title: Microfluidic synthesis of tunable poly-(N-isopropylacrylamide) microparticles via PEG adjustment.
abstract: We present a microfluidic droplet method to synthesize a series of tunable poly(N-isopropylacrylamide) (PNIPAM) microparticles by the addition of polyethylene glycols (PEGs). The PEGs are used as porogens and could be removed simply by washing step. By varying molecular weights and concentrations of the PEGs, morphologies and temperature-sensitive properties of the formed PNIPAM microparticles are flexibly tuned. It is found that PEG of lower molecular weight induces smaller micropore sizes, and results in faster response rate. The volume changes prior to and after shrinkage can also be regulated by the addition of PEGs due to tuned homogeneities of micropores. The microparticles tuned by PEG1000 with ratio of added PEGs to NIPAM of 2:1 respond the fastest (120 s), whereas with ratio of added PEGs to NIPAM of 1:1 display largest volume change (1/γ=12.12). This simplicity and controllability of tunable microparticles synthesis are appealing for various applications ranging from chemical delivery, drug release control, to optical applications.
authors.affiliation: Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, P R China.
authors.forename: Shuqiang
authors.initials: S
authors.lastname: Huang
authors.forename: Bingcheng
authors.initials: B
authors.lastname: Lin
authors.forename: Jianhua
authors.initials: J
authors.lastname: Qin
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D000180:Acrylic Resins; D044085:Microfluidics / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D016062:Porosity
chemical_list: D000178:Acrylamides; D000180:Acrylic Resins; D011108:Polymers; C052970:poly-N-isopropylacrylamide; D011092:Polyethylene Glycols