2D Fabrication of Tunable Responsive Interpenetrating Polymer Networks from a Single Photoresist

Abstract

Light-induced curing of photoresists is a well-established technique to fabricate polymer networks with precise control over the material properties. Herein, control is exerted over network material properties of a single polymer blend through the spatiotemporally controlled incorporation of secondary polymer networks resulting in interpenetrating polymer networks (IPNs). Light gated control over materials properties of IPNs is assessed theoretically by applying the general rule of mixture and experimentally by using a multifunctional polymer resist. The full IPNs are formed through covalent bonds, based on photocuring of the complementary photoreactive groups o-methyl benzaldehyde (UV light) and styrylpyrene (visible light). Applied to a spin coated polymer blend of UV light curable responsive poly(4vinylpyridine) (P4VP) and visible light curable poly(methyl methacrylate) (PMMA), the developed platform technology not only affords spatial control over the curing of the pH-swellable P4VP component from the polymer blend, but also allows adjustment of the extent of swelling by forming an IPN through subsequent curing of the PMMA component. Gated only by light irradiation of a polymer blend, it is possible to control IPN formation in 2D structures, which precisely adjusts the swelling behavior of the respective materials segments.

Additives for Ambient 3D Printing with Visible Light

“…[11][12][13] Relative to UV light, visible light is naturally abundant, less expensive, and benign (generally reduced absorption and scattering), which gives it the potential to advance 3D printing of polymeric materials by enabling economical preparation of, for example, cell-laden hydrogels, [14] opaque composites, [15] or multimaterial structures (via wavelength selective reactions). [7,[16][17][18][19] Recently, we demonstrated that a three component photosystem comprising a visible-light-absorbing photoredox catalyst (PRC) with donor (diphenyliodonium) and acceptor (triphenyl (n-butyl) borate) co-initiators could facilitate photocuring of acrylate-based resins on timescales (approximately seconds) that were competitive with commercial UV light systems (Figure 1). [11] However, the difference in mechanism undergone by UV photoinitiators (PIs) (Type I) and visible PRCs (Type II) to generate reactive radicals results in greater oxygen sensitivity for the latter.…”

Intelligent Polymers, Fibers and Applications

“…Distinguished from other multipolymer combinations, IPNs are stable in solvents with suppressed creep and flow [ 147 ] and are thus suitable for biomedical applications, damping materials, tough and impact-resistant materials, etc. Some examples include light-gated control [ 148 ], greener extraction [ 149 ], increased robustness [ 150 ] and organic photovoltaic inks [ 151 ].…”

Wavelength‐Selective Softening of Hydrogel Networks

“…Our group has pioneered the concept of wavelength orthogonal reactions in soft matter materials. [ 34–38 ] In particular, one of the systems contains a styrylpyrene group, which can undergo dimerization by visible light (405 nm) and dissociation by UV light. [ 36,39 ] Styrylpyrene can be applied in conjunction with an acrylamidylpyrene, having a highly redshifted activation wavelength of up to 490 nm.…”