Surface-functionalised polymeric object and method of its production

1. A surface-functionalised polymeric object ( 10 ), comprising:

a bulk material ( 11 ) comprising a copolymer containing constitution units derived from a first comonomer and constitution units derived from a second comonomer, the first comonomer being L-lactide or D-lactide and forming sequences of oligo(L-lactide) or oligo(D-lactide) in the copolymer, the copolymer having a substantially random, partially blocky structure with a dyad ratio of (lactide-lactide)-dyads to (lactide-second comonomer)-dyads of at least 2.0:1; and

a surface layer ( 12 ) disposed on a surface of the bulk material ( 11 ), the surface layer ( 12 ) comprising a functionalising species and at least one chain of poly(D-lactide) or of poly(L-lactide) covalently bound to the functionalising species, the at least one chain being poly(D-lactide) when oligo(L-lactide) segments are present in the copolymer and being poly(L-lactide) when oligo(D-lactide) segments are resent in the copolymer wherein the surface layer ( 12 ) is attached to the bulk material ( 11 ) via stereocomplexes formed between the poly(D-lactide) chain(s) of the functionalising species and the oligo(L-lactide) sequences contained in the copolymer or via stereocomplexes formed between the poly(L-lactide) chain(s) of the functionalising species and the oligo(D-lactide) sequences contained in the copolymer, respectively.

2. The surface-functionalised polymeric object according to claim 1 , wherein the functionalising species of the surface layer ( 12 ) is a macro-molecule, comprising synthetic polymers and biopolymers; such as proteins, polysaccharides, glycoproteins, proteoglycans, nucleic acids; or a low-molecular weight molecule, comprising synthetic molecules or biomolecules.

3. The surface-functionalised polymeric object according to claim 1 , wherein the functionalising species has 2 or more chains of poly(D-lactide) or of poly(L-lactide) covalently bound to it.

4. The surface-functionalised polymeric object according to claim 1 , wherein the copolymer of the bulk material ( 11 ) has a dyad ratio of (lactide-lactide)-dyads to (lactide-second comonomer)-dyads of at least 2.5:1.

5. The surface-functionalised polymeric object according to claim 1 , wherein a weight content of L-lactide or D-lactide in the copolymer is in the range 55 to 90 wt %, based on the total weight of the copolymer.

6. The surface-functionalised polymeric object according to claim 1 , wherein the copolymer of the bulk material ( 11 ) is selected from poly[(L-lactide)-co-(e-caprolactone)] and poly[(D-lactide)-co-(e-caprolactone)].

7. The surface-functionalised polymeric object according to claim 1 , wherein the copolymer has a weight average molecular weight M w of at least 80 kDa.

8. The surface-functionalised polymeric object according to claim 1 , wherein the bulk material ( 11 ) comprises a blend comprising the copolymer and a second polymer component different from the copolymer and selected from poly(L-lactide), poly(D-lactide), poly[(L-lactide)-co-(e-caprolactone)] and poly[(D-lactide)-co-(e-caprolactone)], wherein the copolymer and the second polymer are selected such that the resulting polymer blend comprises a combination of constitution units derived from L-lactide and constitution units derived from D-lactide.

9. The surface-functionalised polymeric object according to claim 8 , wherein the blend comprises or consists of 80 to 99 wt % of the copolymer and 1 to 20 wt % of the second polymer.

10. The surface-functionalised polymeric object according to claim 8 , wherein the second polymer has a weight average molecular weight M w in the range of 2 to 20 kDa.

11. The surface-functionalised polymeric object according to claim 8 , wherein the polymer blend has an elongation at break in the range of 400 to 1000% at 25° C. and/or has an elastic modulus in the range of 25 to 150 MPa at 25° C.

12. The surface-functionalised polymeric object according to claim 1 , wherein the bulk material ( 11 ) has the form of fibers coated with the surface layer ( 12 ).

13. The surface-functionalised polymeric object according to claim 12 , wherein the fibers have an average fiber diameter in the range of 0.5 to 10 μm.

14. The method of producing a surface-functionalised polymeric object according to claim 1 , comprising:

providing a first solution of the copolymer derived from a first comonomer and a second comonomer, the first comonomer being selected from L-lactide and D-lactide and forming sequences of oligo(L-lactide) or oligo(D-lactide) in the copolymer;

providing a second solution of the functionalising species having at least one chain of poly(D-lactide) or of poly(L-lactide) covalently bound to it; and

subjecting the first and second solution to coaxial electrospinning to produce fibers having a core ( 11 ) of the copolymer and a surface layer ( 12 ) of the functionalising species.