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oai:www.ideals.illinois.edu:2142/97648 2023-07-11 col_2142_5131 col_2142_13836 com_2142_5130 com_2142_13835 com_2142_234

Cheng, Jianjun Cheng, Jianjun Braun, Paul Sottos, Nancy Kilian, Kristopher Moore, Jeffrey Ying, Hanze 2017-08-10T20:32:21Z 2017-08-10T20:32:21Z 2019-08-11T09:15:21Z 2017-01-04 2017-05 Dynamic covalent bonds (DCBs) featuring reversible bonding/debonding properties have found various applications in dynamic materials designs such as self-healing, malleable, shape-memory or environmentally-adaptive materials. However, most DCBs developed so far require either catalyst or harsh environments to facilitate bond reversion and involve special building blocks for synthesis. Here we seek to develop a novel platform for dynamic materials design using a new type of DCB – hindered urea bond (HUB). Differing from normal urea bond, HUB bears bulky substituents on one of the nitrogen atom, which distorts the atomic co-planarity, weakens the bonding stability, and allows reversible dissociation of HUB to isocyanate and hindered amine. The dynamic properties of HUB enables the design of self-healing polymeric elastomers/malleable thermosets through bond exchange and hydrolyzable polymers through quenching of dissociative intermediate – isocyanate. HUB shows many advantages in dynamic materials designs compared with other DCB systems in terms of simplicity, dynamicity, tunability and cost. Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2019-05-01 The student, Hanze Ying, accepted the attached license on 2016-12-22 at 04:40. The student, Hanze Ying, submitted this Dissertation for approval on 2016-12-22 at 05:12. This Dissertation was approved for publication on 2017-01-04 at 15:34. DSpace SAF Submission Ingestion Package generated from Vireo submission #10523 on 2017-08-10 at 15:04:01 Made available in DSpace on 2017-08-10T20:32:21Z (GMT). No. of bitstreams: 4 YING-DISSERTATION-2017.pdf: 6429891 bytes, checksum: fa60033720adae8e76d10fafc422863c (MD5) final thesis -- Hanze Ying.docx: 32050622 bytes, checksum: 9a762243ab3341d20c3610ff6f9b9cd5 (MD5) LICENSE.txt: 4207 bytes, checksum: 1b127122bfffd729b5b26ffae92bbc67 (MD5) PROQUEST_LICENSE.txt: 4553 bytes, checksum: c1603755bc1a6e62caa7db91897d50e1 (MD5) Previous issue date: 2017-01-04 Embargo set by: Colleen Fallaw for item 102701 Lift date: 2019-08-10T21:27:21Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system U of I Only Restriction Lifted for Item 102701 on 2019-08-11T09:15:21Z. application/pdf http://hdl.handle.net/2142/97648 en Copyright 2016 Hanze Ying Dynamic covalent chemistry Hindered urea bond (HUB) Dynamic polymers Self-healing Hydrolyzable Malleable thermoset Hindered urea bond for the design of dynamic materials text text Materials Science & Engineerng Materials Science & Engr University of Illinois at Urbana-Champaign Dissertation Ph.D.