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  • Push and Pull and Flow: The Story of Mechanical and Rheological Analyses

    Push and Pull and Flow: The Story of Mechanical and Rheological Analyses

    What do chocolate bar, toothpaste, rocket seal, ketchup, and touchscreens have in common?

    They all respond when we push, pull, twist, press, or wait on them. Such properties must be fine-tuned for real-world situations. Failure often costs money, user experience, or lives.

    In this newsletter version, I tell the story of how materials resist or give in under force. This is the topic of mechanical and rheological analyses. They are in every aspect of our daily lives. We answer questions like: How strong? How compliant? How squishy? How long will it last before it cracks, flows, or collapses?

    The Classics: Tension, Compression, and Bending

    Let’s start with the basics of mechanical testing.

    When you pull on a material and observe how it responds. This is tensile testing. A stress-strain curve can be plotted by recording the force applied and the deformation it induced. Engineers use this to learn a material’s elasticity, tensile strength, and elongation at break.

    Compression testing, in contrast, measures a material when you squeeze it. This is useful for foams, ceramics, and construction materials. Imagine an earthquake-resistant concrete mix that looked perfect on paper but failed prematurely in a field test. Compression testing under real loading conditions could reveal microvoid formation not visible in the initial lab-grade samples.

    Now let’s say a new carbon-fiber composite we invented passed all tension tests. But when demoed in a curved fuselage panel, it cracked under pressure. This is when flexural strength—how well a material handles bending—is essential. The material can be strong in plane. But flexural testing could reveal delamination under out-of-plane stress.

    The Surfaces: What Indentation Reveals

    Mechanical properties tell stories of materials bulk behaviors. But what if the material surfaces are of great importance in practical settings?

    Nanoindentation is a technique where a microscopic probe presses into the surface of a material to measure hardness and elasticity on the nanoscale. It offers magnifying views into coatings, films, and delicate microstructures. It turns “how hard is this?” into “how does this change across the tiniest regions?”

    Engineers working on flexible electronics use nanoindentation to confirm that the ultra-thin electrodes stayed ductile even after repeated folding. It can also be used to map the local stiffness across dentin and enamel in teeth for better design of dental composites.

    The Wait Game: Watch Materials Evolve

    Instead of pulling or pressing, Dynamic mechanical analysis applies small oscillating forces and tracks how the material reacts at different temperatures or frequencies. It creates well controlled conditions to watch how materials evolve over time. This is the technique behind designing running shoes that feel bouncy in cold Alps and not mushy in the Badwater Ultramarathon. It is also the basis of distinguishing an 80 mph rated tire versus a 120 mph rated one.

    How material evolves over time is pivotal especially when long-term application and life are involved. Creep measures the change in dimensions when a prolonged force is applied. Stress relaxation, on the contrary, records the forces required to keep a certain change in shape for a given period.

    It is possible that a catheter tubing performed well in stress-strain test but deformed after prolonged use inside the body. Creep testing under body conditions reveals slow deformation that wasn’t apparent in short-term tests.

    Stress relaxation, meanwhile, helps engineers understand how a material complies of stress over time. Think of the rubber bands used in orthodontics. Proper relaxation testing ensures their corrective force over days or weeks.

    The Flow: Rheology at Work

    Rheology studies how materials flow under force and how that flow changes over time. It plots viscosity and determines how materials respond under different forces and time intervals. It’s used for designing everything from toothpaste that doesn’t dribble to cement slurry that must remain stable during pumping.

    Recall when You fight with a ketchup bottle. Nothing happens at first. Then suddenly the fries are swimming. This is yield stress—the minimum stress needed to start the flow. If you don’t exceed it, the material behaves like a solid. Go past it, the material flows. Manufacturers tweak yield stress in salad dressings, paints, and face creams to make them behave on demand.

    Some materials show thixotropy—a time-dependent behavior where viscosity decreases over time as you apply stress and recovers itself once left alone. This is not just important for user experience. Think of how paint stirs more easily after a few seconds. And even easier when applied on the wall. Once leveled, it regains its original high viscosity before solidifying for a fine finish. Everyone takes it for granted. Behind the scenes, it is formulation at its best.

    The Outlook

    Mechanical and rheological testing listen to what materials try to say—how they handle forces, for better or worse, under all kinds of conditions. We see these tests as windows into a material’s life story. Every elastic modulus, creep curve, and flow ramp have a real-world tale behind it. At TEMPR Learning, we will learn how to tell their stories that connect fascinating materials characterization techniques to real world impacts.

    In the coming weeks, I will take you deeper into each technique—temperature effect, creep, nanoindentation, yield stress, thixotropy, and more—with storytelling that bridges science and consequence.

    Materials analyses are not boring textbooks. If you can tell the story.

  • Father’s Day

    Dad is the first word in my title. This is the 8th year that I enjoyed Father’s Day. I am always a dad first, then, a scientist.

    Between 2015 and 2017, I failed at many career attempts, from academia to industry. Defeated and demotivated, it was a collective blow to my then ego.

