3D printing of optical materials by processes based on photopolymerization: materials, technologies, and recent advances

Abstract

3D printing technologies have expanded beyond the research laboratories where they were used solely for prototyping and have become widely used in several industries. The production of custom 3D objects has significant potential in optical applications. However, this necessitates extremely specific material properties, such as transparency, homogeneity, birefringence, and surface finish. Currently, the majority of optical objects are manufactured using plastics. Moreover, the 3D printing processes using polymers to produce optical objects have significant advantages, such as limited wastage, short manufacturing time, and easy customization. However, despite extensive efforts, no technology has achieved the production of objects perfectly suited for optical applications. The objective of this review is to summarize recent advances in the field of 3D printing for optics, with an emphasis on specific developments for dedicated applications, and to explore new candidate processes.

Two‐Photon Polymerization Lithography for Optics and Photonics: Fundamentals, Materials, Technologies, and Applications

“…Conversely, polymerization with light has been widely investigated as photon-initiated crosslinking is conveniently triggered in many kinds of polymers suited for 3D printing, thus lifting the issues mentioned above. [34][35][36][37][38][39][40][41][42] However, the materials illuminated within the optical beam path will experience some degree of polymerization when using the one-photon absorption (OPA) process, leading to reduced resolution, making fabrication of arbitrary 3D structures impossible. [43][44][45][46][47][48][49][50][51] Conversely, bearing on the imaginary part of the third-order nonlinear susceptibility, the nonlinear process of two-photon absorption (TPA) is significantly different from OPA as the absorption cross section (ACS) is typically several orders of magnitude smaller than that of OPA.…”

Renewable Photopolymers: Transformation of Biomass Resources into Value-Added Products Under Light

“…Compared to a thermocuring process, curing with light exhibits many advantages including the absence of volatile organic compounds emissions, reduced energy consumption, compatibility with thermosensitive monomers or biological tissues, and spatiotemporal control of the cured area, to name but a few. 1−4 These advantages result in the applications of photocured products in a wide range of areas, such as dentistry, 5 automotive and optical equipments, 6 coatings, 7 shape memory polymers, 8 tissue engineering, 9−11 and 3D printing 12−17 or even 4D printing. 18,19 For almost a century, fossil resources play a crucial role not only in the energy sector but also as the primary carbon sources for the chemical industry.…”

“…4 2.4 48.3 31.9 -----Rapeseed 45 3.8 4.0 2.0 56.0 26.0 10.0 ----Sesame 45 3.9 9.0 6.0 41.0 43.0 1.0 ----Cottonseed 45 3.9 21.6 2.6 18.6 54.4 0.7 ----Corn 45 4.5 10.9 2.0 25.4 59. 6 1.2 ----Soybean 45 4 of products from PIs toward biological tissues. The reversibility of photocycloaddition also facilitates the design of reprogrammable materials.…”

“…The process is generally accompanied by fluid–solid phase transformation and changes in thermophysical properties for specific purposes. Compared to a thermocuring process, curing with light exhibits many advantages including the absence of volatile organic compounds emissions, reduced energy consumption, compatibility with thermosensitive monomers or biological tissues, and spatiotemporal control of the cured area, to name but a few. − These advantages result in the applications of photocured products in a wide range of areas, such as dentistry, automotive and optical equipments, coatings, shape memory polymers, tissue engineering, − and 3D printing − or even 4D printing. , …”

Recent advances on benzylidene ketones as photoinitiators of polymerization

“…Parallel to the polymerization efficiency, the ability of the photoinitiating system to bleach during the polymerization process is an important issue. [40,84,179,267,[281][282][283][284][285] Indeed, photobleaching can allow a better light penetration and thus improve the depth of cure. [286] This point is of crucial importance, notably in dentistry.…”