About

Thomas J. Wallin is a Research Professor in the Department of Materials Science and Engineering at MIT. His research focuses on advancing soft wearable devices, emphasizing their applications in human-computer interaction. His group combines materials, chemistry, advanced manufacturing, and mechanical design to develop new technologies aimed at enhancing the complexity and functionality of soft machines. Professor Wallin has extensive expertise in additive manufacturing and has explored the use of soft materials in 3D-printed devices, such as actuators and 'automatically perspiring soft robots' that utilize sweat as a cooling mechanism. He earned a BS in physics and chemistry from The College of William and Mary in 2010, and an MS and PhD in materials science and engineering from Cornell University in 2018. Prior to joining MIT, he was a research scientist in soft wearable technologies at Meta’s Reality Labs Research, which focuses on immersive technologies.

Research topics

• Computer Science
• Materials science
• Composite material
• Artificial Intelligence
• Nanotechnology
• Engineering
• Algorithm
• Biomedical engineering
• Mechanical engineering
• Structural engineering
• Electrical engineering
• Medicine

Selected publications

• Soft photo-ionotronics

  Nature Communications · 2026-02-21

  articleOpen accessSenior author

  The ability to control the movement of charged species in the circuitry of living beings and machines is essential for complex signal processing, computation, and, ultimately, higher functionality. We describe a class of photo-ion generators (PIGs) based on non-ionic photoacids that can create large (> 1000x) irreversible changes in ionic conductivity under illumination, depending on the PIG species, concentration, and solvent. Incorporation of PIGs into elastomers by simple swelling methods yields soft (60 kPa ≤ E ≤ 10 MPa), stretchable, photo-ionic gels (PIGels). The resolution of photo-patterned conductivity in PIGels is less than 1 cm and demonstrates stability over several days, suggesting utility in engineered devices. Leveraging the photo-responsive properties of these materials, we demonstrate high-sensitivity mechanical sensors via conductance changes ([∆G/G0]/σ = 20 MPa-1) and photo-writable, soft circuitry. Gel ionotronics are typically easy to prepare, but control of local ionic character is unusual. Here, the authors report the combination of elastomers with photo-ion generators for photopatterned control of conductivity in the gel materials.

  PublisherOA PDFDOI

• Soft Photo-Ionotronics

  ChemRxiv · 2026-02-16

  articleOpen accessSenior author

  The ability to control the movement of charged species in the circuitry of living beings and machines is essential for complex signal processing, computation, and, ultimately, higher functionality. We describe a class of photo-ion generators (PIGs) based on non-ionic photoacids that can create large (> 1000x) irreversible changes in ionic conductivity under illumination, depending on the PIG species, concentration, and solvent. Incorporation of PIGs into elastomers by simple swelling methods yields soft (60 kPa ≤ E ≤ 10 MPa), stretchable, photo-ionic gels (PIGels). The resolution of photo-patterned conductivity in PIGels is less than 1 cm and demonstrates stability over several days, suggesting utility in engineered devices. Leveraging the photo-responsive properties of these materials, we demonstrate high-sensitivity mechanical sensors via conductance changes ([∆ G / G 0 ]/σ = 20 MPa -1 ) and photo-writable, soft circuitry.

  PublisherOA PDFDOI

• Soft Photo-Ionotronics

  ChemRxiv · 2025-04-11

  preprintOpen accessSenior author

  The ability to control the movement of charged species in the circuitry of living beings and machines is essential for complex signal processing, computation, and, ultimately, higher functionality. We describe a class of photo-ion generators (PIGs) based on non-ionic photoacids that can create large (> 1000x) irreversible changes in ionic conductivity under illumination depending on the PIG species, concentration, and solvent. Incorporation of PIGs into polyurethane rubber by simple swelling methods yields soft (E > 2 MPa), stretchable, photo-ionic gels (PIGels). The resolution of photo-patterned conductivity in PIGels is less than 1 cm and demonstrates stability over several days, suggesting utility in engineered devices. Utilizing this novel class of material, we demonstrate high sensitivity mechanical sensors via conductance changes ([ΔG/G0]/σ = 20 MPa-1) and photo-writable, soft circuitry.

  PublisherOA PDFDOI

• Photopatternable, Degradable, and Performant Polyimide Network Substrates for E-Waste Mitigation

  ChemRxiv · 2024-05-01 · 2 citations

  preprintOpen access

  The continuous accumulation of electronic waste is reaching alarming levels necessitating sustainable solutions to mitigate environmental impact. Fabrication of the commercial electronic substrates also requires high heat. As an alternative, we propose a series of reprocessible electronic substrates based on photopolymerizable polyimides containing degradable ester linkages. We synthesize imide-containing diallyl monomers derived from readily available chemical feedstocks to produce high-quality substrates via rapid photopolymerization. Such materials possess exceptional thermal properties (thermal conductivity, K = 0.37-0.54 WmK-1; degradation temperature, Td > 300 °C), dielectric (dielectric constant, Dk = 2.81-3.05; dielectric loss, Df <0.024) and mechanical properties (Strength ~ 50 MPa ; ultimate elongation, dL/L0 > 5%) needed in flex electronic applications. When utilized as electronic substrates, we demonstrate mild depolymerization via transesterification reactions to recover and reuse the functional components. Moreover, these photopolymer resins remain compatible with commercial workflows and enable fabrication of next-generation, dense multilayered circuits.