    In 2017, I scrambled to work part-time during the first four months after the birth of my daughter Kristen. I became the night shift feeder, fine tuned the sense of mind-reading of the small baby, and perfected in swaddling.

    Being a father is by choice. Once made, it is a commitment of lifetime. As a parent, we cannot quit like a job. We trial and error, gather thoughts, improve, and correct along the way.

    It turns out that career follows the same mindsets.

    In late 2017, I set aside my ego and started on whatever work and side hustles I can find, watch online causes on Lynda.com (later became LinkedIn Learning), polish my resume, and practice public speaking on any spare time.

    Negativity starts to fade over time. The reality was still barren. But I knew it will get better.

    In 2022, my daughter and I choose June 30th and named it Kristen Daddy Day. A day that holds us together and we celebrate. It is always during summer break and we embark on trips to different states ever since. This life journey will shine through me for all the future times.

    Happy Father’s Day to my dad, all other dads, and myself. Only by being a dad would I realize the delicate role I play in my daughter’s life and how a persistent, dependable, and assertive dad will shape my life and career forever.

  • The Hard and Soft Micromanagement in Research Labs

    Micromanagement in the Lab: A Tale of Two Styles

    I was fortunate enough to experience micromanagement in my earlier days—both the hard and the soft kind. The hard version is obvious; the soft one, covert and well-disguised. All experiences teach us something, especially the bad ones. That’s why I call it fortunate.

    Here are the stories of two micromanagers that explain it better than ChatGPT ever could. I’ve altered their names and some details to focus solely on the substance.

    The Hard Micromanager

    The first one—an acting CTO and R&D Director of a startup, let’s call him Henry—had a daily ritual. He would walk into the lab, stand behind an engineer, and silently observe her operating the glove box. No words. Just silent supervision. Every engineer had their turn in this morning performance.

    Henry began each day with a group meeting, where even the smallest tasks were assigned like chess moves. The day ended with everyone submitting detailed timesheets, broken down into 15-minute intervals. These reports were reviewed, critiqued, and often followed by pointed questions about one’s productivity. The second-floor office became a place of anxiety.

    Nothing happened without Henry’s decision. Whether it was which grant proposal to submit or what brand of pipettes to buy, he made the calls. Suggestions that deviated from his views weren’t just discouraged—they were debated, scrutinized, and often dismissed outright.

    What came out of this hard micromanagement? Everyone did only what was necessary to earn their paycheck. Nothing more. The rest of their energy? Spent job hunting. If you’re a boss paying from your own pocket, this is the worst of both worlds: poor results and wasted money.

    The Soft Micromanager

    Then there was Jon, an academic lab supervisor—kind, helpful, and extremely hands-on. Or so he claimed.

    Jon took on every task, large or small, “so others could focus on the science.” He saw his team members as his own children. He called, texted, and dropped by your lab or office multiple times a day, just in case you needed anything. No response for a day? He’d call the police for a welfare check. I wish I were joking.

    In the lab, Jon ensured every step was documented. He wrote SOPs for everything. If someone tried a different method, he’d “help” by quietly redoing it his way—no complaints, just a quiet correction. He took on far more than he could handle, both mentally and physically, to ensure every task met his standard.

    Want to buy a $200,000 piece of equipment? Jon would schedule a meeting to understand your reasoning. Want to buy a $20 power strip? Same meeting, same protocol. He established multi-level approvals for every purchase. Result? Months-long delays for even the simplest items. But to Jon, this was the responsible way.

    Though less confrontational, soft micromanagement still sends a message: a lack of trust. Or perhaps, more deeply, a lack of trust in oneself. It reflects a belief that others cannot—or should not—be responsible for the finer points of lab operations. Over time, this erodes confidence, stifles independence, and prevents team members from growing into leadership roles.

    Still confused about the impact of micromanagement? Here’s a simple rule: If you can’t offer help without taking over, just walk away.

  • The Stories of Thermal Analyses of Materials

    The Stories of Thermal Analyses of Materials

    Every material has a relationship with heat. Yet, thermal behavior can rarely be something you can guess from a chemical formula, maybe possible for a top-notch theorist. But what is the point of guessing if we can heat the material up before our eyes? It turns out that hands-on is just the beginning.

    Under heat, some materials fall apart at the first sign of rising temperature, others hold steady until something deep inside gives out. It needs to be measured and understood in the context of a story. A story of why a product failed, why a process stalls, or why a brilliant formulation falls short when scaled.

    In this newsletter edition, I will decode the jargon in thermal analysis techniques. Future editions will delve deeper into the essence of each one.

    Let’s begin.

    From Theory to Reality

    In school, we learn thermal theory like it’s gospel. Question and answer are one-on-one. We talk about glass transition as a model zig-zag, melting point as a perfect peak, and decomposition as a single step. The curves are clean. The answers, exact. But in practice? Materials don’t behave like test questions. The data is messy. The peaks are broad and irregular. Sometimes what looks like noise is the actual clue you’ve been missing.

