Transient laser heating induced hierarchical porous structures from block copolymer–directed self-assembly

Abstract

Development of rapid processes combining hierarchical self-assembly with mesoscopic shape control has remained a challenge. This is particularly true for high-surface-area porous materials essential for applications including separation and detection, catalysis, and energy conversion and storage. We introduce a simple and rapid laser writing method compatible with semiconductor processing technology to control three-dimensionally continuous hierarchically porous polymer network structures and shapes. Combining self-assembly of mixtures of block copolymers and resols with spatially localized transient laser heating enables pore size and pore size distribution control in all-organic and highly conducting inorganic carbon films with variable thickness. The method provides all-laser-controlled pathways to complex high-surface-area structures, including fabrication of microfluidic devices with high-surface-area channels and complex porous crystalline semiconductor nanostructures.

Direct synthesis of graphitic mesoporous carbon from green phenolic resins exposed to subsequent UV and IR laser irradiations

“…6d). This may be related to the fast phenolic resin/template carbonization under CO 2 irradiation leading to the formation and release of CO x , H 2 O and H 2 gaseous species and consequently to the pore expansion31. The surface area is 43 m 2 ∙g −1 and the porous volume 0.11 cm 3 ∙g −1 , lower than the carbon materials obtained by UV (Table 1).…”

“…Carbon-encapsulated magnetic nanoparticles were synthesized by laser irradiation with a pulsed Nd:YAG laser (355 nm) of a solution containing various metalocenes dissolved in xylene at room temperature and atmospheric pressure28. More recently, supported nanostructured carbons (porous carbons, graphenes, and carbon nanocomposites) prepared by CO 2 laser has been reported as well29303132. The laser approach operates generally in air or inert atmosphere, at room temperature and provides localized high temperatures difficult to achieve by conventional thermal annealing, therefore, converting organic polymers into carbon materials in short time experiments.…”

KOH-activated graphite nanofibers as CO2adsorbents

“…These changes are increasingly viewed as a threat to both the global economy and the natural environment [1][2][3][4]. This increase in CO 2 is mainly attributed to human activities [5][6][7][8][9][10].…”

Giant Gyroid and Templates from High-Molecular-Weight Block Copolymer Self-assembly

“…Along with structural development, a well-defined gyroid structure displaying long-range order was finally achieved over a large area, after formation of a cylindrical structure at an early stage. Unlike other studies emphasizing the importance of 3D nanostructures for performance2425262728293031, only in a high-molecular-weight BCP system could we find an approach to compare the morphology-dependent transport and filtration characteristics of two different nanostructures, i.e., those with hexagonal and gyroid structures from a single material. We further demonstrated an inverse skeletal GYR replica using a pristine GYR morphology as a sacrificial template, as shown in Fig.…”

“…Wiesner and coworkers proposed various approaches to create porous and hierarchical structures using self-assembled BCP films2425. Sivaniah et al fabricated a perforated bicontinuous multilayer in sphere-forming BCP films, which were prepared through the osmotic shock with a selective solvent26.…”