title: Thick, three-dimensional nanoporous density-graded materials formed by optical exposures of photopolymers with controlled levels of absorption.
abstract: Three-dimensional (3D) intensity distributions generated by light passing through conformal phase masks can be modulated by the absorption property of photosensitive materials. The intensity distributions have extremely long depth of focus, which is proportional to the size of the phase masks, and this enables one to pattern thick (approximately 100 microm), nanoporous structures with precise control of grade density. Various density-graded 3D structures that result from computational modeling are demonstrated. Results of x-ray radiograph and the controlled absorption coefficient prove the dominant mechanism of the generated graded density is absorption of the photosensitive materials. The graded-density structures can be applied to a chemical reservoir for controlled release of chemicals and laser target reservoirs useful to shape shockless wave compression.
authors.affiliation: Department of Materials Science and Engineering, University of Illinois at Urbana Champaign, 1304 Green Street, Urbana 61801, USA.
authors.forename: Yun-Suk
authors.initials: YS
authors.lastname: Nam
authors.forename: Seokwoo
authors.initials: S
authors.lastname: Jeon
authors.forename: Daniel Jay-Lee
authors.initials: DJ
authors.lastname: Shir
authors.forename: Alex
authors.initials: A
authors.lastname: Hamza
authors.forename: John A
authors.initials: JA
authors.lastname: Rogers