Ethyl 2 bromoisobutyrate

γ-CD (Wako, Japan) and PPO-PEO-PPO (comprised of a central block of 90 PEO units and two flank blocks of 5 PO units having M_n = 4580 (Zhejiang Huangma Chemical Industry Group Co., Ltd, China)) were used as received without further purification. 2-Hydroxyethyl methacrylate (HEMA) (TCI, Japan) was passed over a short basic alumina column to remove the inhibitor before polymerization. N,N,N’,N”,N”-penta-methyldiethylenetriamine (PMDETA) and ethyl 2-bromoisobutyrate were purchased from Sigma, USA. Both 2-bromoisobutyryl bromide and 4-dimethylaminopyridine (DMAP) were available from Alfa Aesar, USA. Triethylamine (TEA) (VAS Chemical Reagents Company, China) was refluxed with p-toluenesulfonyl chloride and distilled under vacuum. Copper(I) chloride (Cu(I)Cl) was prepared from CuCl₂, purified by stirring in hydrochloric acid, washed with methanol and finally dried under vacuum prior to use. CH₂Cl₂ was stirred with CaH₂ and distilled under reduced pressure. DMF was supplied by Sinopharm Chemical Reagent Company, China and used without further purification. All other solvents and reagents were of analytical grade.

The methyl methacrylate (MMA; Alfa Aesar, Warsaw, Poland) was dried using molecular sieves (type 4Å, Chempur, Piekary Śląskie, Poland). The [2-(methacryloyloxy)ethyl]-trimethylammonium chloride (TMAMA/Cl; 80% aq. solution, Sigma-Aldrich, Poznań, Poland) was dried to a constant weight under reduced pressure. Methanol and tetrahydrofuran (THF) were purchased from Chempur (Piekary Śląskie, Poland) and dried over the same molecular sieves as MMA. Copper(I) bromide (CuBr; Fluka, 98%, Steinheim, Germany) was purified using a procedure described previously in the literature [42 (link)]. N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA, 98%), ethyl 2-bromoisobutyrate (EBiB, 98%), potassium clavulanate (KCLV), and bis(trifluoromethane)sulfonimide lithium salt (LiTf₂N) were obtained from Sigma Aldrich (Poznań, Polska). Sodium p-aminosalicylate (NaPAS, 98%), sodium piperacillin (NaPIP, 99%), and sodium fusidate (NaFUS, 98.8%) were purchased from Alfa Aesar (Warsaw, Poland) and used without further purification.

N-Isopropylacrylamide (NIPAm, 97%), tert-butyl acrylate (tBA, 98%), β-cyclodextrin
(β-CD), 2-bromoisobutyryl bromide (BiBB, 98%), 1-methyl-2-pyrrolidone
(NMP), dichloromethane (DCM), copper powder (Cu⁰, 99.7%,
45 cm² g^–1), crystal violet (CV, ≥90.0%),
ethyl 2-bromoisobutyrate (EBiB, 98%), copper(I) bromide (CuBr, ≥99.995%),
copper(II) bromide (CuBr₂, ≥99.995%), potassium
fluoride (KF, 99%), trifluoroacetic acid (TFA, ≥98%), spermidine
(99%), basic alumina, and chloroform-d (CDCl₃) were obtained
from Sigma-Aldrich. The (2-trimetylsiloxy)ethyl methacrylate (HEMA-TMS)
was purchased from Scientific Polymer Products. The tris(2-dimethylaminoethyl)amine
(Me₆TREN, ≥99%), gadolinium(III) chloride hexahydrate
(GdCl₃·6H₂O, 99%), anisole (99%), and N,N-dimethylformamide
(DMF, 99%) were purchased from Alfa Aesar. HNO₃ (70%, trace
metal grade) and H₂O₂ (30%, ACS grade) were
purchased from Fisher Scientific. Dialysis bags with desired molecular
weight cutoffs were purchased from Spectrum Lab (Spectra/Por 7). The tBA monomer was purified by passing through basic alumina
to remove inhibitors. Other chemicals were used as received without
further purification.

N-Isopropylacrylamide
(NIPAm,
97%), 2-(dimethyl amino)ethyl methacrylate (DMAEMA, 98%), β-cyclodextrin
(β-CD), 2-bromoisobutyryl bromide (BiBB, 98%), 1-methyl-2-pyrrolidone
(NMP), 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA, 97%),
dichloromethane (DCM), copper powder (Cu⁰, 99.7%, 45 cm² g^–1), Rose Bengal (RB, 95%), Crystal violet
(CV, ≥90.0%), diethylenetriaminepentaacetic acid gadolinium(III)
dihydrogen salt (Gd-DTPA, 97%), ethyl 2-bromoisobutyrate (EBiB, 98%),
copper(I) bromide (CuBr, ≥99.95%), copper(II) bromide (CuBr₂, ≥99.995%), potassium fluoride (KF, 99%), basic alumina,
and chloroform-d (CDCl₃) were obtained from Sigma-Aldrich.
(2-Trimethylsiloxy)ethyl methacrylate (HEMA-TMS) was purchased from
Scientific Polymer Products. Tris(2-dimethylaminoethyl) amine (Me₆TREN, ≥99%), gadolinium(III) chloride hexahydrate (GdCl₃·6H₂O, 99%), anisole (99%), and N,N-dimethylformamide (DMF, 99%) were purchased from
Alfa Aesar. HNO₃ (70%, trace metal grade), Silwet L-77,
and H₂O₂ (30%, ACS grade) were purchased from
Fisher Scientific. Dialysis bags with desired molecular weight cutoffs
were purchased from Spectrum lab (Spectra/Por 7). The DMAEMA monomer
was purified by passing it through basic alumina to remove the inhibitor.
Other chemicals were used as-received without further purification.

Paper pulp used in this study were kindly provided by Chung–Hua Paper Inc., Taiwan (LBKP grade). Cupric bromide (CuBr₂, 99%) 4,4–dimethylaminopyridine (DMAP, 99%), 2–bromoisobutyryl bromide (BiB, 97%), 2,2,6,6–tetramethylpiperidin–1–yl)oxyl (TEMPO, 98%), 2,2′–azobis(2–methylpropionitrile) (AIBN, 98%), ethyl 2–bromoisobutyrate (EBiB, 99%), N,N,N’,N´´,N´´–pentamethyldiethylenetriamine (PMDETA, 99%), methyl methacrylate (MMA, 99%), and triethylamine (TEA, 99.5%) were purchased from Sigma–Aldrich (Darmstadt, Germany). Sodium hydroxide (NaOH, 96%), hydrochloric acid solution (HCl_(aq), 35%), sodium bromide (NaBr, 99%), and sodium hypochlorite aqueous (NaClO_(aq), 12%) were purchased from Showa Corporation (Saitama, Japan). Commercial PMMA with average molecular weight (M_n) of 600,000 g/mol was purchased from Polyscience (Niles, IL, USA). All solvents were used without any further purification.