Join RadTech

September 16-19, 2025 • Boulder, Colorado

TECHNICAL PROGRAM

Friday, September 19

Parallel Sessions, 8:30 – 10:00 AM

TRACK 1 (Rm: SEEC C120)
TRACK 2 (Rm: SEEC S372 A/B)

8:30 - 8:55

Molecularly engineered, light-responsive building blocks for the creation of well-defined bioinspired cellular microenvironments
April Kloxin, University of Delaware
Photopolymerization of Liquid Crystalline Phases for Structurally Programmed Optical Materials
Timothy White, University of Colorado Boulder

8:55 - 9:20

TBD
Stephanie Bryant, University of Colorado Boulder
Development of polyamide in photo-curable materials
Chen Wang, University of Utah

9:20 - 9:40

Kinetic Control of Photochemical Reactions Enables the Fabrication of Reprogrammable Gels
Manuela Garay-Sarmiento, University of Colorado Boulder, BioFrontiers
Effect of Functional Groups on Acrylate Photopolymerization Kinetics during UV Cure
Robin Crownover, US Army DEVCOM AC

9:40 - 10:00

Break
Break

Plenary Sessions, 10:00 AM – 12:30 PM

10:00 - 10:30

Type III Photopolymerization as a new Paradigm for Light-Based 3D Printing
Zachariah Page, The University of Texas at Austin

10:30 - 11:00

Arts and crafts by photopolymerization: programming complex actuation in liquid crystalline elastomers
Tayler Hebner, Purdue University

11:00 - 11:30

Design and Properties of Controlled Liquid Crystal Elastomer Networks
Emily Davidson, Princeton University

11:30 - 12:00

Photo-responsive Dynamic Networks
Stuart Rowan, University of Chicago

12:00 - 12:30

Dithiolane (Co)polymers and Their Potential Applications
Christopher Bowman, University of Colorado Boulder

Lunch, 12:30 – 1:30 PM

Join Radtech
Subscribe to RadTech News

RadTech International North America | The Association for Ultraviolet and Electron Beam Technologies
6935 Wisconsin Ave, Suite 207, Chevy Chase, MD 20815 | (240) 497-1242 | uveb@radtech.org

Copyright ©2026 RadTech International. All rights reserved.     Website development by The Creative Development Group.

Molecularly engineered, light-responsive building blocks for the creation of well-defined bioinspired cellular microenvironments

April Kloxin, University of Delaware

The microenvironments of cells in the human body are known to direct cellular responses, including in healthy versus maladaptive wound healing upon injury. Accordingly, soft materials are being designed are inspired by these microenvironments, particularly the extracellular matrix (ECM) that surrounds cells, for probing and controlling cellular responses both in vitro and in vivo, from controlled multidimensional culture models for mechanistic studies to injectable materials for therapeutic delivery. In this talk, I will highlight some of our recent efforts in this arena. For example, through the design of molecularly engineered polymer and peptide building blocks, we have established synthetic ECMs that allow us to probe the response of barrier tissue cells (e.g., epithelial cells, fibroblasts, immune cells) to injury triggered upon the application of light or other stimuli. Integration of physically assembling peptides within such covalently crosslinked networks further imparts designed hierarchical, bioactive nano- and micro-structures and physiologically relevant viscoelasticity. We collaboratively are using bioprinting for the creation of well-defined 3D cultures built upon such materials with high-throughput for the evaluation of therapeutic approaches. Additionally, we are utilizing these types of bottom-up, molecularly engineered synthetic ECMs in conjunction with top-down, flow-based systems for the production of injectable delivery vehicles and cell-based therapies.

Photopolymerization of Liquid Crystalline Phases for Structurally Programmed Optical Materials

Timothy White, University of Colorado Boulder

The self-organizing behavior of liquid crystalline phases offers a powerful framework for fabricating optical materials with periodic structures on the scale of visible and near-infrared light. In this presentation, I will describe photopolymerization-based strategies to prepare solid-state optical elements from cholesteric and blue phase liquid crystals, as well as nematic phases patterned via photoalignment. These materials exploit the intrinsic periodicity and birefringence of liquid crystalline order to produce reflection, diffraction, and polarization-selective properties in thin, photopolymerized films. Cholesteric liquid crystals, with their helical supramolecular organization, serve as tunable Bragg reflectors whose reflection bandwidth, handedness, and angular response can be precisely controlled through composition and polymerization conditions. Blue phase liquid crystals, which form three-dimensional cubic structures with nanoscale periodicity, offer isotropic yet diffractive behavior suitable for fast-switching photonic applications. Additionally, photoalignment of nematic phases provides a route to encode spatially varying director fields prior to polymerization, enabling the fabrication of polarization gratings and other diffractive optical elements with high fidelity. Emphasis will be placed on UV-curable reactive mesogens and polymer-stabilization strategies that lock in delicate liquid crystal architectures while preserving their optical function. These approaches support scalable, mask-based fabrication of flat, flexible, and responsive optical films. The resulting photopolymerized materials have applications in reflective displays, laser beam shaping, AR/VR optics, and tunable filters—highlighting the role of photopolymerization as a tool for translating soft molecular order into robust optical function.

