The article explores the physical determinants of viscoelasticity and flow activation energy in biomolecular condensates, using a combination of microrheology and molecular simulations. It demonstrates that the mechanical relaxation times of condensate-spanning networks are influenced by both intermolecular interactions and chain length, while the flow activation energy, representing the energy barrier for network reconfiguration, is independent of chain length and depends on the strength of intermolecular interactions. The study shows that the viscoelastic properties and flow activation energy of peptide-ssDNA condensates are governed by sequence-specific multivalent interactions, with higher activation energy observed in condensates with stronger intermolecular interactions. Chain length variations affect the viscoelasticity of condensates but not the flow activation energy. The results indicate that biomolecular diffusion in the dense phase is inversely correlated with the flow activation energy and is not significantly affected by ssDNA length, suggesting that diffusion is governed by a reaction-limited mechanism. The study also highlights the importance of intermolecular interactions and chain length in determining the viscoelastic behavior and transport properties of biomolecular condensates. Overall, the findings provide insights into the complex material and transport properties of biomolecular condensates and their biological functions.The article explores the physical determinants of viscoelasticity and flow activation energy in biomolecular condensates, using a combination of microrheology and molecular simulations. It demonstrates that the mechanical relaxation times of condensate-spanning networks are influenced by both intermolecular interactions and chain length, while the flow activation energy, representing the energy barrier for network reconfiguration, is independent of chain length and depends on the strength of intermolecular interactions. The study shows that the viscoelastic properties and flow activation energy of peptide-ssDNA condensates are governed by sequence-specific multivalent interactions, with higher activation energy observed in condensates with stronger intermolecular interactions. Chain length variations affect the viscoelasticity of condensates but not the flow activation energy. The results indicate that biomolecular diffusion in the dense phase is inversely correlated with the flow activation energy and is not significantly affected by ssDNA length, suggesting that diffusion is governed by a reaction-limited mechanism. The study also highlights the importance of intermolecular interactions and chain length in determining the viscoelastic behavior and transport properties of biomolecular condensates. Overall, the findings provide insights into the complex material and transport properties of biomolecular condensates and their biological functions.