Do you have any knowledge about the elasticity of silicone? Then, do you know what applications it has? You can describe its characteristics, but you can’t easily associate them with practical applications. This article will tell you about the various applications and help you understand the elasticity of silicone elastomers, and make better judgments and choices.
Consumer Electronics and Wearable Devices
Smartphones, Tablets, and Portable Electronics
On devices like smartphones and tablets, silicone elastomer is often used in places that you can’t see. You may not be familiar with it, but these areas, such as the interfaces and gaps that you frequently use, are often utilized. These areas are almost involved in the stability design of the entire device. The materials need to be soft, able to be repeatedly compressed, and not prone to aging. Common locations are concentrated on the sealing rings of USB/Type-C interfaces, the sealing of SIM card slots, microphones, and the waterproof membranes around speaker openings. These areas are small in space, have tight assembly tolerances, and require repeated insertion and removal. Silicone elastomer deforms stably under pressure and does not collapse even after long-term use.
Inside the structure of a mobile phone, silicone elastomer is often used as a material for buffering and shock absorption, such as the buffer pad for the camera module, the shock-absorbing pad for the battery or the motherboard, and the elastic gasket between the screen and the frame. It is not for the silicone elastomer to bear the weight, but to utilize its flexibility and stretch ability to absorb the instantaneous stress caused by drops or compressions. This way, the direct transmission of drop or assembly stress to the precision components can be prevented.
Apart from the two aforementioned uses that aim to extend the applicability of the equipment, other purposes aim to enhance the user experience. You can often see silicone elastomer on the buttons and some of the shell sealing parts. It is used to improve the touch feel of the device, resist sweat, grease, and not attract dust.
Wearable Devices and Smart Accessories
This type of equipment is used in close contact with human skin for a long time. The silicone elastomer has excellent biocompatibility and the advantage of not releasing irritating gases or harmful substances. It has little irritation to human skin and is unlikely to cause allergies. Moreover, it is resistant to sweat and sebum. It is commonly used in watch bands, ear caps, and earplugs of headphones, as well as the cushioning pads in the fitting areas.
The electronic devices used daily are exposed to various environments, such as human sweat, rainwater in the environment, and temperature variations. The temperature resistance and chemical stability characteristics of silicone elastomer can be applied to the sealing around sensors, protection of charging contacts, and elastic sealing at the joint parts of the shell.
Power Supply and Charging Equipment
In power adapters and chargers, their main functions are insulation, buffering, and sealing. There are many high-voltage circuits and small electronic components in the adapter. Silicone elastomer can be applied to cover the surface of the circuit board or components, to prevent short circuits and isolate the user from the high-voltage parts.
Power Adapters and Chargers
Power adapters and chargers can be found almost everywhere. The safety of these devices is very important. Silicone elastomer serves as an insulating protective layer on the internal circuit board, covering high-voltage components or chips to prevent short circuits or leakage. At the interface of the adapter casing, it can prevent dust and water from entering. Portable chargers often use silicone elastomer for sealing to prevent water leakage and electricity leakage.
The silicone elastomer has excellent fatigue resistance, as well as good wear and stretch resistance. It is commonly used in cable interface kits or buffer pads to reduce wire wear and interface loosening. When the power of the power supply equipment is high, the temperature of the equipment is prone to rise. The silicone elastomer has good high-temperature resistance. It will not melt and can maintain the normal operation of the equipment.
Power Modules and Energy Storage Components
In power modules, silicone elastomers are mostly used in areas that are most subjected to vibration and mechanical shock. Silicone pads are placed between the modules. They can absorb external vibrations and prevent the force from directly reaching the screws, busbars, or internal connectors. Without this layer of pad, these components may loosen or develop micro-cracks over time.
In lithium battery modules, silicone is used as a sealing ring. When the battery is charged, it expands; when it is discharged or cooled, it contracts. If the sealing does not change correspondingly, small gaps will occur, allowing moisture to seep in. The terminals and detection points are usually the first places to be corroded.
Silicone elastomer is used to fill the uneven gaps between power devices and heat sinks. Without it, air would be trapped. Over time, the device might overheat or age unevenly.
In large-scale energy storage systems, sealing also has to cope with minor movements of the structure. Rigid seals may seem fine at first, but when the temperature rises, the seals would be pushed out, or they may transfer the pressure to the outer shell, causing cracks around the sealing groove.
How much hardness is determined by the type of module. For industrial high-power modules, choose a silicone elastomer that is on the hard side to keep shape and insulation distances when subjected to force. If it’s too soft, it changes shape when pressure is applied, the creepage distance becomes shorter, and the electrical risk rises. Consumer electronics prefer softer silicone, which can cushion drops and assembly errors. Otherwise, solder joints and connections are easily injured by extra stress.
