Adhesion and mechanical properties of poly(dimethylsiloxane) bottlebrush elastomers

Abstract

Poly(dimethyl siloxane) (PDMS) bottlebrush elastomers (BBEs) are attractive soft materials with well-controlled bulk mechanical properties. However, their surface and interfacial properties have not been studied in depth. We report a...

Understanding the role of crosslink density and linear viscoelasticity on the shear failure of pressure-sensitive-adhesives

“…In this regard, we deem it worthwhile to investigate how novel molecular architectures like bottlebrush polymer networks behave in shear. 32,33…”

Bottlebrush Networks: A Primer for Advanced Architectures

“…ends, RP BBNs have been synthesized via end-linking of polymers, [107,108] covalent crosslinking via telechelic macromonomers, [1,4,6,7,17,18,35,85,[109][110][111][112][113][114][115][116][117][118] or through the formation of physical entanglements from linear-brush-linear copolymers [5,116,[119][120][121] (plastomers). Importantly, the very first "super-soft" BBNs were synthesized via a combination of grafting-through and grafting from ATRP in 2006, [122] with the architecture remaining unexplored until 2014.…”

“…Importantly, the very first "super-soft" BBNs were synthesized via a combination of grafting-through and grafting from ATRP in 2006, [122] with the architecture remaining unexplored until 2014. [123] Additionally, a large volume of research on BBEs is currently based upon RP chemistry, where materials with poly (caprolactone), [114] poly (isobutylene), [18,35,117] poly (ethylene glycol), [18,110,113,124] poly (n-butyl acrylate), [1,17,34,111,113,117,125] poly (dimethyl siloxane) [1,[4][5][6][7]17,18,85,110,111,115,118,119,124] and polystyrene [35] side chains have been synthesized.…”

“…[1][2][3] This particular property has been capitalized upon in the form of bottlebrush elastomers (BBEs), where the lack of entanglements allows for supersoft materials (Young's modulus ranging from 10 2 -10 6 Pa) in the absence of diluents (free chain or solvent). [2,[4][5][6][7][8][9][10][11] It should be noted that if the length of side chains becomes larger than some critical amount they will form entanglements with adjacent side chains, ostensibly reducing the impact of this special property of BBNs. [12,13] While BBNs (specifically BBEs) thus far have been primarily synthesized by radical polymerization (RP), additional approaches have surfaced as the BBN architecture has become more broadly studied (Figure 2a-b), albeit with only a limited pool of side chain chemistries (Figure 2c).…”

Network Constitutional Isomers

“…Fortunately, the easy-to-manipulate architecture of bottlebrush polymers and bottlebrush networks (BBNs) present an elegant solution to this problem. − BBNs are a class of polymer networks where the high grafting density and length of side chains stretch the polymeric backbone and its side-chains due to steric repulsion, leading to a marked lack of physical entanglements. − Polymerization of BBNs via a living polymerization method would provide direct control over R K in a material in which the effects of entanglements can be disregarded. The highly popular ring-opening metathesis polymerization (ROMP) is uniquely positioned to study the role of R K in BBNs due to its high conversion, living nature, lack of chain transfer, and established use in synthesizing BBNs. ,− Using ROMP, R K can be easily controlled by varying the monomer-to-initiator ratio ( M / I ), with large M / I s producing longer R K s.…”