Phototunable thermoplastic elastomer hydrogel networks
Provided herein is a thermoplastic elastomer hydrogel and methods of making such. The hydrogel comprises a glass formed from poly(styrene)-b-poly(ethylene oxide) in which the coronal chain end has been functionalized with photodimerizable groups (AB-photo) and a liquid medium at a concentration between about 32:1 and about 2:1 liquid medium/AB-photo by weight. The hydrogel has a fatigue resistance to at least 500,000 compression cycles.
1. A method for preparing a block copolymer hydrogel, comprising:
heating a dry blend comprising poly(styrene)-b-poly(ethylene oxide) diblock copolymer in which the coronal chain end has been functionalized with photo-dimerizable anthracene groups (SO-anth) to form an SO-anth melt;
exposing the SO-anth melt to ultraviolet light (UV light) wherein, when exposed to UV light, the components of the SO-anth melt consisting essentially of SO-anth dimerize; and
contacting the UV exposed SO-anth melt with a liquid medium to form a block copolymer hydrogel,
the block copolymer hydrogel having a fatigue resistance to at least 500,000compression cycles.
2. The method of claim 1 , further comprising allowing the SO-anth melt to attain ambient temperature before contacting with liquid medium.
3. The method of claim 1 , wherein the dry blend is heated to 150° C. and then cooled to a temperature of about 70° C. to about 100° C.
4. The method of claim 1 , wherein the SO-anth melt is exposed to UV light from about 1 to about 25 minutes.
5. The method of claim 1 , wherein the SO-anth glass is exposed to UV light having a wavelength of about 320-380 nm.
6. The method of claim 1 , wherein the block copolymer hydrogel has a liquid medium concentration between about 32:1 and 2:1 liquid medium/SO-anth by weight.
7. The method of claim 1 , wherein the block copolymer hydrogel has a liquid medium concentration between about 16:1 and about 4:1 liquid medium/SO-anth by weight.
8. The method of claim 1 , wherein the liquid medium is selected from an aqueous medium, a room-temperature ionic liquid (RTIL), a dialkylcarbonate, an alkylenecarbonate, or combinations thereof.
9. The method of claim 1 , further comprising hydrogenating the polystyrene fully or partially.
10. The method of claim 1 , wherein the compression cycles operate with at least 12% compression at a frequency of about 1 Hz.
11. The method of claim 10 , wherein the compression cycles operate with at least 50% compression at least every eleventh cycle.
12. The method of claim 1 , wherein the fatigue resistance is characterized by a modulus recoverable to at least 80% of its value before the compression cycles were run.
13. The method of claim 1 , wherein the fatigue resistance is characterized by a modulus recoverable to at least 92% of its value before the compression cycles were run.
14. A method for preparing a block copolymer hydrogel, comprising:
heating a dry blend comprising poly(styrene)-b-poly(ethylene oxide) diblock copolymer in which the coronal chain end has been functionalized with photo-dimerizable anthracene groups (SO-anth) to form an SO-anth melt;
allowing the SO-anth melt to attain ambient temperature to form an SO-anth glass;
adding a liquid medium to the SO-anth diblock glass to form a SO-anth diblock solution; and
exposing the SO-anth diblock solution to ultraviolet light (UV light), wherein when exposed to UV light, the components of the SO-anth melt consisting essentially of SO-anth dimerize.
15. The method of claim 14 , further comprising contacting the SO-anth diblock solution with the liquid medium after exposure to UV light.
16. The method of claim 14 , further comprising contacting the SO-anth diblock solution with a second liquid medium after exposure to UV light.
17. The method of claim 14 , further comprising placing the SO-anth diblock solution in a mold.
18. The method of claim 14 , wherein the SO-anth diblock solution is exposed to UV light from about 1 to about 25 minutes.
19. The method of claim 14 , wherein the SO-anth diblock solution is exposed to UV light having a wavelength of about 320-380 nm.
20. The method of claim 14 , wherein the block copolymer hydrogel has a liquid medium concentration between about 32:1 and 2:1 liquid medium/SO-anth by weight.
21. The method of claim 14 , wherein the block copolymer hydrogel has a liquid medium concentration between about 16:1 and about 4:1 liquid medium/SO-anth by weight.
22. The method of claim 14 , wherein the liquid medium is selected from an aqueous medium, a room-temperature ionic liquid (RTIL), a dialkylcarbonate, an alkylenecarbonate, or combinations thereof.
23. The method of claim 14 , further comprising hydrogenating the polystyrene fully or partially.