5-Hydroxymethylfurfural (HMF) is an important platform chemical derived from biomass. Tremendous efforts have been made to transform HMF into valuable chemicals for applications in biofuels, materials science, and pharmaceuticals. Here we report the conversion of HMF into 5-hydroxymethyl-2-vinylfuran (HMVF), a versatile adhesive. HMVF can bond to a variety of substrates, e.g. metal, glass, plastics and rubber, under heating or acid treatment at room temperature. Mechanistic studies show that the vinyl group undergoes free radical polymerization and the hydroxyl group dehydrates to form an ether linkage to crosslink HMVF under either heating or acid treatment. The bonding strength (τ) of HMVF cured by heating (h-HMVF) is close to that of Krazy Glue (Loctite 401, cyanoacrylate) and higher than that of white glue (Pattex No. 710, PVA) and Pattex PKME15C epoxy glue. The outstanding adhesive performance of HMVF is attributed both to the interaction of hydroxyl groups with substrates and crosslinking by etherification between hydroxyl groups. Similar to Krazy Glue, HMVF is also used in its monomer form, which eliminates the use of solvents. Cells show good adhesion on crosslinked HMVF, which makes HMVF a potential bio-adhesive.

•Controlled synthesis of carboxylic acid functionalized cellulose derivatives.•Efficient immobilization of cellulose derivatives on amine-functionalized silica gel.•Similar chiral recognition abilities between coated-type and immobilized CSPs.•High solvent compatibility for immobilized CSPs.Traditional cellulose-based chiral stationary phases (CSPs) are prepared by physically coating cellulose derivatives onto substrates and only compatible with a very limited range of solvents as the mobile phase. Therefore, chemical immobilization of cellulose derivatives onto silica gel has been efficiently applied to improve the solvent compatibility of cellulose-based CSPs. Here we developed a novel approach to homogeneously modifying cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC). A series of carboxylic acid functionalized CDMPCs (CC-Xs) with controlled amounts and randomly distributed carboxylic acid groups was synthesized. CC-Xs were effectively immobilized onto amine-modified silica gel to afford immobilized CSPs. Compared to coated-type CSPs, immobilized CSPs significantly improved the solvent compatibility while maintaining similar chiral recognition abilities, but the introduction of excessive functional groups led to a deteriorated performance for columns. Moreover, a commercial drug, atenolol, was also sufficiently separated on the immobilized CSPs.Download high-res image (169KB)Download full-size image

Directed self-assembly (DSA) of block copolymers (BCPs) on lithographically defined chemically nanopatterned surfaces (or chemical patterns) combines advantages of conventional photolithography and polymeric materials and shows promise for meeting a sufficiently inclusive set of manufacturing constraints for applications in semiconductors and data storage. DSA attracts attention from both academia and industry and tremendous progress has been achieved in the past decade. This review highlights the development of DSA with an emphasis on efforts toward the integration of block copolymer lithography into the current lithographic process for the fabrication of devices for integrated circuits and bit-patterned media.

We demonstrated here for the first time that the stereochemistry of polylactide (PLA) blocks affected the assembly behaviors of PS-b-PLA on chemical patterns. Two PS-b-PLA block copolymers, where the PLA block is either racemic (PDLLA) or left-handed (PLLA), were synthesized and directed to assemble on chemical patterns with a wide range of Ls/L0. PS-b-PDLLA was stretched up to 70% on chemical patterns, while PS-b-PLLA was only stretched by 20%. The assembly behavior of PS-b-PDLLA was different from AB diblock copolymer, but similar to that of ABA triblock copolymer. The high stretchability might be attributed to the formation of stereocomplexes in PDLLA blocks. Compared to ABA triblock copolymers, stereocomplexed diblock copolymers have much faster assembly kinetics. This observation provides a new concept to achieve large process windows by the introduction of specific interactions, for example, H-bonding, supramolecular interaction, and sterecomplexation, between polymer chains.

5-Hydroxymethylfurfural (HMF) is considered as a valuable platform chemical for fuels and chemical intermediates. Tremendous efforts have been made on the development of catalysts for the dehydration of saccharides to HMF with high conversion and selectivity. Here we reported a new solid acid, phosphoric acid doped polybenzimidazole (PA–PBI), for the dehydration of fructose to HMF with high selectivity (∼94%) at high fructose concentration (50 wt%) in a water–methyl isobutyl ketone (MIBK) biphasic system. PA–PBI was directly obtained by the one-pot polycondensation reaction and was very stable under harsh reaction conditions due to the strong acid–base interaction between PA and imidazole in PBI. PA–PBI was recycled to catalyze the dehydration of fructose four times without the loss of activity and could also catalyze a variety of disaccharides and polysaccharides to produce HMF. The high selectivity and the ease of recycling make PA–PBI a superior catalyst for the dehydration of saccharides to HMF.

Block copolymer lithography is emerging as one of the leading technologies for patterning nanoscale dense features. In almost all potential applications of this technology, control over the orientation of cylindrical and lamellar domains is required for pattern transfer from the block copolymer film. This review highlights the state-of-art development of brushes to modify the substrates to control the assembly behaviors of block copolymers in films. Selected important contributions to the development of self-assembled monolayers, polymer brushes and mats, and chemically patterned brushes are discussed.

•There are no reports on poly(amino acid)-grafted celluloses.•The micellar aggregates showed a tunable pH-responsive property.•The micellar disaggregated to form unimolecular micelles at high pH in diluted solutions.•These grafted celluloses had characteristic chiroptical properties.•They have potential applications in controlled drug release and high-performance liquid chromatography.Three amphiphilic poly(N-acryloyl-l-amino acid) grafted celluloses were prepared by RAFT polymerization of N-acryloyl-l-amino acid, where amino acid is alanine, proline or glutamic acid, onto cellulose backbones. The chemical structure and solution properties of the brush copolymers were characterized with FTIR, NMR and wide angle X-ray diffraction (WAXD). The thermal stability of the brush copolymers was estimated by thermal gravimetric analysis (TGA). Circular dichroism (CD) and specific rotation measurements confirmed that these grafted celluloses had characteristic chiroptical properties. The amphiphilic brush copolymers self-assembled into micelles in the aqueous solution as confirmed by transmission electron microscopy (TEM) and dynamic light scattering (DLS) analyses. The micellar aggregates showed a tunable pH-responsive property and disaggregated to form unimolecular micelles at higher pH in diluted solutions. The brush copolymers have potential applications in controlled drug release and high-performance liquid chromatography, and so forth.

Fabrication of chemical patterns by electron beam lithography or extreme ultraviolet interference lithography is either low-throughput or prohibitively expensive to practice at sub-50 nm feature dimension. Here we report a new high-throughput approach that combines the advantages of both graphoepitaxy and molecular transfer printing (MTP) to fabricating chemical patterns at low cost for directed assembly of block copolymers. In this new approach, a cylinder-forming block copolymer ternary blend film is directed to assemble on a topographic HSQ substrate with sub-Lo, where Lo is the natural period of the block copolymer, relief structures to increase the feature density by a factor of ∼20, the surface domain pattern is replicated using MTP to create 1:1 chemical pattern, and then a lamellae-forming block copolymer is directed to assemble on the chemical pattern to realize high-aspect ratio Manhattan type nanostructures. This combined strategy allows us to fabricate chemical patterns with feature dimension below the resolution limit of current lithographic tools.