    The first roadblock we face when entering the world of thermal analysis is the jargon. Like many disciplines, jargon seems more formal and professional. But deep down, it is merely a symbol for a technique or a tool that helps us to add context to our story.

    I will start in this introductory newsletter by introducing six of the most common thermal analysis techniques. I am also using an imaginary story for each technique to help you get acquainted.

    DSC: Differential Scanning Calorimetry

    Let’s begin by heating a material and monitoring the energy input and output against temperature. Any physical or chemical change—like glass transition, melting, crystallization, and oxidation—in the material will bring about certain changes in the detected signal. This is DSC.

    A packaging company noticed that their food wrap film turns brittle during shipment in summer. The supplier claimed the polymer’s glass transition was 75 °C, well above shipping temperatures. DSC reveals an energy output peak well below 75 °C. It turns out that some batch of polymer was not fully cured. A simple DSC test avoided further loss and led to updated processing specs.

    TGA: Thermogravimetric Analysis

    From the name, we know it has something to do with heat and gravity. It is right. TGA measures weight changes of a material when we heat it up. Plain and simple. When things burn, decompose, or evaporate, TGA captures all of it. Sounds theoretical enough until the story follows.

    A product line of flame-retardant panels shows inconsistent performance in fire testing. TGA tells that weight loss profiles vary between units, some with weight loss at lower temperature. Tracing back to the raw material source, the vendor admits that a cheaper additive was used instead, which is the cause of early degradation. TGA analysis in this case forges hard requirements in raw material procurement.

    DMA: Dynamic Mechanical Analysis

    Dynamic means changing temperature. Mechanical, well, means mechanical. DMA takes a leap and measures how a material wiggles under a controlled force when heated. This behavior it monitors can tell how much and how well a material can store mechanical energy, or instead, dissipate it. Let me elaborate.

    Clients complain about excessive noise from the interior panels of an EV. Separate mechanical and thermal tests are all compliant. However, when you run a DMA test—which combines thermal and mechanical—it reveals that the polymer lacks sufficient damping at cabin temperatures which turns vibration into noise.

    TMA: Thermomechanical Analysis

    Want to know how and if a material expands or shrinks when heated? This is TMA. Even minute changes in dimensions are well captured, critical for delicate material parts that require durability and stability.

    Let’s run a failure analysis—why something fails—on a delamination issue of a flexible circuit board with TMA layer by layer. The results confirm a mismatch of thermal expansion between the adhesive layer and the substrate. No doubt when temperature increases, the building internal stress is enough to cause layer separation.

    LFA: Laser Flash Analysis

    The name tells nothing about what it does. Let me rephrase. LFA measures how efficient heat moves through a material. We normally refer to as thermal conductivity and thermal diffusivity. LFA is just the most popular way of measuring it.

    All EV batteries need thermal release during operation. We know that. Someone proposes to use a new lightweight composite for the enclosure. Using Laser Flash Analysis, we find that the new material has low thermal diffusivity, too low for rapid heat dissipation from the battery. A follow up formulation idea by adding 10% graphite filler doubled thermal conductivity and the new lightweight battery is in production.

    ARC: Accelerating Rate Calorimetry

    ARC monitors material self-heating at any temperature. An instrument is made so delicate that it gently heats up a material and then wait under the most extreme heat-isolated condition (an adiabatic process) to see if the temperature even increase one hundredth of a degree over time. This sounds like a tedious process. But in the field of ever more popular lithium ion battery, it often means life or death. Here is an example.

    A lithium ion battery supplier wanted to market their new electrolyte with a higher decomposition temperature. A just-in-case ARC test shows a self-heating onset at a temperature even lower than its predecessor. This might be bad news for the R&D team. But it surely saved lives by not having it hit the market.

    They work Hand in Hand

    Each technique tells a different aspect of the story. Much like a movie scene viewed from different angles and lenses. DSC reveals transitions. TGA shows stability. DMA tells you how a material feels under load. TMA monitors thermal distortion. LFA explains heat flow. ARC predicts danger. But used collectively, they do much more than test. They anticipate performance, explain failures, and guide the path to innovation.

    Some of these techniques—DMA and TMA in particular—overlap with mechanical and rheological analysis. Another topic we will be focusing on in the next newsletter edition. When we zoom out and take a God view of all the techniques, it is evident that all of them are interconnected. Our job is to use them to tell a compelling story.

    Looking Ahead with TEMPR Learning

    Instead of advocating for what the school should do, we will take the lead and just put down what we think is important. I am leveraging the TEMPR Learning platform to teach not just the theory for the sake of it, but the story of reasoning, purpose, and results. If you are in R&D, failure analysis, process engineering, or quality control, my mission is to give you both the technical and storytelling tools to succeed. For the new grads and soon-to-be, I am creating a helping bridge to replace your career dilemma.

    Thermal techniques are rarely taught as a whole in school. But they should be, and maybe even blending in the connections beyond the thermal scope. These techniques are seldom used alone in the field. They often work together to guide materials selection, qualify suppliers, solve customer complaints, and keep products safe.