  PublisherOA PDFDOI

• Author response for "Photopatternable, Degradable, and Performant Polyimide Network Substrates for E-Waste Mitigation"

  2024-07-08

  peer-review
  PublisherDOI

• Author response for "Photopatternable, Degradable, and Performant Polyimide Network Substrates for E-Waste Mitigation"

  2024-07-02

  peer-review
  PublisherDOI

• Tomographic projection optimization for volumetric additive manufacturing with general band constraint Lp-norm minimization

  Additive manufacturing · 2024-08-01 · 5 citations

  articleOpen accessSenior authorCorresponding

  Tomographic volumetric additive manufacturing is a rapidly growing fabrication technology that enables rapid production of 3D objects through a single build step. In this process, the design of projections directly impacts geometric resolution, material properties, and manufacturing yield of the final printed part. Herein, we identify the hidden equivalent operations of three major existing projection optimization schemes and reformulate them into a general loss function where the optimization behavior can be systematically studied, and unique capabilities of the individual schemes can coalesce. The loss function formulation proposed in this study unified the optimization for binary and greyscale targets and generalized problem relaxation strategies with local tolerancing and weighting. Additionally, this formulation offers control on error sparsity and consistent dose response mapping throughout initialization, optimization, and evaluation. A parameter-sweep analysis in this study guides users in tuning optimization parameters for application-specific goals.

  PublisherDOI

• Generalized projection optimization model for tomographic volumetric additive manufacturing

  2024-03-12 · 2 citations

  articleSenior author

  As a recently developed 3D printing technique, tomographic volumetric additive manufacturing (VAM) enables rapid printing of freeform objects by parallelizing photopolymerization through tomographic exposure. In this tomographic exposure process, patterning resolution and conversion accuracy crucially depend on the design of tomographic projections. In this nascent field, there are only a few optimization algorithms and each proposed to cater certain special cases of the general inverse design problem. Yet, there is no comprehensive and rigorous treatment to simultaneously address the larger class of design problems involving a mix of greyscale targets, non-linear material response, spatially variant tolerance, arbitrary tomographic configuration, and complex propagation media. This paper outlines two contributions to the mathematical and computational foundation for volumetric 3D printing, namely, a general band constraint optimization model and a ray-tracing light propagation model. These advancements are crucial for VAM in creating accurate functionally graded objects in heterogeneous media. Beyond 3D printing, the findings in this work are relevant to synthesis of spatiotemporal irradiation profiles in other contexts, such as those in photografting of biological constructs, 3D neural photostimulation, and intensity-modulated radiation therapy (IMRT).

  PublisherDOI

• Photopatternable, degradable, and performant polyimide network substrates for e-waste mitigation

  RSC Applied Polymers · 2024-01-01 · 6 citations

  articleOpen accessCorresponding

  Photopolymerizable and degradable polyimides from liquid resins were developed, using existing economic chemical feedstocks, as flexible substrates to mitigate the e-waste crisis.

  PublisherOA PDFDOI

• One-pot ternary sequential reactions for photopatterned gradient multimaterials

  Matter · 2023-06-20 · 22 citations

  articleOpen accessSenior authorCorresponding

  Seamless multimaterial construction is a common motif in animal physiology. Such continuous mechanical gradients remain challenging to reproduce in engineered systems, as current resin chemistries typically result in a single fixed set of properties. As an alternative to single-property materials, we introduce a thiol-ene-epoxy-based photothermal reaction scheme that produces multimaterials by altering the polymer microstructure within a single resin. In this system, the photodosage during the first stage of processing dictates the extent of conversion for each subsequent reaction. As a result, our photochemistry can exhibit a diverse range of soft (Young’s modulus, E ∼ 400 kPa; elongation, dL/L0 ∼ 300%) and stiff (E ∼ 1.6 GPa; dL/L0 ∼ 3%) mechanical properties. Furthermore, we pattern photostable and mechanically robust modulus gradients (d[Er, stiff/Er, soft]/dx > 1,000 mm−1) that exceed those found in squid beaks and human knee entheses. We demonstrate the ability to build intricate multimaterial architectures including a soft, wearable braille display.

  PublisherOA PDFDOI

Frequent coauthors

• Robert F. Shepherd

  Cornell University

  28 shared

• Emmanuel P. Giannelis

  Cornell University

  20 shared

• Wenyang Pan

  META Health

  16 shared

• Bobak Mosadegh

  Cornell University

  15 shared

• Kaiyang Wang

  12 shared

• Jérémy Odent

  University of Mons

  11 shared

• Mighten C. Yip

  Georgia Institute of Technology

  10 shared

• Yiğit Mengüç

  Oregon State University

  10 shared

Labs

• The Wallin GroupPI

Education

• Ph.D., Materials Science and Engineering

  Massachusetts Institute of Technology

  1990

• M.S., Materials Science and Engineering

  Massachusetts Institute of Technology

  1986

• B.S., Materials Science and Engineering

  University of California, Berkeley

  1984

Awards & honors

• 2007 Commercialization Fellow, Cornell University
• 2011-15 IGERT Fellow in Magnetic and Nanostructured Material…
• 2009-10 Honors Fellow, Charles Center, College of William an…