Adhesion Matters
Adhesion Matters pulls back the curtain on the remarkable world of adhesives—the invisible technologies quietly revolutionizing everything from smartphones and EVs to Hollywood effects and wind turbines. We guide listeners on a deep-entangled journey through innovation, sustainability, and the surprising human stories behind the products that hold our modern life together.
Adhesion Matters isn’t just about chemistry—it’s a storytelling lens on how sticky stuff shapes our world. Every episode reveals that adhesives do more than bind—they enable durability, safety, and innovation across industries. Tune in if you’re curious about the overlooked tech that really holds things together.
Adhesion Matters
Sticking Safely: Medical PSAs, Biocompatibility, and ISO 10993
Why must a medical adhesive stick—and then let go—without harming the skin?
In this episode of Adhesion Matters, we dig into the science—and the sticky business—behind pressure-sensitive adhesives (PSAs) designed for everything from surgical dressings and wearables to wound care patches. We compare key chemistries—silicones, acrylics, and hydrogels—and show how each serves specific medical purposes like temperature resistance, conformability, or moisture management.
We break down the rigorous ISO 10993 standards for biocompatibility, including critical tests for cytotoxicity, sensitization, and irritation. We also spotlight how companies like Dow and Henkel navigate those standards while enabling modern device manufacturing through UV-cure imaging and fast assembly.
Finally, we look ahead to what’s next: from bioresorbable adhesives and smart, medication-releasing patches to PFAS- and solvent-free formulations—showing how the next wave of medical adhesives aims to stick safely while innovating boldly.
Whether you're a materials engineer, regulatory specialist, or just fascinated by where adhesives intersect with healthcare, this episode reveals how smart chemistry keeps us safer—and more comfortable—on the skin.
Welcome to the Deep Dive. Ever stop to think about the incredible, often invisible, technology holding your world together? Adhesives are literally everywhere. I mean, from the screens in our pockets to, well, the medical devices that keep us healthy. Today we're really getting into something fascinating, though maybe overlooked, the highly specialized world of adhesives for medical devices. Our mission really is to understand why these tiny, sticky bits are so critical. How do they stick to delicate skin without causing harm? What kind of incredibly tough standards do they have to meet? We'll also uncover some pretty remarkable innovations from big players like Dow and Henkel that are really pushing the boundaries here.
Elena Bondwell:Yeah, it's so easy to just think glue, right? What we're discussing is completely different. These materials are absolutely fundamental, not just for sticking parts together, but for safety, for comfort, for making sure things work right in really sensitive situations. We're talking directly on skin or even inside the body. So today is really about that intersection of, let's say, advanced chemistry, human biology, and of course, the strict regulations around medical tech.
Lucas Adheron:That's a really important distinction. So when we talk about Medical device adhesives. It's definitely not your average super glue for fixing a broken mug. Our skin, specifically. That seems like a uniquely challenging surface for anything sticky. Why is skin so different? So demanding.
Elena Bondwell:Well, that's the core question, isn't it? Skin is incredibly dynamic. It's not static at all. It's elastic. It stretches. It moves with us constantly. Plus, it's a moist environment, oils, sweat. And it's always renewing itself, shedding cells. Now, compare that to something like metal or hard plastic. Those are static, predictable. Industrial glues often just go for sheer peel strength on those things. But on skin, that kind of aggressive approach would be, well, harmful. A medical adhesive has to bond securely, sure. But it also has to move with the skin. It needs to let the skin breathe. And crucially, it must avoid irritation, allergies, scarring, all of that. So the engineering challenge is huge. It's about adhesion, yes, but adhesion without aggression.
Lucas Adheron:Adhesion without aggression. I like that framing. Okay, so what's the playbook then? For these specialized medical pressure-sensitive adhesives, PSAs, what are the main chemistries involved? And where does each one really excel in this tricky environment?
Elena Bondwell:Okay, so broadly, you're looking at three main families, silicones, acrylics, and hydrogels. And each one brings something different to the party, making them better suited for specific jobs in medicine. Let's maybe start with silicone PSAs. Dow is a big name here. Silicones have some really standout advantages that, frankly, organic adhesives like acrylics or natural rubber just can't match. For one, they perform reliably over a huge temperature range. Think really cold, really hot, they handle it. They're also great at sticking to what engineers call low energy surfaces.
Lucas Adheron:Low energy surfaces? What does that mean in practice, like tricky plastics?