  • A Brief Intro of Each Instrument I manage

    DSC2500:         This thermal instrument measures materials phase transitions (e.g., ice melting) under controlled heating between -90 C and 400 C.

    TG Libra:           This is one of the two TG instruments, part of the thermal instrument family. It measures how materials weight changes upon controlled heating from room temperature until 1100 C.

    Q500 TGA:       Same function as TG Libra but is built by TA Instruments.

    STA:                   This is the most capable thermal instrument in TEMPR Lab. It can measure phase transitions and weight changes at the same time while in-line mass spectrometry and FT-IR enable real-time analysis of gases generated during materials decomposition.

    FlashSmart:      Elemental analysis of C, H, N, S, and O in organic compounds, commonly in quality control in pharmaceuticals.

    ICP-MS:             Elemental analysis of almost all metal elements capable of measuring concentrations down to ppt. Essential tool for drinking water quality control and forensic toxicology.

    easyXAFS:         Using X-ray to identify chemical environments of transition metal elements. Different elements under various chemical conditions absorb X-rays across different energies.

    EDX07000:       Using X-ray induced fluorescence to identify and quantify metal elements within almost any materials in any form, from liquid water to a wedding ring.

    Q800 DMA:      This unit measures delicate solid mechanical behaviors with deformation as small as a few micros unseeable with naked eyes.

    Instron:             This mechanical measurement unit is capable of stretching or compress materials with up to 50,000 N of force. Current configurations are set for plastic materials with maximal force of 500 N.

    3Flex:                This unit can measure surface areas and pore sizes of porous solid materials with pore sizes as small as a few angstroms.

    AccuPyc:           This unit measures volumes of solid materials following the classic pressure-temperature-volume equation.

    APC:                  This unit can measure particle sizes or polymer molecular weights including plastics, drug candidates, proteins, and other biomaterials.

    Rheometer:     This instrument measures all kinds of flow behaviors of liquid materials. It is the essential tool for monitoring the quality of cosmetics, food items, paint, and almost any other liquid products you can think of.

  • Introduction to TEMPR Lab

    Introduction to TEMPR Lab

    The newly established TEMPR Facility in mid-2019 is a world-class shared laboratory for the physical property characterization and elemental analysis of bulk and thin-film biological, soft, and hard materials. The facility houses a suite of state-of-the-art characterization instruments capable of measuring materials’ thermal, elemental, mechanical, physical, and rheological properties.

    Differential scanning calorimeter provides versatile materials phase transition measurements from -90 to 400 °C. In particular, the Discovery series DSC 2500 is equipped with a new Fusion Cell™ for high sensitivity, resolution, reproducibility, and reliability. A linear autosampler allows for worry-free 24/7 operation. Modulated DSC® technology enables efficient separation of complex thermal events. Two thermogravimetric analyzers (Netzsch TG 209 F1 Libra® and TA Instruments TGA Q500) are capable of measuring materials’ mass changes at temperatures from ambient conditions up to 1100 °C with a resolution of 0.1 μg. A simultaneous thermal analyzer NETZSCH STA 449 F3 Jupiter® allows for the measurement of both mass changes and thermal effects up to 1600 °C from a single sample run. An in-line coupled system of a Bruker ALPHA II Fourier transform-infrared (FT-IR) spectroscopy and a QMS 403 D Aëolos® quadrupole mass spectrometer offers comprehensive evolved gas analysis for materials decomposition or desorption.

    A combination of a TA Instruments Discovery series HR-2 hybrid rheometer, a dynamic mechanical analyzer Q800, and an Instron 3365 Universal Testing System can measure mechanical properties of soft materials, liquids, formulations, and composites by introducing force from as little as 0.0001 N up to 500 N.

    A state-of-the-art Thermo Scientific™ iCAP™ RQ Inductively Coupled Plasma Mass Spectrometer offers ultra-trace elemental analysis at sub-ppb to ppt levels and provides elemental screening in minutes. The coupled laser ablation system with a 193 nm pulsed excimer laser allows for solid sample introduction and surface elemental profiling.

    A Waters ACQUITY Advanced Polymer Chromatography (APC) system fractionates and characterizes polymers and nanomaterials with in-series coupled Wyatt μDAWN multi-angle light scattering (MALS) and Optilab UT-rEX refractive index (RI) detectors providing a fast and accurate determination of particle sizes and distributions, absolute molecular weights of polymers, and even 3D geometric features of synthetic or natural macromolecules across a broad range of molecular weights (3000 ~ 2,000,000 g/mol).

  • What the TEMPR Learning

    What the TEMPR Learning

    We used to joke about why we chose materials science grad school over industry jobs. Doubling down, we even pursued postdoc studies, sometimes exceeding the duration of grad school. The joke? We said we cannot find jobs after college. Grad school and postdoc are ways we use to delay the reality that we have to face the real world. Deep down, we knew it was true.