PCB Protection and Electronic Encapsulation
In electronic devices, PCBs are vulnerable to humidity, dirt, temperature variations, and vibrations. All these factors gradually accumulate risks. The silicone elastomer works as a buffer zone for the circuit board.
Conformal Coating for PCB Protection
On many consumer power boards, the silicone elastomer is used in the form of a three-proof coating rather than being fully encapsulated. The circuit design stays the same; only a thin protective layer is added on the surface. The reason for this is quite practical – when the whole board is sealed, it is very difficult to conduct post-assembly inspections and maintenance.
On the power board and control board, the coating will cover the solder joints, interfaces, and wiring. The areas with dense solder joints and interface positions are usually the key areas, as water vapor and oil mist are most likely to accumulate in these places. If these positions are exposed, after long-term operation, leakage is likely to occur first from here.
The high-voltage area places much more dependence on this coating. Without a protective layer, in damp or dusty environments, the surface of the board will gradually create a route for electrical leakage. The problem is not typically a single breakdown, but rather frequent abnormal alarms or unstable insulation.
During the temperature cycling process, the PCB itself will undergo slight bending, and the solder joints will also move accordingly. If a rigid coating is used, it is very likely to crack at the solder joint location. The silicone elastomer can deform along with the board and will not concentrate the stress in a specific location. If there isn’t the elasticity, fatigue of the solder joints is likely to occur first, and the problem will repeatedly occur in the same area.
Potting and Localized Encapsulation Solutions
When the operating environment becomes more stringent, surface coatings alone are simply not enough. In power modules and automotive electronics, silicone elastomers are used for potting or partial encapsulation. It prevents the ingress of moisture and dust, and is also effective in minimizing the direct transfer of vibration to the delicate unit. Without these encapsulations, mechanical shocks can directly affect chips and solder joints, leading to early damage.
In most actual situation, the board is usually not sealed wholly. If everything is sealed, there is no extra room for thermal expansion and contraction to release pressure. Over time, the material can’t absorb this pressure and instead transfers it to components and solder joints, which can eventually crack or fail. Areas under heavy stress (power supply devices, critical chips) and fixing points are the areas to concentrate on, and other areas are sometimes purposely left unsealed. The choice of hardness is usually determined by structural requirements and impact resistance.
Communication Equipment and 5G Hardware
Base Stations and Outdoor Communication Units
Equipment like outdoor base stations and communication cabinets is exposed to the outdoors and often experiences challenges from the elements and temperature differences. To protect them from the elements, silicone elastomers are used for sealing and protection. It is used in the cabinet door frames, seams, around cable outlets, and connectors.
Silicone can withstand long-term compression, keep its shape stable, and stop water vapor and dust from entering. The silicone elastomer is not prone to deformation, even when exposed to alternating heat and cold. When the board temperature fluctuates dramatically, the silicone remains pliable and does not crack or loosen. It also effectively absorbs vibrations caused by wind or fan operation, reducing damage to solder joints and interfaces.
Antennas, RF Components, and Signal Modules
Antenna and RF modules are very demanding in terms of location. Because if they are even slightly offset, the signal is affected. Silicone elastomers act mainly as fixation and cushioning on these components, ensuring that they work stably.
It is often used in locations between the radome and the main body, the internal gasket of the module, the coaxial connector, and the feeder outlet. It is used to avoid movement in these locations due to vibration or temperature differences. It is not easy to be powdered or peeled off in high frequency environment, small vibrations and stress will be absorbed by the silicone, and will not be directly transmitted to the sensitive parts. So it is very suitable for maintaining the stable operation ofthe RF module.
Automotive Electronics and In-Vehicle Systems
Devices like in-vehicle sensors (radar, camera and ADAS sensors), battery modules and motor controllers are often exposed to the external environment and are susceptible to dust and moisture. Silicone elastomers are used in these sensors as seals or encapsulants to keep out dust and moisture. It is flexible and will expand and contract during temperature changes to protect the proper functioning of the part and can also fit the shape of the part. It can stretch to prevent yet fit well without affecting the signal transmission. It also absorbs stress during vibration, minimizing the damage it can cause to the component.
Industrial Automation and Control Equipment
Control Cabinet and Electronic Module
In industrial control cabinets, circuit boards are usually arranged very densely. External dust, oil mist, or moisture is likely to affect circuit operation. Silicone elastomers isolate these external elements by means of coatings or localized encapsulation. Localized gasketing or encapsulation also absorbs mechanical vibrations and reduces fatigue in solder joints and components, therefore extending service life.
Sensors and Actuating Components
Silicone elastomers are used to seal components such as industrial robots, sensors and servo motors against dust, water and vibration.
