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Title: Living additive manufacturing: Transformation of parent gels into diversely functionalized daughter gels made possible by visible light photoredox catalysis

Light-initiated additive manufacturing techniques typically rely on layer-by-layer addition or continuous extraction of polymers formed via nonliving, free radical polymerization methods that render the final materials “dead” toward further monomer insertion; the polymer chains within the materials cannot be reactivated to induce chain extension. An alternative “living additive manufacturing” strategy would involve the use of photocontrolled living radical polymerization to spatiotemporally insert monomers into dormant “parent” materials to generate more complex and diversely functionalized “daughter” materials. Here, we demonstrate a proof-of-concept study of living additive manufacturing using end-linked polymer gels embedded with trithiocarbonate iniferters that can be activated by photoinduced single-electron transfer from an organic photoredox catalyst in solution. This system enables the synthesis of a wide range of chemically and mechanically differentiated daughter gels from a single type of parent gel via light-controlled modification of the parent’s average composition, strand length, and/or cross-linking density. Furthermore, daughter gels that are softer than their parent, stiffer than their parent, larger but with the same modulus as their parent, thermally responsive, polarity responsive, healable, and weldable are all realized.
 [1] ;  [2] ;  [3] ; ORCiD logo [4] ;  [5] ;  [3] ; ORCiD logo [5] ;  [3] ; ORCiD logo [2]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Fudan Univ., Shanghai (China)
  2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  3. Univ. of Pittsburgh, Pittsburgh, PA (United States)
  4. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Yale Univ., New Haven, CT (United States)
  5. Case Western Reserve Univ., Cleveland, OH (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
ACS Central Science
Additional Journal Information:
Journal Volume: 3; Journal Issue: 2; Journal ID: ISSN 2374-7943
American Chemical Society (ACS)
Research Org:
Univ. of Pittsburgh, Pittsburgh, PA (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; transfer radical polymerization; cross-linked polymers; cationic-polymerization; model networks; hydrogels; trithiocarbonate; transition; driven; growth; elasticity; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1358429