PLA(1000)-b-PEG(4000)-b-PLA(1000) is an amphiphilic triblock copolymer composed of poly(lactide) (PLA) end blocks and a poly(ethylene glycol) (PEG) central block. The numbers in parentheses refer to the approximate weight-average molecular weight (Mw) assigned to each segment. The product has a nominal overall molecular weight of approximately 6,000.
The PEG segment is comparatively hydrophilic, whereas the PLA segments are comparatively hydrophobic and contain hydrolytically cleavable ester linkages. This block architecture is used in research examining aqueous self-assembly, micellar and colloidal formulations, polymer degradation, and composition-dependent solution behavior. Aggregate structure, phase behavior, and degradation should be determined for the specific concentration, medium, temperature, and processing conditions used.
Synonyms: PLA-PEG-PLA; poly(lactide)-b-poly(ethylene glycol)-b-poly(lactide).
Key Properties
- Product number: 24503
- Polymer architecture: PLA-b-PEG-b-PLA triblock copolymer
- Nominal PLA end-block Mw: Approximately 1,000 per block
- Nominal PEG midblock Mw: Approximately 4,000
- Nominal overall molecular weight: Approximately 6,000
- Weight-average molecular weight (Mw) by GPC: Lot-specific reported value
- Dispersity (Đ = Mw/Mn): Lot-specific reported value
- Physical state: Solid
- Appearance: White powder or lump
- Package size: 1 g
- Storage: -20°C
Applications
Block-Copolymer Self-Assembly Research
PLA-PEG-PLA triblock copolymers are studied for concentration- and medium-dependent self-assembly arising from the differing solvent affinities of the PEG and PLA segments. Depending on polymer architecture and experimental conditions, PLA-PEG-PLA systems may form micellar aggregates or other organized structures.
Micellar & Colloidal Formulation Research
PLA-PEG-PLA polymers have been investigated in micellar and particulate formulations. Aggregate size, morphology, colloidal behavior, and stability depend on polymer concentration, block architecture, solvent history, preparation method, temperature, and the composition of the surrounding medium.
Encapsulation & Release Studies
PLA-PEG-PLA micellar systems have been studied as polymer matrices for encapsulation and release experiments. Encapsulation efficiency and release behavior are formulation-dependent and should be determined for the polymer grade, incorporated compound, preparation method, and experimental medium being evaluated.
Hydrolytic Degradation Studies
The PLA blocks contain ester linkages that undergo hydrolytic chain scission in aqueous environments. PLA-PEG-PLA materials are used to investigate changes in molar mass, mass loss, morphology, and self-assembled structure during degradation. Hydrolysis depends on variables including pH, temperature, water uptake, polymer architecture, and specimen or aggregate geometry.
Block Architecture & Selection Considerations
- The 1000-4000-1000 designation refers to approximate Mw values of the PLA, PEG, and PLA segments
- The segment values are nominal and should not be interpreted as discrete molecular weights for individual polymer chains
- The nominal overall molecular weight of approximately 6,000 is distinct from the lot-specific Mw reported by GPC
- GPC-derived molecular-weight values depend on the analytical method, calibration, and polymer hydrodynamic behavior
- Dispersity (Đ = Mw/Mn) is reported on a lot-specific basis
- Relative PEG and PLA block lengths influence segment-solvent interactions and therefore solution and self-assembly behavior
- Aggregate morphology and phase behavior depend on concentration, temperature, solvent or aqueous medium, and sample preparation
- A thermoresponsive sol-gel transition or specific gelation temperature should not be assumed from the PLA-PEG-PLA designation alone
Related PLA-PEG-PLA architectures include PLA(1000)-b-PEG(1000)-b-PLA(1000), PLA(2000)-b-PEG(1000)-b-PLA(2000), and PLA(1000)-b-PEG(10,000)-b-PLA(1000). When comparing these materials, PLA and PEG block lengths should be treated as experimental variables rather than assuming equivalent solution, assembly, or degradation behavior.