Elena Bondwell:Exactly. Materials that other glues just don't want to grab onto. Silicones are good at that. Plus, they're incredibly conformable. They just mold beautifully to, say, the contours of the skin. And a huge plus, clean removability. They come off without leaving dunk behind or, worse, damaging the skin. They also resist moisture, UV light. They can dampen sound and shock and even act as electrical insulators. Quite versatile.
Lucas Adheron:That is a serious list of benefits. You mentioned sticking to tricky surfaces. What kinds of materials are we talking about inside a medical device?
Elena Bondwell:Oh, all sorts. Think about how complex devices are built. Our sources point to things like glass, various plastics, silicone rubber itself, mylar PET film, which is common. Then you have high performance stuff like Teflon film, PTFE, FEP advanced polyamide films like Kapton often used in flexible electronics, but also more standard things like aluminum foil, stainless steel, even specialized fabrics or silicone coated cloths. So silicones aren't just for skin contact. They're bonding crucial components within the device too across a huge range of materials. And you know, there are subtleties in manufacturing too. Adhesives need curing, hardening. For silicones, you might use peroxide cure systems or platinum cure systems. Different chemistry lets you fine-tune the final properties, flexibility, bond strength, that sort of thing. Another big deal, especially in clean manufacturing, is managing volatile silicones, little bits getting into the air. Products like Dowsell 7x06 VLO adhesive are made specifically to minimize this, to prevent what's called oven dusting.
Lucas Adheron:Oven dusting sounds messy.
Elena Bondwell:It is. Tiny silicone particles can contaminate everything, so low volatility is key for quality control. Okay, now a quick word on the others, acrylics and hydrogels. Acrylic PSAs. They're often known for strong, durable bonds. Good breathability, too. You see them a lot where long wear time is needed, like maybe certain ECG electrodes or surgical drapes. Hydrogels are pretty different. They're usually water-based, highly breathable. Great for wound care because they help maintain a moist healing environment. Extremely gentle on removal, too, though maybe not as sticky initially as the others. And some can even deliver medication right through the gel.
Lucas Adheron:Fascinating. Different tools for different jobs. And speaking of tools, Henkel seems to have a massive toolbox with their Loctitee range for medical devices. What's the scope there?
Elena Bondwell:Oh, Henkel's portfolio is incredibly broad. Their Loctitee medical adhesives include things like instant adhesives, cyanoacrylates, you know, super glue types, but medical grade, plus various UV curing adhesives, acrylics, cyanoacrylates, again, even UV silicones, and then traditional epoxies, hybrids. Basically, they aim to have a solution for almost any bonding task in making a medical device.
Lucas Adheron:Okay, so with that huge range, range, where do these Henkel LLC Gaillet adhesives actually end up? What kind of devices?
Elena Bondwell:Gosh, almost everywhere. Simple disposables like needles, syringes, catheters, tubing, connectors, but also complex stuff. Medical wearables, patches, sensors, critical equipment like dialyzers, blood filters, respiratory gear, surgical tools, prosthetics, hearing aids, endoscopes, big imaging machines. The list is long. And they're designed to bond a real mix of materials. Common plastics like polycarbonate, PVC, ABS, tougher ones like COC, PPP, P, PMA, polyurethanes, plus flexible stuff, silicones again, TPEs, elastomers, and metals like stainless steel. What's really neat about their light cure adhesives, the UV ones, is how fast they cure. Speeds up manufacturing massively. They give strong, reliable bonds, often with flexibility built in for devices that move and bend. And many are fluorescent. Seems minor, but it allows automated cameras using UV light to check every single bond on the production line. Quality control, basically.
Lucas Adheron:Right. Quality control is one thing, but safety, that brings us to a huge point. With all these powerful chemicals sticking things to us or even inside us. How do we know they're safe? Tell us about ISO 10993.
Elena Bondwell:Yes, ISO 10993. This is the absolute bedrock of safety assurance. It's the international standard for the biological evaluation of medical devices. It goes way beyond just does it stick? It looks at how the material interacts with living tissue. Fundamentally, it assesses key things like cytotoxicity. Is it toxic to cells sensitization? Could it cause an allergic reaction and irritation? Will it cause redness, inflammation, that kind of thing? And yes, the sources confirm that essentially all the Henkel Elphi TIT medical device adhesives undergo rigorous testing to meet these ISO 10993 standards. They often mention specific parts like ISO 1093-5 for cytotoxicity, negus 10 for irritation sensitization, maybe mega 4, negative 6, negative 11, depending on the specific use. And it's the same for the dowsley materials distributed by specialists like Bodo Möller Chemie. They ensure everything meets these incredibly strict biocompatibility requirements. This level of biological testing is, well, it's worlds apart from what's needed for, say, office tape. And it's absolutely crucial for getting regulatory approval from bodies like the FDA in the U.S. or the EMA in Europe. Patient safety is the absolute priority.