TBD

Stephanie Bryant, University of Colorado Boulder

Development of polyamide in photo-curable materials

Chen Wang, University of Utah

Photopolymers are ubiquitous materials for coatings, adhesives, 3D printing, and many other rapidly growing applications. Today’s photopolymer market is calling for improved materials performance, as well as enhanced sustainability such as adopting renewable chemicals. In this talk, we demonstrate amides as a performance-advantaged functional group over urethanes, in the design of rapidly photopolymerizable resins. Our crosslinked polyamides synthesized from step-growth photopolymerization exhibited high toughness, e.g. >100% elongation-at-break, > 1GPa Young’s modulus, and >40 MPa tensile yield strength, a performance typically only attainable from semicrystalline thermoplastics. Further, we discuss achieving semicrystallinity in the network photopolymers. By incorporating amide groups and hydrogen bonding, the enhanced backbone rigidity raised glass transition temperatures by 35-40 °C compared to a polyester control group. In the crystalline domain, the hydrogen bonding raised equilibrium melting temperatures by 60 °C, but reduced melting enthalpy. We also find that hydrogen bonding did not alter the threshold of chain length between crosslinks for crystallization (>2,500 g/mol).

Kinetic Control of Photochemical Reactions Enables the Fabrication of Reprogrammable Gels

Manuela Garay-Sarmiento, University of Colorado Boulder, BioFrontiers

Native tissues undergo dynamic changes in shape and mechanical properties, particularly during tissue development and disease progression. Gels capable of recapitulating such dynamic properties (e.g., local stiffness, shape morphology) are gaining significant interest to understand and guide cellular behavior. Light-responsive materials are of particular interest since light can be delivered remotely and with high precision, enabling spatiotemporal control during reprogramming. Furthermore, Digital Light Processing (DLP) has emerged as a promising technique to fabricate gels with complex 3D structures that more accurately mimic the structural complexity and heterogeneity of native tissues. To avoid consumption of photosensitive groups during DLP printing, we leverage the kinetic specificity of methacrylate homopolymerizations and dithiolane (DL)-ene reactions. This allows the formation of objects from photoreactive resins via DLP with methacrylate crosslinking and preservation of photoresponsive DL groups for subsequent light-based stiffening on demand. DLP printed gels can be reproducibly post stiffened up to 10-fold, dynamically replicating the mechanical properties of a broad range of healthy and diseased tissues. Such precise spatial control over stiffness enables the creation of complex shape transformations—such as bending and twisting—based on how the stiffness gradients are designed across the material. Importantly, the post stiffening process occurs under mild conditions, without the need for photoinitiators or high light intensities, making it ideal for future live-cell studies and advanced mechanobiology applications.

Effect of Functional Groups on Acrylate Photopolymerization Kinetics during UV Cure

Robin Crownover, US Army DEVCOM AC

It has been previously shown that monoacrylate secondary functionalities have a profound effect on the photopolymerization kinetics of these materials. While the previous research showed a polymerization rate increase with the addition of specific secondary functionalities, we have identified alternative secondary functionalities that reduce the polymerization kinetics. Based on their electron density and degree of electronegativity, it would be expected that these functional groups would have increased photopolymerization rates. This study therefore investigates these functional groups in comparison with other well-studied functional groups in an attempt to understand the mechanistic reasons these functional groups reduce photopolymerization kinetics. By slowing photoinitiation, all differences in photopolymerization rates are exaggerated, allowing for subtle differences in kinetics to be observed and further insight into the effects of the functional groups on polymerization to be seen. In addition to comparing ethyl spaced functional groups, the spacing between the acrylate group and secondary functionality was increased, which further slowed polymerization rate to a degree beyond what was expected from other functional groups.

Type III Photopolymerization as a new Paradigm for Light-Based 3D Printing

Zachariah Page, The University of Texas at Austin

Light has revolutionized the creation of polymers, enabling groundbreaking technologies in imaging, lithography, adhesives, and 3D printing. Its effectiveness stems from the unmatched precision in controlling chemical reactions both in time and space. Traditional methods, however, rely on high-energy ultraviolet (UV) light (wavelengths below 400 nm), which is ubiquitously absorbed and scattered, which can lead to degradation and a loss in spatial resolution. These issues limit the range of materials compatible with UV-based polymer creation techniques. Excitingly, the recent commercialization of affordable light emitting diodes (LEDs) has paved the way for exploring gentler, visible light-triggered reactions in polymer production. This presentaton will focus on how the ZAP Research Group has contributed to the development of rapid photopolymerization chemistry from a fundamnetal perspective. The discussion will cover the “evolution” of visible light-induced polymerizations from the following mechanisms: 1) Type I: One component photoinitiation РDirect light absorption leading to bond scission to 2) Type II: Two component photo-redox catalysis РLight-driven electron transfer processes and finally 3) Type III: Three component triplet fusion upconversion РConverting lower-energy photons to higher-energy ones. One of our primary objectives with these processes is to enable projection-based 3D printing that require rapid photopolymerizations (curing in less than 60 seconds), good shelf stability in the absence of light (temporal control), and high sensitivity to react with low-intensity LED exposure (less than 50 mW/cm²). These advancements aim to make visible light polymerization more practical, efficient, and widely applicable in various industries.

