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Core-cut ramé-hart Coaxial Spinnerets
Vanilla ice cream is, well, just okay. And
orange sherbet is also okay. But when you put them together to make an
orange creamsicle, you end up with a fantastic frozen dessert that is clearly
superior to its parts. That same magic is what makes coaxial
electrospinning such a powerful tool for producing a vast array of
different types of core-sheath nanofibers. What produces the magic is the
ability to mix and match properties: the core can be strong, conductive,
and biofriendly while the sheath might be elastic, hydrophobic, and
luminescent, for example. The combination of core and sheath materials
and their respective properties is nearly unlimited.
The key to successful coaxial electrospinning is the right spinneret. Over the past decade, we at ramé-hart have built thousands of prebuilt and custom coaxial, triaxial, and quadaxial needles. In fact, no one on the planet makes more custom spinnerets than we do.
One of the key parameters that is important to understand is Dimension C (see DIM C on our Custom Coaxial Needle Worksheet). When DIM C is set to zero, the inner and outer needle tubes are flush at the terminus. While this is often desirable and the default value used on all our prebuilt spinnerets, there are times when a non-zero DIM C value is desired.
Researchers in Israel1 have proven in theory and practice that a positive DIM C value that is less than the diameter of the outer tubing can actually promote entrainment of the core material. For this reason, we often have custom coaxial needle customers who specify a small but positive value for DIM C.
When the core needle is shorter than
the outer needle, DIM C is negative. This condition is also referred to
as core-cut. Researchers in Korea have proven that the core-cut
configuration permits optimized microfluidic flow allowing the sheath
liquid to completely envelope the core solution prior to exiting the
Core-cut coaxial spinnerets, in many environments, will produce more robust hollow fibers than when DIM C is set to zero. In some experiments, C-shaped fibers would result when DIM C was set to zero. But when changed to core-cut, the desired tubular fiber consistently formed properly.
Whether your application calls for a positive, negative, or zero DIM C value, we can make it for you. Another valuable option is to order extra inner needles which we can set to different DIM C values for you - allowing an array of configurations for you to experiment without purchasing multiple redundant outer needle assemblies.
Based on customer demand, we've recently
introduced a new size for our Prebuilt Coaxial Needle. Since the
beginning, the most popular size has been our 22/18 size (22g inner
needle with 18g outer needle). However, with an effort to improve the
outer flow, we've added 22/17 with a larger outer needle.
This makes 22/18 and 22/17 the two
top-selling sizes. To learn more about our Prebuilt and Custom Coaxial
Needles, or to order one, visit this page:
Here are some ways to save on your next spinneret order:
1. Save $105. Order any three or more spinnerets, prebuilt or custom, and get a $105 off your order. Use coupon code SAVE105 during checkout at http://www.ramehart.us/coaxial-needles/. Limit one use per customer. Cannot be combined with other offers. Valid until 1-Dec-2021. Valid for online orders paid with a credit card only.
2. You only need (1) spinneret? We've got
you covered. Use coupon code SAVE35 and get $35 off any prebuilt
coaxial, triaxial, or quadaxial needle. This coupon can also be used on
our Prebuilt Customizable Linear Spinneret Array Kit. Just use SAVE35
during checkout at
https://www.ramehart.us/. Limit one use per customer.
Cannot be combined with other offers. Valid until 1-Dec-2021. Valid for
online orders paid with a credit card only.