Application Tips
- Use the lot-specific GPC Mw and Mw/Mn values when molar-mass distribution is relevant to experimental reproducibility
- Keep polymer concentration, medium composition, temperature, and preparation history consistent when comparing self-assembly experiments
- Measure aggregate or particle size directly when morphology is an experimental variable
- For solution phase-behavior studies, characterize the concentration-temperature response of the prepared formulation rather than assuming a predetermined transition
- Control pH, temperature, water content, and sample geometry when comparing hydrolytic degradation experiments
- Keep the polymer dry during storage and handling
Handling & Storage
- Store at -20°C
- Keep the material dry
- Use with good laboratory ventilation
- Wear protective gloves, safety glasses, and suitable protective clothing
- Avoid contact with skin and eyes
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FAQ
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1. What is PLA(1000)-b-PEG(4000)-b-PLA(1000)?
It is a PLA-PEG-PLA triblock copolymer containing two poly(lactide) end blocks and a central poly(ethylene glycol) block. The nominal segment Mw values are approximately 1,000, 4,000, and 1,000, respectively.
2. What do the numbers 1000-4000-1000 mean?
The numbers refer to the approximate weight-average molecular weight assigned to each block: approximately 1,000 for each PLA end block and approximately 4,000 for the PEG midblock.
3. What is the molecular weight of this PLA-PEG-PLA polymer?
The nominal overall molecular weight is approximately 6,000. A lot-specific weight-average molecular weight determined by GPC is also reported for the material.
4. Is the nominal molecular weight the same as the GPC result?
No. The approximately 6,000 value is the nominal molecular weight associated with the block designation. The GPC result is an analytical measurement that depends on the polymer sample, chromatographic method, and calibration used.
5. What does Mw/Mn indicate for this polymer?
Mw/Mn describes the dispersity of the polymer's molar-mass distribution. A lot-specific Mw/Mn value is reported for this grade.
6. Why is PLA-PEG-PLA described as amphiphilic?
The PEG segment has greater affinity for aqueous media than the PLA segments, while PLA is comparatively hydrophobic. The contrast in segment-solvent interactions can promote self-assembly under suitable solution conditions.
7. Does this PLA-PEG-PLA polymer form micelles?
PLA-PEG-PLA triblock copolymers have been studied for micellar self-assembly, but the morphology formed by a particular formulation depends on polymer concentration, medium composition, temperature, preparation method, and block architecture. Aggregate structure should therefore be characterized experimentally.
8. Does this grade form a thermoresponsive hydrogel?
A thermoresponsive sol-gel transition should not be assumed from the block designation alone. Phase behavior in PLA-PEG-PLA systems depends on block architecture, polymer concentration, PLA stereochemistry, solution composition, and temperature.
9. How does PLA-PEG-PLA undergo hydrolytic degradation?
Water-mediated cleavage of ester linkages in the PLA segments progressively reduces PLA chain length. The observed degradation behavior depends on pH, temperature, water uptake, polymer architecture, and the physical form of the sample.
10. How can this grade be compared with other PLA-PEG-PLA triblock polymers?
Related grades differ in the nominal molecular weights of the PEG and PLA blocks. See PLA(1000)-b-PEG(1000)-b-PLA(1000), PLA(2000)-b-PEG(1000)-b-PLA(2000), and PLA(1000)-b-PEG(10,000)-b-PLA(1000).
11. What form and package size are available?
The material is a solid supplied in a 1 g package. The product specification describes its appearance as a white powder or lump.
12. How should PLA(1000)-b-PEG(4000)-b-PLA(1000) be stored?
Store at -20°C and keep the material dry.
13. Is this polymer intended for use in humans?
No. These PLA/PEG biodegradable polymers are offered for research purposes only and are not intended for use in or on humans as a drug or device.
Safety & Documentation
Review the Product Specification for appearance, lot-specific Mw by GPC, Mw/Mn, and storage information. See Technical Data Sheet #365 for PLA/PEG biodegradable-polymer information, the Polymers Product Guide for comparison with related block copolymers, and the Safety Data Sheet for handling and safety information.