    At the cusp of graduation with a PhD or five years postdoc on the CV, the reality sets in. We exhausted all options and now, we have to find a job. With a decade of academic education and dozens of peer-reviewed publications, we all think we are the perfect candidate for an independent researcher, until we are in the middle of a battle with the odds of 1/500. After the second failed attempt and some recollection, we have to convert the 10-page CV that used to make us proud into a one-page resume. Enters the grand unknown of industry. The textbook knowledge and lab skills become distant overnight. Years of experience post-graduation do not add up. The delayed reality is cruel.

    The Gap Between Academia and Industry

    Many publications noted this gap between academia and industry (see References). Universities often focus on fundamental principles—thermodynamics, crystallography, phase diagrams—at the expense of hands-on training with real equipment. Teachers often provide ideal scenarios instead of realistic conditions. The results? These academic problems always have the right answers—perfect for testing and grading—while industry problems often don’t. To make it worse, interdisciplinary problems are entwined in most practical settings.

    Academic institutions are structured to prioritize research output and theoretical knowledge, not necessarily job readiness. Most faculty have limited industry experience and may not prioritize employability training for the same reason as the story at the beginning of this article—although they are the lucky ones in this context.

    Materials characterization techniques, in particular, are often taught in isolated courses (e.g., thermal or mechanical properties). Students may not understand how data from thermal analysis relates to the mechanical performance of a product. Beyond textbooks, classes rarely teach communication, project planning, or interpreting data for non-technical audiences—key skills in almost all careers.

    For new grads and fresh postdocs facing the industrial world, this leads to the struggle to adapt to hands-on roles involving material testing, quality control, failure analysis, or process optimization, the need to learn everything from scratch once hired, and the risk of underperformance or slow career growth due to low confidence in technical tools. Industry, on the other hand, suffers from increased onboarding time and training costs, risk of avoidable errors or poor decisions based on misinterpreted data, and bottlenecks in R&D and quality workflows.

    Bridging the Gap

    I have long been in the materials science field and experienced the pain of this gap firsthand and in a hard way. Ups and downs in this journey bring many stories to tell, although they have been buried for most of the previous years. At the 6th anniversary of leading TEMPR Lab, I finally decided to wait no more. Here it goes, TERMP Learning.

    TEMPR stands for Thermal, Elemental, Mechanical, Physical, and Rheological materials characterization techniques. TEMPR Learning is a collaborative initiative designed to bridge the gap between academic education and industry application, helping the next generation of materials scientists and engineers turn foundational knowledge into practical skills that matter at work.

    Leveraging the instrumentation in TEMPR Lab, my learning and understanding of relevant techniques, and the technical know-how from experts in various industrial fields, TEMPR Learning will create accessible content grounded in real industry workflows, highligh how thermal, elemental, mechanical, physical, and rheological tools are used in the real world, and equip the next generation materials scientist with industry ready skills, not just technical but also the best way to tell a story.

    What We Try to Solve

    Academic programs focus almost solely on equations and concepts, leaving out more important practical skills that solve real-world problems. A typical mindset expected from a new graduate researcher would be to: find something new -> make it happen -> find where it is useful -> publish it. In contrast, what the real world expects is to: identify a problem -> think of a solution -> leverage the techniques needed -> make the world a better place.

    The contrast is self-evident. Just to list some of the day-to-day skills that we hope that we learned from school: how to select the right technique under time constraints, how to interpret noisy data and to communicate findings to cross-functional teams, and how to link measurements to product decisions. The disconnect induced by a stereotypical academic thinking slows down careers and innovation.

    How We Do It

    We identified the problem. Here is a solution. We change the ways we teach, the subjects we teach, the style we interact with students, and the expectations for the graduates. Sounds appealing but vague. What about the action items and techniques needed?

    For resources, we will employ practical contexts, use-case problem solving, and career-building. We want to build a platform for new grads and early-career scientists and engineers. We’d love to see them choose and apply testing methods with confidence, present compelling stories with eloquence, communicate practical data with persuasion, and build professional reputations with assertiveness.

    For techniques, TEMPR Learning will provide real-world examples, product development workflows, and practical techniques that go beyond textbook theories. We will use case studies to show why TGA and fatigue tests matter in failure analysis and how thermal and mechanical characterizations together reveal the full picture of polymer selection.

    For actions, we will collaborate with industries and technical experts to facilitate interactive workshops, lectures, webinars, peer-to-peer storytelling, and career advice. TEMPR Learning will also focus on forging soft skills, elevating professional presence through effective communication.

    Let’s Amplify

    It is a waste of time fixating on the temporary downward spiral of the political system, even when it inflicts direct harm to education and research. We all feel and empathize. Emotions aside, we witness every day that so many inspiring figures shine the way forward. Bill Gates uses all his wealth to save the world and its people, and solve problems that most countries cannot. We might not have billions to give. But valuables are diverse. Helping is at the center stage. Let’s rise and chip in. Let’s get to work.

    I welcome you to join me on this journey. Let’s learn and grow together. We will make the world a better place, one student at a time.

    Events We are Organizing Next

    TEMPR Learning commits to free learning and mutual personal and professional growth. I am thankful for the many organizations and experts willing to participate and contribute to this initiative. Over the next few months, I will organize a series of workshops in collaboration with TA Instruments. I have been in close connection with TA Instruments for many years, and I am always blown away by how determined they are in teaching the materials society.

