Efficient Surface Neutralization and Enhanced Substrate Adhesion through Ketene Mediated Crosslinking and Functionalization

Abstract

Balancing the interfacial interactions between a polymer and substrate is one of the most commonly employed methods to ensure the vertical orientation of nanodomains in block copolymer lithography. Although a number of technologies have been developed to meet this challenge, there remains a need for a universal solution for surface neutralization that combines simple synthesis, fast processing times, generality toward substrate, low density of film defects, and good surface adhesion. The chemistry of ketenes, which combines highly efficient polymer crosslinking through dimerization and surface adhesion through reaction with the substrate, is shown to be well suited to the challenge. The versatile chemistry of ketenes are accessed through the post‐polymerization of Meldrum's acid, which can be easily incorporated into copolymers through controlled radical polymerization processes. Further, the Meldrum's acid monomer is synthesized on a large scale in one step without the need for chromatography. Processing times of seconds, low defect density, simple synthetic procedures, and good substrate adhesion make these materials attractive as robust block copolymer neutralization layers.

Cross-Linkable and Self-Foaming Polysulfide Materials for Repairable and Mercury Capture Applications

“…As what discussed above and reported in the literature, − thermolysis of MA moieties generates highly reactive ketene groups for further addition reactions with evolves of CO 2 and acetone molecules. The reaction routes have been applied to preparation of a new class of thermosetting resins. , In this work, we explore the first example of utilization of the evolved CO 2 as the gas source for self-foaming MA-based cross-linked resins. The self-foaming feature of poly­(S-MA-St) has been demonstrated.…”

Perpendicularly Oriented Block Copolymer Thin Films Induced by Neutral Star Copolymer Nanoparticles

“…From 1 H NMR spectra of arm 3–7 and star 3–7, it was found that the molar ratio of styrene/MMA in arm 3–7 was 38:62, while the molar ratio of (styrene + DVB)/MMA in star 3–7 was 59:41 and it is different from the feed ratio (Figure S5). In this case, the phenyl protons from polyDVB core showed a weak and broad peak shown from 6 to 8 ppm in 1 H NMR spectrum due to the partial immobilization of the cross-linked polyDVB in the star core. , The value of 59:41 from 1 H NMR of star 3–7 is consistent with the neutral composition of PS- r -PMMA random copolymers. − …”

Interface Manipulations Using Cross-Linked Underlayers and Surface-Active Diblock Copolymers to Extend Morphological Diversity in High-χ Diblock Copolymer Thin Films

“…This is in stark contrast to, e.g., the self-assembly of cylinder-forming PS- b -PMMA thin films, where the chemical composition of the underlayers affords the control of the orientation of the PMMA cylinders without any change of morphology. These initial results on cross-linked underlayers further hint at the need to precisely adjust the interfacial energy at the top interface to promote the formation of out-of-plane microdomains of PS- b -MH. − …”

“…Taking inspiration from earlier strategies to control the surface properties of planar substrates using cross-linked copolymer mats either made from comonomers representative of the BCP blocks, − or from a single monomer with varying amounts of a cross-linkable comonomer, we have synthesized four different photo-cross-linkable statistical copolymers PN n A p (with n and p the mol % of 4-vinylbenzyl azide and AGA units, respectively, Figure ). First, a PS-based copolymer was obtained in two steps by reversible addition-fragmentation chain transfer (RAFT) copolymerization of p -chloromethyl styrene 1 and styrene 2 using 3 as a chain transfer agent (CTA), followed by an azidation reaction in order to generate the photo-cross-linkable azidomethyl units.…”