Synthesis and Solvent Free DLP 3D Printing of Degradable Poly(Allyl Glycidyl Ether Succinate).

Digital light processing (DLP) printing forms solid constructs from fluidic resins by photochemically crosslinking polymeric resins with reactive functional groups. DLP is used widely due to its efficient, high-resolution printing, but its use and translational potential has been limited in some applications as state-of-the-art resins experience unpredictable and anisotropic part shrinkage due to the use of solvent needed to reduce resin viscosity and layer dependent crosslinking. Herein, poly(allyl glycidyl ether succinate) (PAGES), a low viscosity, degradable polyester, was synthesized by ring opening copolymerization and used in combination with degradable thiol crosslinkers to afford a solvent free resin that can be utilized in DLP printing. Varying resin formulations of PAGES polymer are shown to decrease part shrinkage from 14% to 0.3%. Photochemically printed parts fabricated from PAGES possess tensile moduli between 0.43 and 6.18 MPa and degradation profiles are shown to vary between 12 and 40 days under accelerated conditions based on degree of polymerization and crosslink ratio.

Digital Light Processing to Afford High Resolution and Degradable CO2-Derived Copolymer Elastomers.

Vat photopolymerization 3D printing has proven very successful for the rapid additive manufacturing (AM) of polymeric parts at high resolution. However, the range of materials that can be printed and their resulting properties remains narrow. Herein, we report the successful AM of a series of poly(carbonate-b-ester-b-carbonate) elastomers, derived from carbon dioxide and bio-derived ϵ-decalactone. By employing a highly active and selective Co(II)Mg(II) polymerization catalyst, an ABA triblock copolymer (Mn=6.3 kg mol-1, ÐM=1.26) was synthesized, formulated into resins which were 3D printed using digital light processing (DLP) and a thiol-ene-based crosslinking system. A series of elastomeric and degradable thermosets were produced, with varying thiol cross-linker length and poly(ethylene glycol) content, to produce complex triply periodic geometries at high resolution. Thermomechanical characterization of the materials reveals printing-induced microphase separation and tunable hydrophilicity. These findings highlight how utilizing DLP can produce sustainable materials from low molar mass polyols quickly and at high resolution. The 3D printing of these functional materials may help to expedite the production of sustainable plastics and elastomers with potential to replace conventional petrochemical-based options.

Reassessing Undergraduate Polymer Chemistry Laboratory Experiments for Virtual Learning Environments.

Chemistry laboratory experiments are invaluable to students' acquisition of necessary synthetic, analytical, and instrumental skills during their undergraduate studies. However, the COVID-19 pandemic rendered face-to-face (f2f), in-person teaching laboratory experiences impossible from late 2019-2020 and forced educators to rapidly develop new solutions to deliver chemistry laboratory education remotely. Unfortunately, achieving learning and teaching objectives to the same caliber of in-person experiments is very difficult through distance learning. To overcome these hurdles, educators have generated many virtual and remote learning options for not only foundational chemistry courses but also laboratory experiments. Although the pandemic challenged high-level chemistry education, it has also created an opportunity for both students and educators to be more cognizant of virtual learning opportunities and their potential benefits within chemistry curriculum. Irrespective of COVID-19, virtual learning techniques, especially virtual lab experiments, can complement f2f laboratories and offer a cost-efficient, safe, and environmentally sustainable alternative to their in-person counterparts. Implementation of virtual and distance learning techniques-including kitchen chemistry and at-home laboratories, prerecorded videos, live-stream video conferencing, digital lab environment, virtual and augmented reality, and others-can provide a wide-ranging venue to teach chemistry laboratories effectively and encourage diversity and inclusivity in the field. Despite their relevance to real-world applications and potential to expand upon fundamental chemical principles, polymer lab experiments are underrepresented in the virtual platform. Polymer chemistry education can help prepare students for industrial and academic positions. The impacts of polymers in our daily life can also promote students' interests in science and scientific research. Hence, the translation of polymer lab experiments into virtual settings improves the accessibility of polymer chemistry education. Herein, we assess polymer experiments in the emergence of virtual learning environments and provide suggestions for further incorporation of effective polymer teaching and learning techniques into virtual settings.

Controlled Transdermal Delivery of Dexamethasone for Pain Management via Photochemically 3D-Printed Bioresorbable Microneedle Arrays.

Microneedle array patches (MAPs) are extensively studied for transdermal drug delivery. Additive manufacturing enables precise control over MAP customization and rapid fabrication. However, the scope of 3D-printable, bioresorbable materials is limited. Dexamethasone (DXM) is widely used to manage inflammation and pain, but its application is limited by systemic side effects. Thus, it is crucial to achieve high local drug concentrations while maintaining low serum levels. Here, poly(propylene fumarate-co-propylene succinate) oligomers are fabricated into DXM-loaded, bioresorbable MAPs via continuous liquid interface production 3D printing. Thiol-ene click chemistry yields MAPs with tailorable mechanical and degradation properties. DXM-loaded MAPs exhibit controlled elution of drug in vitro. Transdermal application of DXM-loaded MAPs in a murine tibial fracture model leads to substantial relief of postoperative pain. Pharmacokinetic analysis shows that MAP administration is able to control pain at a significantly lower dose than intravenous administration. This work expands the material properties of 3D-printed poly(propylene fumarate-co-propylene succinate) copolyesters and their use in drug delivery applications.