    Please stay tuned for the dates and times of these events. More to come.

    Workshop – Thermal Characterization (In summer)

    This workshop will cover characterization techniques in differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), thermal conductivity and diffusivity testing, with cross-examination of dynamic mechanical analysis (DMA), and thermomechanical analysis (TMA). We will bring many application-focused case studies like thermal behavior of phase change materials, thermosets and photo-curable adhesives, thermal stability of polymers and composites, aging and degradation kinetics, and thermal characterization in battery electrolytes.

    Workshop – Rheological/Mechanical Characterization (In summer)

    This workshop draws on the most popular characterization techniques in the industry and will cover both mechanical (e.g., tensile/compression, fatigue, indentation, creep/relaxation) and rheological (viscosity, viscoelasticity, thixotropy, yield stress, and time-temperature superposition) aspects of practical applications. We will also meet at the intersection of mechanical and rheological testing and look at how oscillatory modulus compares to tensile modulus, when rheology can save the project while tensile can’t, and how rheology can track the cure profile of a new material.

    References

    Ramprasad, R., Batra, R., Pilania, G., Mannodi-Kanakkithodi, A., & Kim, C. (2019). Data-driven materials science: Status, challenges, and perspectives. Advanced Science, 6(23), 1900808. https://doi.org/10.1002/advs.201900808

    Chetehouna, V., Béguin, A., Vaudez, S., & Vuillaume, M. (2023). A teaching-learning framework for materials characterization: A case study on a course aimed at equipping undergraduate STEM students with a diversified characterization culture. Journal of Chemical Education, 100(11), 4446–4456. https://doi.org/10.1021/acs.jchemed.3c00974

    Journal of Chemical Education. (2024). Bridging the science practices gap: Characterizing laboratory materials and student experiences in analytical chemistry. Journal of Chemical Education. https://doi.org/10.1021/acs.jchemed.4c00744

  • Get to know about SEC-MALS

    Get to know about SEC-MALS

    TEMPR Learning organized its first event – the SEC-MALS Workshop – on April 3, 2025.

    More to come.

    What the Jargons

    Mixing things can be fun, we know that from watching kids putting play doughs of different colors together. It is a different story, however, if you ask them to separate them. You think, why would I want to do that? It turns out that the separation of matters is as important as mixing them, if not more, once you want to make the world a better place by being a scientist.

    SEC, size exclusion chromatography, a.k.a. gel permeation chromatography (GPC) in the polymer field, is a method for separating matters – as its name suggests – by their sizes. To make it work, a column is packed with porous beads made of materials like crosslinked dextran, agarose, or polystyrene. These beads have pores of various sizes by design. As a sample mixtures flow through the column, matters enter or bypass the pores depending on if they fit in:

    • Larger ones cannot enter any pores and therefore move faster out of the column.
    • Smaller ones visit pores of various sizes. The detour makes a long stay and is, therefore, the last to emerge.
    • Anything in between behaves intermediate in order.

    In its a little over 50 years of history, SEC has evolved into an essential tool in biotech, pharma, nanotech, and polymer industry, shaping everyday life with new materials.

    Detection Methods

    Once the matter is out of the column by size, how to tell it’s there?

    Scientists developed all kinds of ways for this purpose: optical responses, light emission, viscosity, mass spectrometry, or even better, measuring size/mass. By interacting with particles using controlled light (laser), sizes beyond the naked eye can be visualized from light that scatters off particles from different angles. This is light scattering detection at multiple angles, or Multi-angle light scattering (MALS).

    Most methods rely on reference standards to identify the unknowns by comparing them under the same conditions. Light scattering, however, determines molar mass directly from the nature of the material and how it interacts with the media and the light. This is important for materials that do not have standards to compare with. It is not a surprise that all new materials are in this arena.

    With all the tools available to us, optical absorption, refractive index, fluorescence, viscosity, and light scattering, targeted information of a given material is at hand. Moving beyond academic research, industry weighs heavy in SEC-MALS for product development and R&D, in areas of molecular biology, biomedical, pharmaceuticals, and polymer chemsitry.

    Takeaways from the Workshop

    • We get to know this important tool for separating materials and the detection methods available for researchers in different fields – biomedical, pharmaceutical, and polymer industry.
    • The conventional time method disregards material structure by comparing to standards with different conformations. Light scattering, however, takes into account the structure factors unique to each material, which offers a much more accurate picture of the substance.
    • A deep dive into the mechanism behind light scattering in real industrial settings shows how molar mass, size, conformation, and branching of polymers can be determined with SEC-MALS.
    • dn/dc, an important parameter in MALS, reflects how a certain material reacts to its surroundings. It considers chemical structures, dispersion media, environments, and light-matter interaction. Understanding the meaning of dn/dc and ways to measure it is a necessary task for the next generation of scientists transitioning from academia to industry.
    • Software, data interpretation, and data visualization in SEC-MALS help with experimental design for proposing projects, monitoring progress, and evaluating outcomes.
    • Relevant knowledgebase of practical use of SEC-MALS moves us closer to real world applications, away from the learn-for-test mindset.