Lucas Adheron:Okay, so let's make this concrete for you listening. What does all this mean in practice? Think about medical wearables. Those continuous glucose monitors, ECG patches, fancy fitness trackers. Things people wear for days, even weeks. This tech relies completely on these advanced adhesives. It's not just about sticking. It's enabling life-changing technology.
Elena Bondwell:Wearables are such a perfect example. Take a glucose monitor. It needs to stay put for, what, seven days, 14 days, through showers, exercise, sweating, skin moving, all of that. But then when it's time to change it, it has to peel off cleanly. No pain, no irritation, no ripping the skin. And sometimes designers even think about reapplication, maybe repositioning it. Achieving that balanced, secure hold and gentle release is a massive materials science challenge. And it gets even more interesting when when you bring in things like the right to repair movement. You hear about patients trying to, let's say, hack their CGM sensor.
Lucas Adheron:Trying to replace a battery or something to make it last longer.
Elena Bondwell:Exactly. Now, manufacturers might not design for that explicitly, but this kind of user behavior puts new pressures on the adhesive designers. Suddenly, you have to think not just about the initial wear and removal, but maybe potential reuse scenarios, even if unintended. How do you keep it secure but also skin-friendly if someone tries to reattach it? It's a real-world dilemma That's fascinating.
Lucas Adheron:Real world use pushing the design envelope. It really does sound like engineers are constantly performing this high wire act, balancing opposing needs. What are some of those key design tradeoffs they're always wrestling with?
Elena Bondwell:Oh, absolutely. A tightrope walk is a good way to put it. It's all about trade-offs. You need super strong adhesion, right? So the device doesn't fall off. But you also need painless, trauma-free removal. Those two are often in direct conflict. Then there's breathability. You want the skin underneath to stay healthy, not get all clammy like under a cheap bandage. But at the same time, the adhesive probably needs to resist water, sweat, another balancing act. And now there's this growing tension between single-use sterility, historically dominant in healthcare and the push for more sustainable, maybe reusable or repairable devices. How does the adhesive fit into that? And to help manage these tricky balances, companies like Dow also develop supporting materials. Things like primers, Dowsels, 7499 PSA primer is an example. They help prepare difficult surfaces so the adhesive sticks better. Or cross linkers and anchorage additives. These can tweak the adhesive's properties, boost adhesion to tough stuff, but critically without messing up that clean removal. It's all part of the toolkit.
Lucas Adheron:This is clearly such a dynamic field. Looking Moving forward then, what's next? What's on the horizon for medical adhesives? Where's the innovation heading?
Elena Bondwell:There's some really exciting stuff coming down the pike. One major area is bioresorbable adhesives. Imagine adhesives used inside the body, maybe to close a wound or hold tissue, that just naturally dissolve and get absorbed by the body once their job is done. No need for removal. Wow.
Lucas Adheron:Okay.
Elena Bondwell:Then there's the whole area of smart adhesives. We're talking materials that could do more than just stick. Maybe they release medication in a controlled way directly from the patch. Or maybe they incorporate tiny sensors for diagnostics, monitoring things right through the adhesive layer.
Lucas Adheron:Integrated health monitoring in the patch itself.
Elena Bondwell:Potentially, yeah. And another really significant push is towards greener and healthier formulations. Specifically, moving away from PFAS, those forever chemicals, and also reducing or eliminating solvents in the manufacturing process. Dow, for instance, already offers solventless PSAs, like their Dowsell 2102, 2110, 2013 series used maybe for protective films and things like that. It all ties back to minimizing environmental impact and, crucially, any potential long-term health concerns for patients. That's becoming more and more central. You know, when you step back, it's just remarkable. The hidden science, the sheer complexity packed into these seemingly simple, sticky materials, they really are the unsung heroes in so much of modern healthcare, quietly enabling, say, Absolutely.
Lucas Adheron:Unsung Heroes is right. So thinking about the future, as medical technology gets even closer to us, integrating more seamlessly with our bodies, what role do you, listening right now, think these incredibly clever adhesives will play? How will they help make future devices even more personalized, more patient-friendly? Something to think about. Thanks for joining us on this deep dive.
