Thiol–ene “click” reactions and recent applications in polymer and materials synthesis: a first update

Recent advances in vegetable oil-based polymers and their composites

Renewable polymeric materials from vegetable oils: A perspective

Architecture, self-assembly and properties of well-defined hybrid polymers based on polyhedral oligomeric silsequioxane (POSS)

POSS are nano-sized stable 3-dimensional architectures which consist of alternate Si–O bonds to form cage structures with Si atoms as vertices. The mono- or multi-functional POSS could be prepared through modification of their reactive organic functional groups attached in the vertex positions. Depending on the structure and reactivity of those vertex groups, POSS are allowed to be introduced into virtually any existing polymer systems. This review paper summarizes the recent development on the preparation and properties of POSS-containing polymers. In addition, this review paper also gives an overview of the recent development in the area of a wide range of POSS-based composite systems for a variety of applications including fluorescence sensors, liquid crystals, photoresist materials, low dielectric constant materials, organic semiconductors, energy-related materials, drug and gene delivery systems, coating materials and special rubber materials.

Polyhedral oligomeric silsesquioxane-based hybrid materials and their applications

A novel hybrid resist for UV nanoimprint lithography (UV-NIL) based on the thiol–ene photopolymerization is presented. Our system comprises mercaptopropyl polyhedral oligomeric silsesquioxane and benzyl methacrylate, with trimethylolpropane trimethacrylate as the crosslinker. The obtained hybrid resists possess a variety of characteristics desirable for UV-NIL, such as low viscosity (6.1–25 cP), low bulk-volumetric shrinkage (5.3%), high Young's modulus (0.9–5.2 GPa), high thermal stability, and excellent dry-etch resistance. Based on these performances, the optimized components are evaluated as UV-NIL resists. The result is a high-resolution pattern with feature sizes in the range of 100 nm to several microns. The double-layer resist approach is used for pattern transfer into silicon substrates. The excellent oxygen-etch resistance of the barrier material enables a final transfer pattern that is about three times higher than that of the original NIL mold.

A Nanoimprint Lithography Hybrid Photoresist Based on the Thiol–Ene System

We demonstrate here a series of hybrid materials based on thiol-contained polyhedral oligomeric silsesquioxane (POSS-OA/SH) and acrylated caster oil (ACO), which can be photo-cured through “thiol-ene” reaction. The fast photo-crosslinking reaction between POSS and ACO was traced by FT-IR, which is insensitive to oxygen gas. Compared with the pure ACO, the hybrid component of POSS-OA/SH and ACO exhibited much faster photo-cured speed upon the exposure of UV-light. The obtained hybrid materials were transparent to visible light and no obvious phase-separation was observed. AFM and SEM demonstrated that POSS nanoparticles were well-dispersed in the ACO matrix without obvious aggregation even if the content of POSS is higher than 60%. The introduction of POSS can decrease the surface energy of the obtained hybrid materials. The thermal stability of the obtained hybrid materials increased with the increase of POSS content. These characteristics gave the obtained hybrid material potential application in coating, and these studies provided a novel alternative approach to prepare the hybrid materials from the renewable source.

“Thiol-ene” photo-cured hybrid materials based on POSS and renewable vegetable oil

Functional polyhedral oligomeric silsesquioxane (POSS)-based materials have been developed as an ideal material with high performance for nanoimprint lithography (NIL). A novel fluorinated hybrid resist as a soft mold for NIL, based on thiol-ene photopolymerization, was precisely designed and synthesized and is comprised of fluorinated mercaptopropyl polyhedral oligomeric silsesquioxane (POSS-F-SH) and a diluted crosslinker (2,2,3,3,4,4,5,5-octafluoro-1,6-hexyl diacrylate, DCFA4). The obtained fluorinated hybrid resists possess a variety of characteristics desirable for UV-NIL, including low viscosity (16–239 cP), a low bulk volumetric shrinkage (4.8–7.5%) and a good resistance to oxygen inhibition. The cross-linked hybrid resins exhibited high transparency to UV light and resistance to organic solvents. As a soft mold, the excellent mechanical property (Young's modulus: 0.31–1.56 GPa) and low surface energy (14–20.4 mJ m−2) of the fluorinated polymers provide a clean mold release without fracture or deformation of the embossed structures. The thermally stability (Td > 300 °C) render them capable of being used for both UV and thermal NIL duplication processes. The resultant soft mold exhibited a high resolution patterning capacity with feature sizes in the range of 200 nm to several microns. The economic efficiency of the mold fabrication, as well as the high durability and excellent releasing properties, could be quite valuable in NIL for the high-throughput fabrication of nano-devices.

A “thiol-ene” photo-curable hybrid fluorinated resist for the high-performance replica mold of nanoimprint lithography (NIL)

We designed a novel photoreversible resist for UV-NIL that comprises a photoreversible cross-linker (2-[(4-methyl-2-oxo-2 h-1-benzopyran-7-yl)oxy] ethyl ester, AHEMC). Under exposure of 365 nm UV light, this photoreversible resist can form a cross-linked network via radical polymerization of acrylate groups and photodimerization of coumarin moieties. The formed polymer networks containing coumarin dimer moieties could be degraded via illumination of point light source (254 nm). The reversibility of cross-linked system was helpful to refresh mold easily and release the adhered curing resist at room temperature.

Photoreversible Resists for UV Nanoimprint Lithography (UV-NIL)

The invention relates to a sulfydryl-containing low polysiloxane compound, an ultraviolet photoresist composition thereof, and an impressing process and belongs to the technical field of micronano processing. The sulfydryl-containing low polysiloxane compound is shown as a general formula (1). The ultraviolet photoresist composition has low contractibility, low viscosity and high oxygen etching resistance. The general formula (1) is (SiO1.5R1)m.(SiO1.5R2)n (1), wherein R1 is -CH2-CH2-CH2-SH; R2 is non-substitute alkyl or alkyl substituted by a substituent, non-substitute aryl or aryl substituted by a substituent and non-substitute alkoxy or alkoxy substituted by a substituent; the substituent is halogen; m is an integer from 3 to 12; and n is an integer from 0 to 12.

Hong Lin

Papers

A Nanoimprint Lithography Hybrid Photoresist Based on the Thiol–Ene System

“Thiol-ene” photo-cured hybrid materials based on POSS and renewable vegetable oil

A “thiol-ene” photo-curable hybrid fluorinated resist for the high-performance replica mold of nanoimprint lithography (NIL)

Photoreversible Resists for UV Nanoimprint Lithography (UV-NIL)

Sulfydryl-containing low polysiloxane compound, ultraviolet photoresist composition thereof, and impressing process