Power Supply and Power Module
Silicone elastomer gaskets and encapsulation materials in industrial power modules are also used to waterproof, dustproof, and reduce the impact of vibration. It also maintains a stable form at high temperatures. So, what hardness and thickness of silicone elastomers to choose? It depends on the part of the body being used. Hard materials are used for bracing or structural support, while soft materials are used for vibration absorption or sealing. The right design increases the reliability and lifetime of the power module without the need for additional mechanical parts.
Medical Electronic Devices
Wearable Medical Devices
Devices such as heart rate monitors, blood glucose meters, and wearable blood pressure monitors use silicone in the straps, cushion pads, and areas where the sensors are in contact with the skin. It feels soft, is gentle on the skin, causes almost no allergic reactions, and won’t deform even when sweating or being frequently wiped. This way, when wearing the instrument all day, the strap won’t cause red marks on the wrist, nor will it make the wrist itchy. The sensors remain firmly attached to the skin, ensuring accurate measurement results.
Medical Devices
Surgical instruments, catheters, and monitoring equipment are prone to bumps. Over time, this may cause the equipment to malfunction prematurely or result in inaccurate readings. Silicone is used as small seals, O-rings, or protective coatings. It is able to stop water and dust from entering, and also absorb vibrations. If a portable monitor is bumped during transportation, the silicone sealant can take the blow and protect its internal circuits and sensors.
Energy Supply and Cooling
Medical equipment has very high requirements for power stability and heat dissipation. Silicone elastomer is usually placed between the power board and the heat sink to help evenly distribute the heat. Its thickness and hardness can be adjusted according to the equipment. For example, on a portable infusion pump, a 2-3 millimeter silicone pad can reduce minor vibrations without affecting the heat dissipation. Without it, these devices are prone to local overheating, accelerated wear of solder joints, and prolonged accumulation of small vibrations. All of these could result in more severe issues.
FAQ
How do Silicone Elastomers Perform in Long-term or Continuous-use Applications?
Pretty good. Even if you wear it every day, or the device is constantly being squeezed, stretched, or exposed to hot and cold cycles, it won’t become hard, crack, or come loose. If you have a blood sugar monitor and wear it for two consecutive weeks, the strap still shows no problems, the sensor is firmly attached, and the data is still accurate.
Can Silicone Elastomers Be Customized for Distinct Application Demands?
Sure. You can be firm or soft as you like, and the thickness would be adjusted. The industrial power board might require firmer sealing pads to support the structure, while the bracelet strap needs to be pliable and skin-friendly for comfort. By adjusting the filling ratio, you can also control the heat resistance, cushioning, and chemical corrosion resistance.
What Makes Silicone Elastomers Suitable for High-temperature Applications?
Its main molecular framework is a silicon-oxygen chain, which is structurally stable. It can withstand temperatures ranging from -60℃ to 300℃. Unlike ordinary rubber, which becomes soft or deforms when heated, silicone rubber remains stable.
What are The Most Common Applications of Silicone Elastomers?
There are many types: wristband, shock-absorbing pads, PCB coatings, local encapsulation, thermal interface pads, and even the raised tactile layers beneath car dashboards or factory machine buttons are all being used. As long as there is a need for shock absorption, waterproofing, dustproofing or heat dissipation, you can almost always find it.
How Do Silicone Elastomers Perform as Electrical Insulators?
Very good. It can withstand high voltages, moisture and dust. In the power module, PCB coating and sensors, it can avoid short circuits and leakage, making sure the equipment runs safely.
Can Silicone Elastomers Absorb Shocks or Vibrations?
Sure, and the effect is quite good. It is soft and has good flexibility. It can disperse vibrations and impacts. The small pads under the PCB, the sealing pads for the power module, or the shells of the detectors can all protect the solder joints and precision components from being damaged. Without it, even small vibrations accumulated in the long time would potentially cause malfunctions.
Final Thought
Silicone elastomers can be found in almost all electronic devices, ranging from mobile phones, smart wristbands, power modules, PCB protection, to industrial equipment, automotive electronics, and even medical instruments. It can seal gaps, prevent water and dust from entering, absorb minor impacts and vibrations, be resistant to high temperatures, and help disperse heat. It is essentially a small shield for the equipment, protecting components from being damaged by thermal expansion and contraction or minor impacts.
The custom solutions for Legensilicone are highly flexible. The material, hardness, thickness, and shape can be customized to fit your needs. If you require gaskets, local encapsulation, PCB coatings, thermal interface pads, wristband straps, buttons, and tactile layers, we can handle them all. Those who have used them will find that these items are durable, comfortable, and less exposed to difficulties. They are easy to use and maintain. If you need any help, contact us at any time.