    About Our Guest Speaker

    We thank Parker Lee from Waters | Wyatt Technology for joining us to discuss SEC-MALS. He joined Wyatt Technology in 2022 as a Field Application Scientist II and teaches customers light-scattering applications to improve and accelerate their research.  He earned his B.S. in Biological Systems Engineering from Virginia Tech and his Ph.D. in Macromolecular Science and Engineering from Case Western University.

    About TEMPR Learning

    TEMPR Learning is an initiative to bring together materials scientists from all sectors to share, learn, and collaborate. We want to bridge the gap between education and real life. What you learn is supposed to give you an edge to be an essential part of the world. Let’s make sure there is one.

    Join Us – Learn and Contribute

    We organize workshops, webinars, lectures, discussions, and more. Free to everyone. Join our TEMPR Learning group for all future events, learn, share, and contribute to free learning.

    References

    Porath, J., & Flodin, P. (1959).”Gel filtration: a method for desalting and group separation by means of dextran gels.”Nature, 183 (4676), 1657–1659.

    W. W. Yau, J. J. Kirkland, D. D. Bly (1979).”Modern Size-Exclusion Liquid Chromatography: Practice of Gel Permeation and Gel Filtration Chromatography.”Wiley-Interscience.

    Andrews, P. (1964).”Estimation of the molecular weights of proteins by Sephadex gel-filtration.”Biochemical Journal, 91 (2), 222–233.

  • 6th Anniversary with TEMPR Lab

    This month marks my sixth anniversary as a core member of the Irvine Materials Research Institute here at UC Irvine. I consider myself lucky to be with UC and even luckier with UCI. I am immensely grateful for the opportunity to broaden my learning in materials research and teach the next generation of scientists.

    Six years ago, I was invited to lead the establishment of TEMPR Lab, a provisional expansion to enable bulk and soft materials research at a whole new level. In a few months, we had installed more than a dozen instruments across multiple materials characterization categories: thermal, elemental, mechanical, and physical. An open house event followed and attracted hundreds of visitors.

    Everything looked bright and shiny. I was ecstatic. The pandemic hit.

    I lost my job instantly, not in the sense of paycheck (UC was generous enough to keep all of us employed even when we did nothing), but on the level of purposefulness.

    For a few months, we had organized awkward virtual games weekly so everyone still felt connected. The lab was, however, at a standstill, with most instruments in sleep mode. We paid a once-a-week visit to the lab, making sure no machine died in our absence.

    Doing nothing took a toll on me. I started gardening and web design, two of my old hobbies. Both ended up fruitful. The former provided a whole year of tomato supply, while the latter, a brand new IMRI website.

    With the momentum, I was able to market the lab remotely and communicate with researchers on and off campus. The potential users grew.

    When the lab finally opened its door to researchers in the fall of 2020, we had already accrued more than 100 users, both academic and industrial.

    Today, more than four years later, TEMPR Lab has grown to house more than two dozen instruments, initiates diverse research collaborations, and helps more than a hundred researchers each year across many academic institutions and industries.

    I am grateful again. More importantly, I feel purposeful.

    Also today, I’d launch TEMPR Learning, a collaborative effort dedicated to free learning of diverse materials characterization techniques. This effort will involve online and in person activities, video, and written know-hows, all of which to be made free to everyone who shares the passion of learning.

    Please join me on this journey and spread the words.

  • Another Review as The End of 2024 Nears

    Within this merit review period, Dr. Xiaofeng Liu has been directing UCI’s Thermal, Elemental, Mechanical, Physical, and Rheological (TEMPR) Facility. He has been overseeing more than 20 materials characterization instruments, teaching bulk materials characterization techniques, and contributing substantially to the overall management of IMRI. Dr. Liu has earned great reviews and respect from users in this position. Dr. Liu also participated actively in research activities and public services within IMRI and across the campus.

    Professional Competence and Activity

    TEMPR Facility was established in July 2019 for the analysis of bulk soft and hard materials across disciplines. The facility joined MRSEC in 2020 and serves an essential role for both on-campus users and researchers from other research institutions and local industry. The facility currently houses a suite of state-of-the-art characterization instruments. The portfolio includes thermal analysis instruments (DSC2500, DSC Q2000, DSC Polyma, TGA Libra, TGA Q500, STA), chemical and elemental analysis instruments (FlashSmart, ICP-MS, easyXAFS, EDX-7000, Aelos QMS, and Bruker FT-IR, Teledyne Laser Ablation System), mechanical and rheological analysis instruments (DMA Q800, DMA 850, HR-2 rheometer, and Instron 3365), physical analysis instruments (3Flex, AccuPyc, and APC-MALS-RI, APC-PDA-RI, and UPLC), summing up to a total of 22 instruments.