Arts and crafts by photopolymerization: programming complex actuation in liquid crystalline elastomers

Tayler Hebner, Purdue University

Liquid crystalline elastomers (LCEs) are stimuli-responsive polymers that are often programmed to undergo reversible, large-magnitude deformations. The deformations exhibited by these materials are a result of an order disruption between liquid crystalline mesogens incorporated in the polymer network. Programming complex modes of deformation in LCEs requires patterning of the alignment of the liquid crystalline mesogens, and crosslinks in the polymer network are often used to retain this alignment in the freestanding LCE. Notably, the properties of the crosslinked network are also correlated to actuation properties such as phase transition temperatures and deformation magnitude. Therefore, control of network topology in the crosslinking step enables control over the functional properties of the LCE. As such, photopolymerization is often used as a crosslinking step in LCE fabrication as it enables spatiotemporal control and many combinations of initiator and monomer components are available to tune final network structure. In this work, we specifically focus on thiol-acrylate photopolymerization for crosslinking in LCEs, which produces networks with pendant thiol groups and creates opportunities for post-functionalization of the material. We demonstrate that a secondary spatially-controlled photopolymerization step that leverages these pendant thiols enables patterning of complex deformations based on spatial discrepancies in crosslink density. In another instance, we show that secondary photopolymerization leveraging the pendant thiols enables lamination of LCEs with contrasting properties to produce snap-through actuation. Overall, these studies demonstrate that fundamental understanding and control over network formation via photopolymerization are powerful tools for complex and creative programming of LCE actuators.

Design and Properties of Controlled Liquid Crystal Elastomer Networks

Emily Davidson, Princeton University

We study a series of liquid crystal elastomers photopolymerized from precursor oligomers to understand the coupling between LCE network structure and material properties. The results elucidate the intrinsic competition that arises between network composition and crosslink density in tuning the nematic-to-isotropic transition temperatures of these materials. We also examine how both the sharpness of the transition and soft elasticity are controlled by the structure of the network itself. Finally, we examine networks polymerized from fractionated liquid crystalline oligomers with narrow molecular weight distributions.

Photo-responsive Dynamic Networks

Stuart Rowan, University of Chicago

The dynamic bond can be defined as any class of bond that selectively undergoes reversible breaking and reformation, usually under equilibrium conditions. The incorporation of dynamic bonds (which can be either covalent or non-covalent) allows access to structurally dynamic polymers and composites. These materials can exhibit macroscopic responses to environmental stimuli due to the rearrangement of their polymeric architecture. The nature of the dynamic bond not only determines the stimulus the material responds to but also influences the response itself. This design concept represents a molecular-level approach to developing new stimuli-responsive/adaptive materials. We have been exploring photo-responsive dynamic bonds to access new material platforms and have developed a range of mechanically stable, structurally dynamic polymer and nanocomposite films that change their properties in response to light. These adaptive materials have potential applications in healable plastics, responsive liquid crystalline polymers, adhesives, chemical sensors, shape memory materials, and ion conducting systems. Our latest results in these areas will be discussed.

Dithiolane (Co)polymers and Their Potential Applications

Christopher Bowman, University of Colorado Boulder

As additive manufacturing technologies continue to advance, the challenge of recycling printed components persists. Crosslinked polymers remain the material of choice in light-based additive manufacturing due to their fast gelation kinetics and shape stability after crosslinking. However, their permanently crosslinked structure hinders recycling or remolding unless dynamic bonds are present. Covalent adaptable networks (CANs) address this limitation through the incorporation of dynamic bonds at the crosslinks, enabling facile reprocessability. Recently, 1,2-dithiolanes, a five-membered cyclic disulfide, have emerged as a promising dynamic chemistry in polymer. Dithiolanes undergo a ring-opening polymerization, resulting in linear disulfides and enabling the formation of dynamic bonds directly through the crosslinking reaction. Here, we introduce a tetrafunctional dithiolane monomer, lipoic acid pentaerythritol ethoxylate, which can be photopolymerized and is compatible with high-resolution light-based additive manufacturing across multiple length scales. Additionally, this monomer can depolymerize back to its original ring-closed form through heating and solvent dilution, allowing for repolymerization. Furthermore, through a post-polymerization disulfidation reaction with a monofunctional vinyl, the dynamic character of these materials can be modulated. This work represents an advancement in the development of multifunctional dithiolane monomers and recyclable resins for additive manufacturing.