reagents work (via C-H insertion) on essentially any commodity polymer that contains aliphatic C-H bonds, including industrial plastics like polypropylene (the crosslinking of which has been an outstanding challenge in the field for >50 years), as well as commercially important elastomers (e.g., polydimethylsiloxane), biodegradable polymers (e.g., polycaprolactone), and green polymer materials derived from biomass (e.g., polyhydroxyalkanoates).Subsequent structure-function work from our group led to crosslinkers that were >10-fold more effective in undergoing C-H insertion with aliphatic substrates. We then developed an improved synthesis of our electronically optimized diazirines and incorporated them into a family of cleavable crosslinker reagents, which permit the on-demand generation of reprocessable thermosets. At the same time, other groups replaced the perfluoropropyl linker in our first-generation crosslinker with a series of dynamic linkages; these permit the ready generation of vitrimeric materials and can be used in the reactive compatibilization of immiscible plastic waste.Since the publication of our initial <i>Science</i> paper in 2019, this burgeoning field of diazirine-based polymer crosslinkers has experienced an explosion of interest. Publications from our lab and others have described the use of these reagents in covalent adhesion, photopatterning of low dielectric materials for microelectronics, and direct optical printing of quantum dots. Our crosslinkers have also been shown to heighten the robustness of ice-phobic coatings and improve the performance of woven ballistic fabric, while─perhaps most unexpectedly─substantially improving the stability of high-performance perovskite solar cells. Electronically optimized diazirines can also be used to covalently link proteins to polymer surfaces, suggesting a broad range of applications in the biocompatibilization of medical devices. This Account will summarize the development of trifluoromethyl aryl diazirine reagents for materials science over the past 5 years. A brief comparison will also be made, in the Summary and Outlook section at the end of the Account, to competing (and often complementary) reagents based upon azide and diazoalkyl motifs. Finally, we have compiled a Frequently Asked Questions list that covers many practical aspects of crosslinker design and application; this is appended as Supporting Information.</p>","PeriodicalId":1,"journal":{"name":"Accounts of Chemical Research","volume":null,"pages":null},"PeriodicalIF":16.4000,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Accounts of Chemical Research","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acs.accounts.4c00509","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
ConspectusAddition of new covalent bonds between the chains of thermoplastic polymers (i.e., crosslinking) provides improved mechanical strength and enhanced high-temperature performance while also providing an effective strategy for photopatterning. Traditionally, however, crosslinking of each polymer substrate has required the use of a specific crosslinking technology (hydrosilylation for PDMS, vulcanization for rubber, etc.). The lack of a general solution to the challenge of polymer crosslinking means that there are many thermoplastics (e.g., polypropylene or polyhydroxyalkanoates) that have desirable properties, but which cannot be upgraded by traditional crosslinking technologies.Our lab developed the first universal crosslinkers for aliphatic polymers by leveraging trifluoromethyl aryl diazirine motifs, functional groups that have been widely used in chemical biology for >30 years, but which have seldom been exploited in materials science. These novel reagents work (via C-H insertion) on essentially any commodity polymer that contains aliphatic C-H bonds, including industrial plastics like polypropylene (the crosslinking of which has been an outstanding challenge in the field for >50 years), as well as commercially important elastomers (e.g., polydimethylsiloxane), biodegradable polymers (e.g., polycaprolactone), and green polymer materials derived from biomass (e.g., polyhydroxyalkanoates).Subsequent structure-function work from our group led to crosslinkers that were >10-fold more effective in undergoing C-H insertion with aliphatic substrates. We then developed an improved synthesis of our electronically optimized diazirines and incorporated them into a family of cleavable crosslinker reagents, which permit the on-demand generation of reprocessable thermosets. At the same time, other groups replaced the perfluoropropyl linker in our first-generation crosslinker with a series of dynamic linkages; these permit the ready generation of vitrimeric materials and can be used in the reactive compatibilization of immiscible plastic waste.Since the publication of our initial Science paper in 2019, this burgeoning field of diazirine-based polymer crosslinkers has experienced an explosion of interest. Publications from our lab and others have described the use of these reagents in covalent adhesion, photopatterning of low dielectric materials for microelectronics, and direct optical printing of quantum dots. Our crosslinkers have also been shown to heighten the robustness of ice-phobic coatings and improve the performance of woven ballistic fabric, while─perhaps most unexpectedly─substantially improving the stability of high-performance perovskite solar cells. Electronically optimized diazirines can also be used to covalently link proteins to polymer surfaces, suggesting a broad range of applications in the biocompatibilization of medical devices. This Account will summarize the development of trifluoromethyl aryl diazirine reagents for materials science over the past 5 years. A brief comparison will also be made, in the Summary and Outlook section at the end of the Account, to competing (and often complementary) reagents based upon azide and diazoalkyl motifs. Finally, we have compiled a Frequently Asked Questions list that covers many practical aspects of crosslinker design and application; this is appended as Supporting Information.
期刊介绍:
Accounts of Chemical Research presents short, concise and critical articles offering easy-to-read overviews of basic research and applications in all areas of chemistry and biochemistry. These short reviews focus on research from the author’s own laboratory and are designed to teach the reader about a research project. In addition, Accounts of Chemical Research publishes commentaries that give an informed opinion on a current research problem. Special Issues online are devoted to a single topic of unusual activity and significance.
Accounts of Chemical Research replaces the traditional article abstract with an article "Conspectus." These entries synopsize the research affording the reader a closer look at the content and significance of an article. Through this provision of a more detailed description of the article contents, the Conspectus enhances the article's discoverability by search engines and the exposure for the research.