    One of Dr. Liu’s primary responsibilities is to oversee the day-to-day operations of many materials characterization instruments listed above, including instrument maintenance, serving the testing needs of academic and industrial users, teaching and training users on these instruments and related techniques, coordinating with service technicians and sales personnel to advance the characterization capability, employing educational activities to researchers across the board, leading the upgrade of the facilities, and promoting the facilities on and off campus.

    1. Dr. Liu has maintained a lab with more than 20 instruments proactively to allow for maximal up time. He has equipped himself with application-level knowledge in teaching and educating all areas that are covered by the TEMPR facility. He could work independently for troubleshooting, component replacement, and repairing other issues. Meanwhile, he has kept a close relationship with all vendors for major instrument repairs and led the effort of upgrading the instruments.
    2. Dr. Liu had provided timely instrument training sessions to users since the lab was established. TEMPR has received growing numbers of training requests each fiscal year: 259 (2021-2022), 283 (2022-2023), and 297 (2023-2024), which were submitted by 119, 144, and 125 unique users, respectively. The total number of unique users between 2021 and 2024 is 309. During these same fiscal-year periods, the total hours of instrument usage in TEMPR Lab are: 6115 hours (2021-2022), 7144 hours (2022-2023), and 8613 hours (2023-2024). The corresponding recharge incomes are: $68k (2021-2022), $75k (2022-2023), and $131k (2023-2024).
    3. Led the acquisition, installation, teaching, and maintenance of UPLC, and APC-PDA-RI under the MRSEC program between 2020 and 2024. Dr. Liu has also:
    4. Led the installation and maintenance of easyXAFS since September 2022.
    5. Led the acquisition and installation of DMA 850 in 2024 under the MRSEC program.
    6. Led the installation and maintenance of EDX-7000 in 2023 from a donation of Shimadzu.
    7. Led the upgrade efforts for Instron 3365 UTS, APC, and HR-2 rheometer in late 2024.
    8. Dr. Liu took UCI compliance training courses and maintained an up-to-date portfolio of chemical and instrumental inventories and safety-compliant documents and lab practices.
    9. Dr. Liu recruited three lab specialists working in assisting users with characterization needs as well as the day-to-day operations of the lab. These lab specialists contributed to user engagement, project services, problem-solving, instrument maintenance, lab maintenance, and marketing.
    10. Dr. Liu made great efforts in attracting external users and providing them with testing services. Staff-run project services have been completed timely to deliver high-quality testing results and technical reports to users on- and off-campus including research institutions and companies.

    Research and Creative Work

    Dr. Liu has been participating in discussing project ideas and developing research collaboration opportunities with research groups in the Schools of Engineering, Physical Sciences, and Medicine as well as startup companies and external institutions. Dr. Liu created promotional material to expand the users reach of TEMPR facility and educate users about TEMPR’s capabilities inside and outside of UCI. TEMPR facility has supported many publications in peer-reviewed journals. A selected list of publications can be seen at the appendix:12 in 2021-2022, 15 in 2022-2023, and 21 in 2023-2024.

    Dr. Liu has maintained an active research profile in line with his primary duty of overseeing the facilities. He collaborated with UCI and external researchers on ten projects. He co-first authored a research paper published in Nanophotonics (DOI: https://doi.org/10.1515/nanoph-2020-0214) during the time in TEMPR.

    1. He was a supporting person for the proposal “Fast, free-breathing, arrhythmias-insensitive, cardiac Quantitative Susceptibility Mapping (QSM) for accurate intramyocardial assessment in iron-targeted intramyocardial hemorrhagic therapy” led by Cedars Sinai Medical Center and UCLA.
    2. He provided five supporting letters for five SBIR proposals led by Ecotune.
    3. He provided a supporting letter for a project by Intelligent Optical Systems.
    4. He was a supporting person for one SBIR proposal by Versatiled.
    5. He served as consultant and co-participant for a grant titled “Ex Vivo Assessment of Muscle Fixation Techniques” led by researchers in the UCI medical school.
    6. He participated in the IMRI open house in 2022 and 2023.
    7. He participated in the MRSEC five-year review by NSF in 2024.
    8. He gave IMRI facility tours to visitors on- and off-campus.

    University and Public Service

    In addition to his job duties, Dr. Liu has been promoting the usage of new tools and software (e.g., Teams) for communication across the team and beyond to improve work and collaboration efficiency.

    Dr. Liu has also been actively involved in event organization for IMRI and CCAM. He has been part of the coordination committee for organizing the annual ISAMS and STEM school. He is also the organizing committee member of the upcoming 16th International Symposium on Ferroic Domains & Micro- to Nano-scopic Structures (ISFD-16). He has designed and maintained all relevant websites and registration workflows for these events.

    Dr. Liu served as the main person in managing, maintaining, and improving the IMRI (http://imri.uci.edu) and MRSEC (http://ccam.uci.edu) websites.

    Dr. Liu served as a contributor for the IMRI and CCAM newsletters.

    Dr. Liu led the kickstart of the Marketing Initiatives to promote IMRI and MRSEC in 2024 which includes the hiring of undergraduate marketing assistants, planning online content marketing, and conceptualizing online webinars and lectures.